P

package dealer A person or organization assuming responsibility under a single contract for the design and construction of a project to meet the specific requirements of another.

packaged fan equipment See air-handling unit.

packaged house A prefabricated house composed of building components cut to size at the factory and/or manufactured components that are commercially available.

package stability The ability of a liquid, such as paint or varnish, to retain its original quality after prolonged storage.

package trim Factory-made door and window trim, ready for installation; delivered to the job-site in packages.

packed chord A composite chord, 1 which consists of several longitudinal structural members that are bolted together.

packer 1. A device, usually expandable, which is inserted into a hole to be grouted; prevents return of the grout around the injection pipe. 2. Same as compactor, 2.

packing 1. The stuffing or a thin ring of elastic material around a shaft or valve stem, or around a joint, to prevent fluid leakage. 2. Small stones embedded in mortar; used to fill the cracks between the larger stones.

packing piece, stool A block which is used to raise one or more members above others.

pack set The condition induced in stored cement (whether in stationary containers or during bulk shipment) of reduced ability to flow freely; usually caused by interlocking of particles, by mechanical compaction, or by electrostatic attraction between particles.

pad See padstone.

padauk A hard, heavy wood, red with black stripes, from India; used in cabinetmaking and veneer.

paddle A flat plastering tool used to clean out or to finish an angle or corner.

paddle mixer A mixer for concrete or mortar having power-operated mixing blades which revolve about an axis.

paddock A small field near a house or barn in which animals, usually horses, are enclosed.

pad foundation An isolated, concrete slab on-grade, 1 that serves as a foundation.

pad-mounted transformer A transformer designed to be mounted directly on a pad foundation with high- and low-tension cables coming directly into the terminal compartments which are part of the transformer housing.

pad saw A small compass saw.

padstone, pad A strong block bedded on a wall to distribute a concentrated load; a template, 2.

pad support In an acoustical ceiling assembly with a perforated metal pan, a device (such as a wire grid) for holding the sound-absorptive element out of contact with the perforated pan.

page A short thin wedge.

PageFormat A page organization for specifications as set forth by the Construction Specifications Institute.

pagoda A multistoried shrine-like tower, originally a Buddhist monument crowned by a stupa. Stories may be open pavilions of wood with balconies and pent roofs (prevalent in Japan) or built-in masonry, of diminishing size with corbeled cornices.

paillasse Same as palliase.

paillette In decorative work, a bit of metal or colored foil used to obtain a jeweled effect.

paillon Bright metal foil, used to show through a thickness of enamel or paint to alter its color and give it brilliance.

pai-lou, pai-loo A monumental Chinese arch or gateway with one, three, or five openings; erected at the entrance to a palace, tomb, or processional way. Usually built of stone in imitation of wood construction.

paint A liquid solution of pigment in a suitable vehicle of oil, organic solvent, or water; liquid when applied but dries to form an adherent, protective, and decorative coating. Often categorized according to the solvent used for thinning, for example, water-thinned paint or solvent-thinned paint. Also see acrylic paint, cement-water paint, epoxy paint, latex paint, synthetic rubber-base paint, vinyl paint, water-based paint.

paint base The vehicle into which pigment is mixed to form a paint; commonly alkyd, latex, acrylic.

paint bridge A platform or gallery, of fixed or adjustable height, beside or above the stage of a theater or in a paint loft; esp. used to paint scenery.

paint brush A tool for applying paint, consisting of a flexible brush composed of long filamentary material bound to a handle.

paint drier See drier.

painted glass A decorative glass that is colored by the application of an enamel paint onto a glass surface that is then heated in a kiln at a high temperature; see stained glass.

Painted Lady style A mode of 19th-century Victorian architecture in which the exteriors of houses are characterized by bright, contrasting colors; San Francisco has an abundance of such houses.

painter’s putty See putty.

paint frame A movable frame, which can be raised or lowered, used to hold stretched canvas (and/or “flats”) on which stage scenery is being painted.

paint kettle, paint pot An open can with a bail (wire handle) for carrying or hanging on ladders while painting.

paint loft In a theater, a narrow vertical loft containing paint frames and/or paint bridges.

paint oil See drying oil.

paint pad A tool for applying paint, consisting of short filament material or an open-cell resilient material which is connected to a handle; designed to apply paint by a wiping action.

paint remover A liquid which is applied to a dry paint or varnish to cause it to soften or lose adhesion so that it may be removed easily.

paint roller A cylindrical tube which is coated on the outside with nonwoven fibers such as nylon, mohair, and lamb’s wool and mounted on a roller with a handle; used for application of paint or varnish.

paint spray booth See spray booth.

paint sprayer See spray gun.

paint system The surface coating on a painted object; built up from some combination of the following coats: sealer or primer, stain, filler, undercoat, topcoat, varnish coat.

paint thinner See thinner.

paired brackets Two closely spaced brackets that form a pair; also called coupled brackets.

paired gables A façade having two gables that form a pair; for example, sometimes found in the façades of Gothic Revival structures of wood construction.

palaestra A Greek or Roman building for athletic training, smaller than a gymnasium, consisting of a large square court with colonnades, rooms for massage, baths, etc.

palazzo In Italian cities, a large, separate dwelling, often lavish; one of the major categories into which the Italianate style is often divided.

Palazzo style See Italian Renaissance Revival in which palazzi were widely imitated.

paldao See dao.

pale 1. A flat strip (slat) or round stake, usually of wood; set in series to form a fence. 2. An area enclosed by such stakes.

pale-bodied oil See boiled oil.

pale brick Same as salmon brick.

palestra Same as palaestra.

paling See pale.

palisade A series of stout poles, pointed on top and driven into the earth, used as a fence or fortification. Also see stockade.

palisado house A primitive house or building, usually built in frontier areas; walls were once constructed by setting two parallel rows of logs upright into the ground, and then filling the space between the rows with mud and twigs, or clay mixed with stones.

palisander See Brazilian rosewood.

palladiana See berliner.

Palladian dormer A dormer having a window, divided in three parts, that is suggestive of a small Palladian window.

Palladian door A door topped with a rounded arch; flanked by vertical rectangular areas of fixed glass on each side that are narrower and usually not as high as the door; suggestive of the appearance of a Palladian window.

Palladianism A term descriptive of a style of building that follows the strict use of Roman forms, as set forth in the publications of the Italian Renaissance architect Andrea Palladio (1508–1580), particularly under the influence of Lord Burlington in the 18th century.

Palladian motif, Serlian motif, Venetian motif A door or window opening in three parts, divided by posts, with a lintel flat over each side but arched over the center.

Palladian Revival See Anglo-Palladianism.

Palladian window A large window divided in three parts: a central sash that is arched at the top and two sashes on each side of it that are smaller than the central sash; the smaller sashes are rectangular, topped with flat lintels. Compare with three-part window. (See illustration p. 698.)

pallet 1. A flat piece of wood laid in joints of brickwork to allow fastening of woodwork to wall. 2. A portable platform used to facilitate handling by a forklift.

pallet brick, pallet slip A brick esp. made with a groove along one edge to receive a pallet, 1.

palliase In masonry, a supporting bed.

palma cottage A primitive one-room dwelling having a steeply-pitched gable roof which is thatched with overlapping palmetto fronds attached to a wood framework; provides a relatively watertight roof and walls. Temporary dwellings like these were constructed by early Spanish colonists in Florida.

palmate 1. A column capital resembling the leaves of a palm tree. 2. A palmette.

palm capital A type of Egyptian capital resembling the spreading crown of a palm tree.

palmette An ornament derived from a palm leaf.

palmiform Having the form of a palm leaf or the crown of a palm tree.

pamment A thin square paving brick.

pampre An ornament consisting of vine leaves and grapes used to fill cavettos and other continuous hollows in a group of moldings.

pan 1. A wall plate. 2. A part of an exterior wall; esp. in half-timbered construction, the wall spaces between the timbers. 3. A major vertical division in a wall. 4. A structural panel. 5. A form, frequently of molded fiberglass, used in pouring concrete floors or roofs. 6. The re-cessed bed for the leaf of a hinge.

panache The curved surface of a pendentive.

pan-and-roll roofing tile Single-lap roofing tile of two types used in combination: a flat, tapered undertile having flanges, and a half-rounded tapered overtile.

pan breeze, breeze Small bits of coke and furnace clinker from the pan beneath a coke oven; suitable for use as aggregate in lightweight concrete block.

pancarpi Garlands or festoons of flowers, fruits, etc.

pan construction A concrete floor or roof construction in which a prefabricated form (pan, 5) is used repeatedly, giving the underside of the construction a waffle-like appearance.

pane 1. A flat sheet of glass, cut to fit a window or door or part of a window or door; often of small size, the larger ones usually being called sheets. After installation in a window sash, a pane is often referred to as a light. A window sash may be divided into a number of small lights, often for decorative or stylistic purposes. The configuration of a double-hung window having divided lights is often specified by the number of panes in the upper sash followed by the word over and then the number of panes in the lower sash; for example, a “six-over-three pattern” indicates that the upper sash is divided into six panes and the lower sash is divided into three panes. 2. A panel of a door, wainscot, or the like. 3. A rectangular division or plane surface of a building. 4. A British term for peen.

panel 1. A large, relatively thin board or sheet of lumber, plywood, or other material used as a wall covering. 2. A thin board, plywood sheet, or similar material with all its edges inserted in a groove of a surrounding frame of thick material. 3. A portion of a flat surface recessed or sunk below the surrounding area, distinctly set off by molding or some other decorative device. 4. A section of floor, wall, ceiling, or roof, usually prefabricated and of large size, handled as a single unit in the operations of assembly and erection. 5. A length of formed metal sheet, or an assembly of such sheets, usually with insulation between, as used for wall enclosure on industrial-type buildings. 6. A frog. 7. That portion of a truss between adjacent panel points lying in the same chord. 8. Same as panelboard.

panel board 1. In an electrical installation, a single panel or group of panel units designed for assembly in the form of a single panel; includes buses, and may include switches as well as automatic overcurrent protective devices for the control of electric circuits; designed to be placed in a cabinet or cutout box placed against a wall or partition so that it is accessible from the front only. 2. See control board.

panel box A small panel board providing many of the same functions as a larger panel board.

panel construction, panellized construction A method of building construction which uses panels as major elements or components.

panel divider A molding which separates two wood panels along their common edge.

panel door A door having stiles, rails, and sometimes mutins which form one or more frames around (thinner) recessed panels. (See illustration p. 700.)

paneled door Same as panel door.

panelescent lamp See electroluminescent lamp.

panel heating A system for heating a room or space by panels (in the walls, floor, ceiling, or along the baseboard) in which there are electric heating elements, hot-air pipes, or hot-water pipes.

panel house A brothel in which the rooms are lined with sliding panels which facilitate robberies of house patrons.

paneling A wall or ceiling treatment made up of panels, 4.

panel insert A metal panel usually used to convert a half-glass recessed panel-type door to an all-metal unit.

panel lamp A small lamp or a luminaire used to provide local lighting on instrument panels and the like.

panel length In a truss, the distance between two adjacent joints along either the upper or the lower chord.

panel lining 1. Door lining having panels similar to those on the door. 2. Lining around a window frame which matches the sash paneling.

panel load The load at a panel point of a truss.

panel mold See pan mold.

panel molding A molding surrounding a panel. See also bolection molding, drop molding.

panel pin A very slender wire nail with a small head; usually used in finished work.

panel point, node A point where members of a truss intersect.

panel radiator A radiator which is set into a wall panel or baseboard.

panel saw A small saw having closely set teeth; used in cutting thin panels and the like.

panel strip A narrow piece of metal or wood used to conceal a joint between two sheathing boards forming a panel.

panel tracery Same as perpendicular tracery.

panel wall A non-load-bearing wall between columns or piers in skeleton construction; such walls are supported at each story by the building frame.

panelwork Same as paneling.

panework 1. In Tudor Revival, the decorative panels formed by half-timbering. 2. Same as pane, 3.

pan fraction In the sieve analysis of aggregate, soil, etc., that fraction of the total sample retained on any sieve compared with the initial sample tested.

panhead rivet A rivet having a head whose shape is that of a truncated cone.

panic bolt See panic exit device.

panic exit device, fire-exit bolt, panic bolt, panic hardware A door locking device used on exit doors; the door latch releases when a bar, across the inside of the door, is pushed.

panic hardware See panic exit device.

panic latch See panic exit device.

panic switch An electric switch that controls a security lighting system in a home; often located in the master bedroom.

panier See corbeil.

pan mixer See open-top mixer.

pan mold, panel mold A mold used to cast plaster panels.

pannier Any basketlike architectural member, once especially applied to capitals resembling baskets.

panopticon A building (often a jail) planned with corridors which radiate from a single, central point. A person located at the central point can observe each of the converging halls.

panorama A building containing an exhibit of an extended pictorial representation of landscape or some event of note; usually depicted of a large, wide area.

pantheon 1. A temple dedicated to all the Gods. 2. (Cap.) The Rotunda in Rome, formerly a temple to all the gods, now a church. 3. The Pantheon in Paris, the former church of Sainte-Geneviève, now a shrine to national heroes.

pantile A roofing tile which has the shape of an S laid on its side.

pantograph A drafting instrument for copying drawings, plans, etc., either on the same scale or on an enlarged or a reduced scale.

pantry 1. A serving room between kitchen and dining space. 2. A room for storage of food supplies; a larder. 3. A room for preparing refreshments, not complete meals.

pan-type humidifier A shallow pan having a relatively large area, filled with water which evaporates as air passes over the pan; a heating element in the pan may be used to increase evaporation.

pan-type tread A section formed from sheet metal to receive a fill and to provide, when filled, either a tread or a combination tread and riser.

pap A downward outlet from an eaves gutter.

paper-backed lath Any lath having a paper backing.

paper felt A type of building paper.

paper form A form for concrete made of a heavy paper material.

papier-mâché A material composed principally of paper; usually prepared by pulping a mass of paper (sometimes glue is added) to a dough-like consistency and molding to a desired form.

papyriform A capital of an Egyptian column having the form of a cluster of papyrus flowers.

papyrus column A column having a papyriform capital.

p.a.r. Abbr. for “planed all round.”

PAR See PAR lamp.

PAR. On drawings, abbr. for paragraph.

parabema Same as diaconicon.

parabolic arch An arch similar to a three-centered arch but whose intrados is parabolic, with a vertical axis.

parabolic reflector A light reflector whose surface is a paraboloid, i.e., a surface generated by rotating a parabolic section about its axis; if a small light source is placed at the focal point of the reflector, the reflected light will be concentrated in a nearly collimated beam parallel to the axis of the reflector.

parabolic vaulting A type of vaulting, parabolic in shape, usually constructed of a relatively thin, lightweight, reinforced concrete; not subject to tensional stresses under conditions of uniform loading.

paracyl reflector A cylindrical light reflector whose cross section is that of a semicircle joined to part of a parabola; they are joined so that the focus of the parabola is the center of the semicircle, at which point a linear light source is placed; esp. used for wall-washing.

paradise 1. The court of the atrium in front of a church. 2. The garth of a cloister. 3. A Persian pleasure garden, usually elaborately planted.

paradisus Same as paradise.

parados 1. An entrance to the orchestra, 1 of a Greek theater. 2. Earthworks behind a fortified place.

paragraph In the AIA documents, the first subdivision of an article, identified by two numerals, e.g., 3.3; may be further subdivided into subparagraphs and clauses.

parallel-blade damper A damper, 1 through which the airflow is adjusted by means of damper blades on a common linkage, arranged so that adjacent blades rotate parallel to each other, providing little control of airflow; used primarily as an on-off control.

parallel-chord truss See flat-chord truss.

parallel coping A coping which is flat, not sloped to shed water.

parallel gutter See box gutter.

parallel stair A stair consisting of flights which parallel each other and are separated only by one or more intermediate platforms.

parallel-wire unit In posttensioning, a tendon which is composed of a number of strands (or wires) that are approximately parallel.

parapet 1. A low guarding wall at any point of sudden drop, as at the edge of a terrace, roof, battlement, balcony, etc. 2. A defense wall. 3. In an exterior wall, fire wall, or party wall, the part entirely above the roof.

parapeted gable A gable having a face that rises above the cornice line and carries a parapet; for examples, see corbie gable, Flemish gable, mission gable, multicurved gable, straight-line gable.

parapet gutter A gutter which is constructed behind a parapet wall.

parapet skirting Roofing felt which is turned up against a parapet wall.

parapet wall That part of a wall which is entirely above the roof.

para red A class of organic red and maroon dyes and pigments; used in paints.

parascenium A wing-like projection extending forward, at the ends of the skene, in ancient Greek theaters.

paraskenion Same as parascenium.

parastas 1. The end of a wall, terminating in an anta, such as that enclosing the pronaos of a temple. 2. A pedestal-like wall, as the abutment of the end of a monumental stairway.

paratorium The place at the east end of a basilican church, usually on the north side, for the offerings; in some Greek churches, located on the south side.

paratory In a church, a place where any preparation is made; a vestry or sacristy.

parcel Of land, a contiguous land area which is considered as a unit, which is subject to a single ownership, and which is legally recorded as a single piece.

parclose, perclose 1. In medieval churches and derivatives, a screen dividing a special space from general space. 2. The parapet round a gallery.

parecclesion A chapel of a Byzantine church.

parent material The material from which a soil has been formed.

paretta Rough-cast masonry having a surface of protruding pebbles.

parge To apply a parge coat; also see parget, 3.

parge board Same as bargeboard.

parge coat, pargeting, pargework 1. Elaborate plasterwork; especially an ornamental facing for plaster walls decorated with figures in low relief. 2. The interior lining of a chimney flue used to improve its fire protection and to provide a smooth surface. 3. A coat of cement mortar on the face of rough masonry construction.

parget, pargeting, pargetting, parge-work, parging 1. Elaborate plasterwork; esp. an ornamental facing for plaster walls, sometimes decorated with figures in low relief or indented; often used on the exterior of houses in the Tudor period. 2. An interior lining of a flue to provide a smooth surface and to aid in fire protection. 3. In masonry construction, a coat of cement mortar (generally containing dampproofing ingredients) on the face of rough masonry, the earth side of foundation and basement walls, or the like; a parge coat.

Parian cement, Parian plaster Similar to Keene’s cement, but contains borax as an additive in place of alum.

paries In ancient Roman construction, a wall of a house or other edifice. Also see murus.

paring Trimming or reducing in size or thickness, by cutting or shaving of small portions from the surface or extremity.

paring chisel A long-handled chisel used for cutting away wood by hand alone, not by striking with a mallet.

paring gouge A long, thin, concave gouge for woodworking which is beveled on its inner edge.

Paris blue See Prussian blue.

parish house A building for the secular activities of a parish.

Paris white Same as whiting.

park An area, usually of public land set aside for recreation and leisure, usually owned and managed by a municipality, a state, a nation, or held by royal grant, or in some cases by private organizations.

parkerized Descriptive of iron or steel which has received a rustproofing treatment by being dipped in a boiling solution of manganese dihydrogen phosphate; this protective coating also improves the bonding of paints and lacquers.

Parker’s cement Same as Roman cement.

Parker truss A type of truss whose upper chord, 1 is polygonal in form.

parking garage A garage for passenger vehicles only, exclusively for the purpose of parking or storing of automobiles and not for automobile repairs or service work.

parking lot, car park An area set aside for parking motor vehicles. The net area of a parking facility is the area devoted to parking places and circulation aisles. In a multi-story parking facility the gross area also includes the building’s service cores and exit stairs.

parking space A marked-off portion of a parking area for short-time storage of a single motor vehicle.

parking structure 1. A building for short-term storage of motor vehicles, having two or more tiers or levels and at least two open sides, and with the top tier either roofed or not. 2. A machine for automatic short-term storage of motor vehicles.

parking tier One of several levels or stories devoted to the temporary storage of motor vehicles.

PAR lamp A reflector lamp, usually incandescent, with a thick glass envelope, the back interior side of which has a parabolic shape with a reflective coating; used with a lensed front of the envelope to provide desired spread of the light beam.

parlatory A room in a monastic establishment where visitors may be received.

parliament hinge See H-hinge.

parlor 1. In a house, a room primarily for entertaining and conversing with guests. 2. In a hotel, a room for receptions.

parlor chamber A bedroom above the parlor in a two-story house having a hall-and-parlor plan.

parodos One of the two side entrances to an ancient theater between the seats and the stage; used principally by the chorus, but also by the public.

parpend A little used synonym for perpend.

parpend stone See perpend.

parquet 1. Inlaid wood flooring, usually set in simple geometric patterns. 2. Same as parquetry. 3. The lower floor of a theater, or the section of seats in an opera house, music hall, or theater extending from the musicians’ area to the parquet circle.

parquet circle, orchestra circle, parterre In a theater or opera house, the part of the main floor at the rear of the parquet, 3, usually under the galleries or balconies.

parquetry A flat inlay pattern of closely fitted pieces, usually geometrical, often employing two or more colors or materials; used for ornamental parquet flooring or wainscoting, in stone or wood.

parquet strip flooring Same as strip flooring.

parrel, chimney breast A chimneypiece or the ornaments of a chimneypiece collectively.

parsonage The residence of a parson, provided by the church.

part Abbr. for partition.

parterre 1. See parquet circle. 2. An ornamental arrangement of flower or gravel beds of various sizes and shapes.

Parthenon 1. Originally, the room behind the cella in the great temple of Athena Parthenos on the Athenian Acropolis. 2. More commonly, the name of the entire temple.

Parthian architecture An architectural style developed under Parthian domination (3rd cent. B.C. to 3rd cent. A.D.) in western Iran and Mesopotamia, combining classical with autochthonous features. Its major achievement is the monumental iwan covered by a barrel vault in stone or brick.

parti A scheme or concept for the design of a building.

partial cover plat e A cover plate, 1 attached to the flange of a girder which does not extend the full distance between the supports of the girder.

partial-height partition In an open-plan office, a free-standing partition which provides visual privacy and some (but usually little) sound attenuation between adjacent offices.

partial occupancy Occupancy by the owner of a portion of a project prior to final completion.

partial partition See partial-height partition.

partial payment A progress payment.

partial prestressing The prestressing of concrete to a level of stress such that tensile stresses exist in the precompressed tensile zone of the prestressed member, for design loads, 1.

partial release In a prestressed concrete member, a release of part of the total prestress initially held entirely in the prestressed reinforcement.

particleboard A large class of building boards made from wood particles and a binder; usually has a density of 25 to 50 lb per cu ft (400 to 800 kg per cu m); often faced with veneer. Also see chipboard; coreboard.

particle shape The shape of a particle of aggregate. Also see angular aggregate, cubical aggregate, elongated piece, flat piece.

particle size 1. In evaluating the efficiency of a filter for removing particles from an air stream, the minimum particle diameter in microns that will be removed by the filter. 2. In paints, the diameter of a pigment or latex particle; usually expressed in mils or microns.

particle-size distribution A tabulation of the percentages of the various sizes of particles in a sample of soil or aggregate for concrete as determined by sieve analysis.

particulate grout A grouting material which is characterized by undissolved particles in the mix.

parting agent A material applied to one or both surfaces of a sheet to prevent adhesion to other sheets; a release agent.

parting bead A long narrow strip between the upper and lower sashes in a double-hung window frame, enabling them to slide past each other; also called parting stop, parting strip.

parting compound A parting agent.

parting lath A parting strip made of wood lath.

parting slip, midfeather, wagtail A long thin strip of wood in the box jamb of a cased frame which separates the sash weights from each other; also called a parting strip, parting bead.

parting stop See parting bead.

parting strip 1. A narrow strip used to keep two parts separated, such as a parting slip. 2. A parting bead.

parting tool, V-tool A narrow-bladed hand tool having a V-shaped gouge; used in woodworking for cutting grooves, in wood turning, or for cutting pieces in two.

parting wall Same as party wall.

partition 1. A dividing wall within a building; may be bearing or non-load-bearing. 2. In sound-transmission considerations, any building component (or a combination of components), such as a wall, door, window, roof, or floor-ceiling assembly, that separates one space from another.

partition block A concrete masonry unit for use in non-load-bearing walls; usually has solid, rectangular end faces and a nominal thickness of 4 in. (10 cm) or 6 in. (15 cm).

partition cap, partition head, partition plate The uppermost horizontal member of a partition; the top plate of a partition on which the joists rest.

partition head See partition cap.

partition infilling 1. Same as fill insulation. 2. See infilling.

partition plate See partition cap.

partition stud See stud.

partition tile Tile for use in building interior partitions, subdividing areas into rooms, or similar construction, carrying no superimposed loads.

partly cloudy sky In daylighting, a sky having between 30% and 70% cloud cover.

partn Abbr. for partition.

parts per million The parts of a substance per million parts (by weight) of a solution; equal to 0.0001%. Abbr. ppm.

party arch An arch on the line separating the property of two owners.

party fence A fence that separates two properties.

party wall A wall used jointly by two parties under easement agreement, erected upon a line dividing two parcels of land, each of which is a separate real estate entity; a common wall.

party-wall house Same as row house.

parvis 1. The open square in front of a large church. 2. An enclosed court or room in front of a church. 3. A room over a church porch,1.

pascal (Pa) The Standard International unit of pressure; 1 pascal is equal to 1 newton per square meter.

pas-de-souris In a castle, the steps leading from the moat to the entrance.

pass A single progression of a welding operation along a joint, resulting in a weld bead.

PASS. On drawings, abbr. for “passenger.”

passage grave, chamber tomb In prehistoric Europe, a chamber approached by a long passage, of megalithic construction, covered and protected by an artificial mound.

passageway, passage A space connecting one area or room of a building with another.

pass door A door through the proscenium wall, from stage to the auditorium.

passenger elevator An elevator exclusively for the use of passengers. Also see freight elevator.

passenger elevator car See elevator car.

passenger lift See elevator car.

passings The amount of overlap between sheets of flashing etc.; same as lap, 2.

passion cross Same as Calvary cross.

passivation Treatment of a metal surface which leaves a protective coating, rendering the surface less reactive chemically.

passive lateral pressure The horizontal soil pressure that is exerted upon a retaining structure by the soil that it retains.

passive solar energy system A building subsystem in which solar energy is collected and transferred predominantly by natural means; uses natural convection, conduction, or radiation to distribute thermal energy through a structure, within the limits of the indoor design temperature conditions. Compare with active solar energy system.

pass-through 1. An opening in a partition for passing things from one adjoining space to another, usually between a kitchen and a dining space in a dwelling, but also between any two spaces in a building. 2. A provision in a lease that makes the tenant, rather than the owner, directly responsible for certain costs.

paste filler In painting, a filler, 3 in paste form; usually thinned with solvent prior to application.

paste paint A mixture of oil, pigment, and some solvent in paste form; requires mixing with additional solvent and/or oil to produce a usable paint.

pastiche A mixture of materials, forms, motifs, and/or styles; often incongruous.

pastophorium, pastophorion In the early church, one of the two apartments at the sides of the bema or sanctuary; this arrangement has been retained in the modern Greek Orthodox church.

pastoral column A tree trunk used as a column, for example, as used in cottage orné.

Pat. In the lumber industry, abbr. for “pattern.”

pat As applied to a specimen of neat cement paste, a sample about 3 in. (7.6 cm) in diameter and ½ in. (1.3 cm) in thickness at the center and tapering to a thin edge; applied on a flat glass plate to determine the setting time.

patand See patten.

patch 1. In stone masonry, a compound used to fill natural voids or to replace chips and broken corners or edges in fabricated pieces of cut stone; applied in plastic form; mixed or selected to match the color and texture of the stone. 2. In carpentry and joinery, a piece of wood or veneer glued into a recess to replace defective portions or voids; an insert or plug.

patch board, patch panel A board or panel where electric circuits are terminated with jacks and plugs, and where they may be interconnected temporarily by means of a cord called a “patch cord.”

patch panel See patch board.

patent board A building board manufactured under a patented process.

patent glazing A system of glazing which employs any of a variety of commercially available devices for securing the glass sheets without the use of putty.

patent hammer A two-faced hammer, each of whose faces is composed of a number of parallel thin chisels; used for dressing stone.

patent knotting In painting, a knot sealer; a solution of shellac and benzine or similar solvent. Also see knotting.

patent light Same as pavement light.

patent plaster 1. A gypsum plaster that is mixed with sand; used as a base-coat plaster. 2. A plaster manufactured under a patent process whose exact constituents are secret; a chemical plaster. 3. Same as cement plaster.

patent plate Same as plate glass.

patent stone See artificial stone.

patera A roundel, often decorated with leaves, petals, or the like; sometimes used as a decorative element, such as on a corner block. Also see rosette.

paternoster A small round molding cut in the form of beads like a rosary; a bead molding.

path A footway; a footpath.

patience Same as miserere.

patin See patten.

patina, patination 1. A greenish brown crust which forms on bronze. 2. Any thin oxide film which forms on a metal; often multicolored. 3. A film, similar in color, which forms on a material other than metal. 4. Such effects artificially induced, or imitated. 5. A green coating on the surface of copper or copper alloys that have been exposed to the atmosphere for a long time.

patio 1. An outdoor area or courtyard, open to the sky but enclosed, or partially enclosed, by the walls of a building. Although the term originally described such an area in a Spanish house, it is now widely used for any outdoor recreational space that is adjacent to a house; also see placita. 2. A large quadrangle of an early Spanish-American mission, usually surrounded on all four sides by a series of abutting structures for protection.

patland In carpentry of the Early English period, the sill or lower frame member.

patten, patand, patin 1. The base of a column or pillar. 2. A base or a groundsill which supports a column, post, or pillar.

pattern 1. A model made in some easily worked material (such as plaster or wood) which serves as a guide, with respect to form and dimensions, in laying out any piece of work, esp. to preserve and secure uniformity and accuracy. 2. A design, considered as a unit, of which an idea can be given by a fragment, as a diaper pattern. 3. In molding, a form used to provide the interior shape of the mold.

pattern book In the 18th and 19th centuries, a book on architectural practice that once served as a builders’ manual, builders’ guide, or handbook containing plans and/or patterns of houses and building details such as columns, cornices, doors, porches, and windows.

pattern cracking Fine openings on concrete surfaces in the form of a pattern; results from a decrease in volume of the material near the surface and/or an increase in volume of the material below the surface.

patterned brickwork Masonry of bricks of more than one color, direction, texture, or bond, 6, so as to form a decorative design.

patterned glass Glass that has a textured pattern on one side (the other side being smooth).

pattern staining In plastering, dark areas, particularly on the interior side of exterior walls or ceilings; results from different thermal conductances of the backings.

paumelle A type of door hinge having a single joint of the pivot type, usually of modern design.

pavement The durable surfacing of a road, sidewalk, or other outdoor area.

pavement base In a pavement, the layer between the surfacing material and the subbase or subgrade.

pavement brick A square paving brick that is relatively thin.

pavement light Heavy glass disks or prisms set into a pavement to convey light to a space beneath.

pavement saw A self-propelled machine, equipped with a rotating blade, that cuts a narrow kerf in a new concrete slab to provide a localized joint for the control of cracking due to expansion.

pavement sealer See asphalt pavement sealer.

pavement structure All courses of selected material placed on a foundation or subgrade soil, other than layers or courses constructed in grading operations.

paver 1. A paving stone, paving brick, or paver tile. 2. A half-thickness paving brick, used as a floor finish. 3. A self-propelled machine that places concrete.

paver tile Unglazed porcelain or natural clay tile, formed by the dust-pressed method; similar to ceramic mosaic tile in composition and physical properties but thicker.

pavestone A paving stone.

pavilion 1. A detached or semidetached structure used for entertainment or (as at a hospital) for specialized activities. 2. On a façade, a prominent portion usually central or terminal, identified by projection, height, and special roof forms. 3. In a garden or fairground, a temporary structure or tent, usually ornamented.

pavilion roof 1. A roof hipped equally on all sides, so as to have a pyramidal form; a pyramidal hipped roof. 2. A similar roof having more than four sides; a polygonal roof. 3. A steeply pitched hipped roof whose upper termination is usually a ridge somewhat shorter than the length of the building.

pavimentum In ancient Roman construction, a pavement formed by pieces of crushed stone, flint, tile, and other materials set in a bed of ashes or cement and consolidated by beating down with a rammer.

paving aggregate Materials such as crushed stone, gravel, sand, slag, seashells, and mineral dust, used in pavements.

paving asphalt A dark brown to black sticky residue, predominantly derived from the refining of crude oil; used as the binder in asphaltic concrete.

paving breaker, chipper A hand-held compressed-air-powered tool for cutting pavement or rock; delivers repetitive blows by means of a pointed or chisel-shaped bit.

paving brick A vitrified brick, esp. suitable for use in pavements where resistance to abrasion is important; a pavior.

paving stone, pavestone A block or chunk of stone, shaped or selected by shape for a paved surface.

paving train An assemblage of equipment designed to place and finish a concrete pavement.

paving unit Any prefabricated unit used for surfacing the ground.

pavior, paviour 1. A brick used for paving. 2. A clamp brick of second quality which is hard, well-shaped, and of good appearance and color.

pavonaceum An ancient method of laying tiles that are rounded at one end, so that in overlapping each other they present a scalloped appearance.

pavonazzo, pavonazzeto 1. Various red and purplish marbles and brescias. 2. A marble, used by the ancient Romans, characterized by very irregular veins of dark red with bluish and yellowish tints.

pawn A covered passageway or gallery.

PAX On drawings, abbr. for “private automatic (telephone) exchange.”

payment bond A form of security purchased from an insurance company, which provides a guarantee that the contractor will pay the complete costs of labor, materials, and other services related to the project for which he is responsible under the contract for construction.

payment request See application for payment.

payments withheld A provision in the General Conditions of a contract for construction that permits the owner to withhold payments to a contractor if the work specified in the contract documents falls behind the schedule of construction or if the work deviates from the specifications.

PB stucco Abbr. for polymer-based stucco.

PBX See private branch exchange.

pc Abbr. for “piece.”

PC 1. Abbr. for portland cement. 2. Abbr. for “power circuit.” 3. On drawings, abbr. for “piece.” 4. On drawings, abbr. for “pull chain.” 5. Abbr. for “Producers Council.”

PCA Abbr. for “Portland Cement Association.”

pcf Abbr. for “pounds per cubic foot.”

PC stucco Abbr. for portland cement stucco.

PCSA Abbr. for “Power Crane and Shovel Association.”

p.e. Abbr. for “plain edged.”

PE 1. In the lumber industry, abbr. for “plain end.” 2. Abbr. for polyethylene.

P.E. Abbr. for professional engineer.

peacock’s-eye Same as bird’s eye.

pea gravel Small-diameter (¼ to

in. or 6.4 to 9.5 mm) natural gravel, screened to specification.

pea gravel grout A grout to which pea gravel has been added.

peak arch A pointed arch.

peak demand The maximum rate of consumption of water or electric power that a utility provides a customer.

peaked roof A roof of two or more slopes that rises to a ridge or peak.

peak-head window 1. A window that has a triangular head, such as a lancet window ; often found in Gothic Revival church architecture. 2. Same as lancet window.

peak joint At the ridge of a roof, the joint between members of a roof truss. (See illustration p. 710.)

peak load The maximum load carried by a device, system, or structure over a designated time period.

peak-load controller An automatic electrical monitor and controller which can be used to limit the maximum power demands of a building.

peak sound pressure The maximum instantaneous sound pressure (a) for a transient or impulsive sound of short time duration, or (b) for a sound of long duration, over a specified time interval.

pean See peen.

peanut gallery The topmost balcony in an auditorium.

pear drop 1. A pear-shaped pendant, often used as a handle or support. 2. In 18th cent. architecture, a support for a small arch.

pearl essence A translucent, lustrous pigment obtained from fish scales or compounded synthetically; used as a pigment in lacquers to obtain a pearl-like finish.

pearlite Same as perlite.

pearl lamp British term for a frosted lamp bulb which is etched on its inner surface.

pearl molding A molding decorated with a continuous series of pearl-like shapes.

peat A fibrous mass of organic matter in various stages of decomposition, generally dark brown to black in color and of spongy consistency.

peat moss 1. Moss entering into the composition of, or producing, peat; used as mulch. 2. The debris of mashes and bogs, somewhat compressed and partially decomposed; used as mulch.

pebble dash Same as rock dash.

pebble wall 1. A wall built of pebbles in mortar. 2. A wall faced with pebbles embedded, at random or in pattern, in a mortar coating on the exposed surface.

peck In timber, decay resulting from fungus in isolated spots.

pecked finished Same as picked finish.

pecking Same as salmon brick.

pecky timber, peggy timber Fungus-spotted wood, such as pecky cypress or pecky cedar; the decay stops when the wood is dried.

pectinated Having teeth like a comb.

pedestal 1. A support for a column, statue, urn, etc., consisting in classical architecture of a base, dado, or die and a cornice, surbase, or cap; in modern design often a plain unornamented block. 2. An upright compression member the height of which does not exceed three times its least lateral dimension.

pedestal pile A cast-in-place pile which is constructed so that some concrete is forced out at the bottom of the casing, forming a pedestal shape at the foot of the pile.

pedestal urinal A urinal which is not connected to the wall for support but is mounted on a single pedestal.

pedestal washbasin A washbasin which is supported from the floor by a column-like base.

pedestrian bridge See footbridge.

pedestrian control device Any device, esp. a turnstile, but including a gate, railing, or post, used to control or monitor the flow of pedestrian traffic, to control access to a given area, etc.

pede window In a church, a window oriented with respect to a larger one so as to symbolize one of the feet of Christ.

pediment 1. In Classical architecture, a triangular gable usually having a horizontal cornice, with raked cornices on each side, surmounting or crowning a portico or another major division of a façade, end wall, or colonnade. 2. A gable above or over a door, window, or hood; usually has a horizontal cornice, crowned with curved sides, or may also be crowned with another configuration (such as broken sides) or its base may be broken in the middle. For definitions and illustrations of specific types, see angular pediment, broken pediment, broken-scroll pediment, center-gabled pediment, curved pediment, open pediment, pointed pediment, round pediment, scroll pediment, segmental pediment, split pediment, swan’s-neck pediment, triangular pediment.

pediment arch A miter arch.

peel, pele In northern England and Scotland in the Middle Ages, a small, emergency defense structure, generally a low, fortified tower, usable as a dwelling place.

peeling 1. A process in which thin flakes of mortar are broken away from a concrete surface, as by deterioration or by adherence of surface mortar to forms as they are removed. 2. A defect in a paint film or plaster finish which causes the film or finish to lose its adhesion to the substrate, so that it can be removed in strips.

peel tower Same as peel.

peen, pean The end of a hammer opposite the flat hammering face; may terminate in a cone-shaped, rounded, or sharply pointed face.

peen-coated nail See mechanically galvanized nail.

peening The working of a metal by means of hammer blows.

peg 1. A pointed pin of wood, metal, or any other material; usually used as a fastener. 2. A cylindrical piece of wood used as a dowel pin to fasten wood members.

pegboard, perforated hardboard A hard composition fiberboard material in sheet form, usually about ¼ in. (0.6 cm) thick, having regular rows of holes in it, through which hooks or pegs may be fastened.

peggies Slates of random length and width.

peggy timber Same as pecky timber.

pegma 1. Any ancient construction material made of boards that are joined together. 2. A machine used in a Classical Roman amphitheater to facilitate a quick change of scenery on the stage.

peg mold A running mold.

peg stay A type of casement stay used to hold a casement, 1 open.

pein Same as peen.

pele Same as peel.

pellet 1. Any small, round, decorative projection; usually one of many. 2. A circular wood plug which covers a countersunk screw.

pellet molding A molding decorated with a series of small, flat disks or hemispherical projections.

pelmet A valance or cornice, sometimes decorative, built into the head of a window to conceal the drapery track or blind brackets or fittings.

pelmet board A board, at the head of the interior side of a window, which acts as a pelmet.

pelmet lighting See valance lighting.

pen 1. A synonym for room in a four-sided enclosure constructed of logs. Thus, a one-room log cabin is often called a single-pen cabin, and a dogtrot cabin (consisting of two single-room cabins) is often called a double-pen cabin. 2. An enclosure for animals; for example, a pigpen.

penal sum The amount named in a contract or bond as the damages or penalty to be paid by a signatory thereto in the event he fails to perform his contractual obligations or does not do so within the time prescribed by the contract.

penalty-and-bonus clause See bonus-and-penalty clause.

penalty clause A contract provision setting forth the damages a party must pay in the event of his breach. If such a clause is regarded by the court as too harsh to be regarded as a fair estimate of probable damages, it will normally be held invalid. See liquidated damages.

penciled Descriptive of a mortar joint in a brick wall used in the early 19th century when extremely thin mortar joints were fashionable. They were prepared as follows: First, the wall, with mortar joints flush with the brick surface, was painted the color of the brick; then a narrow white line painted along the center of the mortar joints.

pencil rod Any rod having a diameter approximating that of a lead pencil.

pendant newel Same as newel drop.

pendant, pendent, pendent drop 1. A suspended feature or hanging ornament used in the vaults and timber roofs of Gothic architecture or Gothic Revival; also called a pendent. 2. A carved or turned wood ornament that terminates the bottom end of second-floor posts in framed overhang construction, also called a drop or corner drop; or such an ornament on each side of the front door. 3. An electrical device or piece of equipment that is suspended from overhead by means of a flexible cord carrying the current.

pendant luminaire A suspended luminaire.

pendant post In a hammer-beam roof, the lower post at the foot of the truss.

pendant sprinkler A sprinkler in a fire-protection system designed in which the water stream is directed downward against a deflector disk, developing a spray pattern.

pendant switch An electric wiring switch which is suspended from overhead at the end of a two-conductor cord; used to control lamps or other devices that are mounted overhead, beyond the reach of a person standing on the floor.

pendent Same as pendant.

pendentive 1. One of a set of curved wall surfaces which form a transition between a dome (or its drum) and the supporting masonry. 2. In medieval architecture and derivatives, one of a set of surfaces vaulted outward from a pier, corbel, or the like.

pendentive bracketing Corbeling in the general form of a pendentive; common in Moorish and Muslim architecture.

pendentive cradling The curved ribs in arched and vaulted ceilings, used to carry or support the plasterwork.

pendent post, pendant post 1. In a medieval principal roof truss, a short post placed against the wall, its lower end supported on a corbel or capital, and its upper end carrying the tie beam or hammer beam. 2. The support of an arch across the angles of a square.

pendent sprinkler A fire sprinkler (i.e., sprinkler head) designed to be installed below the piping in a sprinkler system; the water stream discharged by the head is directed downward against a deflector (a flat-toothed disk) that develops the sprinkler spray pattern.

pendice See penthouse.

pendiculated Supported by a pendicule.

pendicule A small pillar which serves as a support.

pendill Same as pendant, 2.

pendulum saw See swing saw.

penetralia 1. The interior part of a building, as a sanctuary. 2. An inner apartment.

penetrating finish A low-viscosity oil or varnish which penetrates wood, leaving a very thin film at the surface.

penetration 1. The intersection of two vaulting surfaces. 2. The consistency of a bituminous material expressed as the distance (in hundredths of a centimeter) that a standard needle vertically penetrates a sample of the material under known conditions of loading, time, and temperature. Unless otherwise specified, the load, time, and temperature are understood to be 100 g, 5 sec, and 25°C (77°F), respectively.

penetration resistance 1. The resistance by a subsoil to penetration by pile, casing, or sampling device; measured by the number of blows of a hammer of specified weight, falling through a specified distance to drive it a specified distance. 2. See standard penetration resistance.

penetration test A test which measures the relative density of silt or sand at the bottom of a borehole. Also see dynamic penetration test and static penetration test.

penetrometer A device that measures the depth to which a standard needle penetrates a material under standardized conditions.

peninsula-base kitchen cabinet A kitchen cabinet which extends outward at right angles from a row of cabinets and has one exposed end.

Penn plan Similar to the Quaker plan, but having an interior chimney rather than an exterior chimney.

Pennsylvania Dutch The German-speaking immigrants and their descendants who settled in Pennsylvania primarily during the 18th century. For examples of their architecture, see bank barn, forebay barn, German Barn, hex barn, Pennsylvania Dutch barn, pfeiler, rauchkammer, springhouse.

Pennsylvania Dutch barn, Pennsylvania barn A two-story barn, built into the slope of a hill, whose upper structure overhangs the story below on the downhill side.

penny, penny-size 1. A unit denoting the length of a nail; for the common nail, and others which have been standardized, it also is an indication of the shank and head diameter. 2. (Abbr. d) A suffix indicating the size of a nail; the size specifies the length of the nail and the number of nails per pound, e.g., a 2d nail is 1 in. long and there are 875 per pound.

pent 1. Same as chimney pent. 2. Same as pent roof. 3. A small room, lean-to, or shed, often with one or more open sides.

pentachlorophenol A toxic, oil-soluble chemical; widely used as a wood preservative for protection against decay and insects.

pentacle In Gothic tracery a five-pointed star motif with a pentagon in the center.

pentastyle A term descriptive of a portico having five columns in front.

penthouse, pendice, pentice 1. A structure occupying usually less than half the roof area of a flat-roofed building, and used: (a) to house equipment for elevator, ventilation or air conditioning, or other mechanical or electrical systems serving the building, or (b) to house one or more apartments, access to which is gained by a stair or stairs, or a separate elevator but usually not by the building’s main elevators. 2. An appentice.

pentice 1. A small pent roof, 1 on a side of a building, often restricted to the area over a door. 2. See penthouse.

pent roof 1. A small eaves-like projection from the façade of a house between the first and second floors; has a single straight slope; may provide very limited shelter for a window or door directly below, but is usually merely decorative. Frequently called a visor roof ; also see skirt-roof. 2. Same as shed roof.

pepperbox A small cylindrical tower or turret resembling the shape of a pepperbox used to sprinkle ground pepper; often has a conical roof.

pepperbox turret A turret circular in plan and with some form of conical or domical roof.

peppermint test A scent test, in a plumbing system, using oil of peppermint as the source of odor.

pepper-pot A small turret having a peaked conical roof.

percentage agreement An agreement for professional services in which the compensation is based upon a percentage of the construction cost.

percentage fee Compensation based upon a percentage of construction cost. Also see fee.

percentage humidity The ratio of the weight of water vapor in a pound of dry air to the weight of water vapor that would be present if the same weight of air were saturated; the ratio is expressed as a percentage.

percentage reinforcement The ratio of cross-sectional area of reinforcing steel to the effective cross-sectional area of a member, expressed as a percentage.

percentage rental A rent paid by a tenant to an owner, usually comprising a minimum monthly payment plus a specified percentage of the value of business done by the tenant during the month.

percentage void The percentage of superficial area which is lost by holes, perforations, or cores.

percent fines 1. The percentage of material in aggregate finer than a given sieve, usually the 74-µm (No. 200) sieve. 2. The amount of fine aggregate in a concrete mixture expressed as a percentage, by absolute volume, of the total amount of aggregate.

percent saturation The ratio of the volume of water in a given soil mass to the total volume of intergranular space, expressed as a percentage.

percent voids See percentage void.

perch A unit of cubic measure used by stone masons; usually 16½ ft by 1½ ft by 1 ft (5.03 m by 0.46 m by 0.30 m).

perched water table A water table (usually of limited area) maintained above the normal free water elevation by the presence of an intervening relatively impervious confining strata.

perclose See parclose.

percolation The downward movement of water into soil.

percolation test A test to determine the rate at which a particular soil absorbs effluent ; a hole is dug in the soil and filled with water, then the rate at which the water level drops is measured. (See illustration p. 716.)

percussion drill A drill, 3, usually driven by compressed air, in which the drilling action is the result of a series of impacts transmitted by a drill rod to a drill bit.

perennial A plant or shrub whose life cycle is greater than 2 years.

PERF On drawings, abbr. for “perforate.”

perfect diffusion 1. (in lighting) The condition in which light flux is uniformly scattered in all directions so that the luminance (radiance) is equal in all directions. 2. (in room acoustics) The condition in which sound waves travel in all directions with equal probability so that the sound level of the reflected sound is equal throughout the room.

perfect six A three-story brick house having two families per floor and a central entrance; often has a Classical roof cornice.

perfection A long red cedar shingle having a butt thickness of

in. (1.4 cm).

perforated brick (Brit.) A brick or block in which holes passing through it exceed 25% of its volume, and in which the holes are not small (as defined under solid masonry unit, 2); up to three holes, not exceeding 5 sq in. (32.5 sq cm) each, may be incorporated as an aid to handling.

perforated facing In an acoustical assembly, any flexible or rigid perforated sheet or board designed as a protective surface allowing free access of sound to an underlying layer of sound-absorptive material.

perforated gypsum lath A gypsum lath which has perforations to provide mechanical keying of the base-coat plaster.

perforated hardboard See pegboard.

perforated metal Sheet metal usually having a regular pattern of perforations; available in many designs.

perforated metal pan, metal pan The exposed finish portion of an acoustical ceiling assembly, in which the metal pan contains and protects a separate pad or layer of sound-absorptive material.

perforated tape A type of tape used finishing joints between gypsum boards.

perforated tracery Same as net tracery.

perforated wall See pierced wall.

performance bond A bond of the contractor in which a surety guarantees to the owner that the work will be performed in accordance with the contract documents ; frequently combined with the labor and material payment bond ; except where prohibited by statute.

performance curve A graphic representation of an operating characteristic of a piece of equipment, such as a fan; shows how such a characteristic varies as a function of a single parameter (for example, volume flow rate vs. fan speed).

performance requirement A requirement that a material, device, piece of equipment, or a system must possess a stated characteristic.

performance specification A specification based on the performance required of a given assembly, component, device, equipment, or material. Often such a specification refers to relevant standards.

performance standard In building construction, a standard which defines the required performance of the building (taken as a whole) or of specified building components.

performance test A test to determine whether or not a given assembly, material, device, piece of equipment, or system meets its performance requirements.

perget Same as parget.

pergola 1. A garden structure with an open wooden-framed roof, often latticed, supported by regularly spaced posts or columns. The structure, often covered by climbing plants such as vines or roses, shades a walk or passageway. 2. A colonnade which has such a structure.

pergula Same as pergola.

periaktos In an ancient Greek theater, one of the two pieces of machinery placed on both sides of the stage for shifting scenes.

peribolus A sacred enclosure surrounding an ancient Classical temple.

periclase A crystalline mineral which is sometimes found in portland cement, portland cement clinker, and certain slags.

peridrome In an ancient peripteral temple, the open space or passage between the walls of the cella and the surrounding columns.

peridromos The narrow passage around the exterior of a peripteral building behind the surrounding columns.

periform Pear-shaped; said of a roof in the form of a pear (as some baptisteries and Eastern churches) or said of a molding having a pear shape.

perimeter beam A wood beam attached to the edges or exposed ends of floor joists.

perimeter bracing A vertical bracing element that is located at the perimeter of a building; also called peripheral bracing.

perimeter drain A drain at the base of a foundation wall that carries water away from it.

perimeter/floor ratio On a typical floor of a building, the total length of a floor’s perimeter divided by the enclosed floor area.

perimeter grouting Grouting, at relatively low pressure, around the perimeter of an area which is subsequently grouted at a higher pressure.

perimeter heating system A warm-air heating system in which the ducts are embedded in the concrete slab of a basementless house, around the perimeter of the rooms; heated air from the furnace is carried through the ducts to registers placed in or near the floor; air is returned to the furnace from registers near the ceiling.

perimeter raceway Same as baseboard raceway.

Period Revival Not a specific architectural style, but rather a term that usually denotes a historic revival of some architectural mode ; for examples, see Colonial Revival, Georgian Revival, Mission Revival, Pueblo Revival, Spanish Colonial Revival, Tudor Revival.

peripheral bracing Same as perimeter bracing.

periphery wall An exterior wall.

peripteral A term descriptive of a classical building that is surrounded by a single row of columns.

peripteros, periptery A building having a peristyle of a single row of columns.

peristalith A circle of upright stones surrounding a burial mound.

peristasis The ring of columns which encircles a peripteral building.

peristele One of the upright stones in a peristalith.

peristerium The inner or second ciborium.

peristyle 1. A colonnade surrounding either the exterior of a building or an open space, e.g., a courtyard. 2. The space so enclosed.

perithyride Same as ancon.

perling Same as purlin.

perlite A siliceous volcanic rock; under heat it expands to 15 to 20 times its original volume, forming an excellent lightweight aggregate; used in plaster or gypsum wallboard, as loose-fill thermal insulation, and as an aggregate in concrete.

perlite plaster Gypsum plaster which contains perlite as an aggregate instead of sand.

perlitic Said of a material having a structure similar to that of perlite.

perm A unit of water vapor permeance ; in US Customary units, 1 perm equals one grain of water vapor transmitted per one square foot per hour per inch of mercury pressure difference.

PERM On drawings, abbr. for “permanent.”

permafrost Permanently frozen soil, subsoil, or other deposits in arctic or subarctic regions.

permanence Of an adhesive bond, the bond’s resistance against deteriorating influences.

permanent bracing Bracing so designed and installed as to form an integral part of the final structure; may also serve as erection bracing.

permanent construction A term that usually encompasses construction at a job site other than the following: land preparation (such as clearing, grading, and filling); excavation for a basement, cellar, footings, foundations, or piers; erection of temporary forms; the installation on the property of accessory buildings such as garages or sheds not occupied as dwellings and not part of the main building.

permanent form Any concrete form that remains in place after the concrete has developed its design strength.

permanent formwork, permanent shuttering A type of formwork that remains in place after the concrete work has set.

permanent load The load which is permanently supported by a structure, such as the dead load or any fixed loads.

permanent seating In a place of assembly, seats that remain fixed in place for a specified minimum period of time; for example, for at least six months or more.

permanent set The change in length (expressed as a percentage of the original length) by which an elastic material fails to return to original length after being stressed for a standard period of time. Also see set.

permanent shore A dead shore.

permanent shuttering Permanent formwork which is left in place after the pouring of concrete so that it forms part of the structure.

permeability 1. The property of a porous material which permits the passage of water vapor through it. Also see permeance. 2. The property of soil, rock, or mantle which permits water to flow through it.

permeability test A test to determine movement through concrete of water under pressure.

permeameter An apparatus which measures the permeability, 2 of soils and other similar materials.

permeance A measure of a material’s resistance to water-vapor transmission, expressed in perms. Equal to the ratio of (a) the rate of water vapor transmission through a material or assembly between its two parallel surfaces to (b) the vapor pressure differential between the surfaces.

permissible stress Same as allowable stress.

permissible working load The working load that a structure is expected to sustain.

permit A document issued by a governmental authority having jurisdiction to authorize specific work by the applicant.

PERP On drawings, abbr. for “perpendicular.”

perpend, perpend stone A rectangular stone set with its longest dimensions perpendicular to the face of a masonry wall; extends through the entire thickness of the wall so that it is exposed on both faces of the wall.

Perpendicular style, Rectilinear style The last and longest phase of Gothic architecture in England, ca. 1350–1550, following upon the Decorated style and eventually succeeded by Elizabethan architecture. Characterized by vertical emphasis in structure and frequently elaborate fan vaults. Its final development (1485–1547) is often referred to as Tudor architecture.

perpendicular tracery, rectilinear tracery Tracery of the Perpendicular style with repeated perpendicular mullions often rising to the curve of the arch, the mullions crossed at intervals by horizontal transoms producing repeated vertical rectangles.

perpendiculum A plumb line, employed by ancient masons, bricklayers, etc.

perpend wall, perpeyn wall A wall built of perpends or of ashlar stones, all of which reach from one side to the other.

perpeyn Same as perpend.

perron 1. A formal terrace or platform, esp. one centered on a gate or doorway. 2. An outdoor flight of steps, usually symmetrical, leading to a terrace, platform, or doorway of a large building.

Persian A telamon, esp. one portrayed in Persian dress.

Persic column In Egyptian Revival architecture, a column having lotus ornamentation on a bell-shaped capital.

persienne An exterior louver window having adjustable slats.

person According to most codes : an individual, partnership, corporation, or other legal entity.

persona A mask of terra-cotta, marble, etc., designed to imitate the human face or the head of an animal, usually in grotesque form, employed as an antefix in buildings, as an ornament for discharging water, or as a gargoyle.

personal injury In insurance terminology, injury or damage to the character or reputation of a person, as well as bodily injury. Personal injury insurance usually covers such situations as false arrest, malicious prosecution, willful detention or imprisonment, libel, slander, defamation of character, wrongful eviction, invasion of privacy, and wrongful entry. Also see bodily injury.

personal property Movables and other property not classified as real property.

perspective 1. The technique of representing solid objects upon a flat surface. 2. A picture or drawing employing this technique.

perspective center The point of origin or termination of bundles of perspective rays.

perspective drawing A graphic representation of a project or part thereof as it would appear three-dimensionally.

perspective plane Any plane containing the perspective center.

perspective projection The projection of points by straight lines drawn through them from some given point to an intersection with the plane of projection.

PERT 1. Acronym for “project evaluation and review technique.” 2. See program estimation revaluation technique.

pertica In medieval churches, a beam behind the altar from which relics were suspended on festival days.

PERT schedule A PERT chart of the activities and events anticipated in a work process. Also see critical path method.

pervious cesspool See cesspool, 1.

pervious cover A vegetated area that allows rainfall to infiltrate the soil.

pervious soil A soil which allows relatively free movement of water.

pessulus A bolt for fastening a leaf of an ancient Roman door. These doors, usually having two leaves, had two (sometimes four) bolts fixed to them—one at the top and one at the bottom of each leaf.

petal One of the overlapping shingles or tiles in imbrication.

pet cock, draw cock A small valve installed in a piping system or on a piece of equipment to drain it or to release air pockets.

Petersburg standard See Petrograd standard.

Petit truss A modified form of the Pratt truss, having subdiagonals.

petrifying liquid 1. A low-viscosity penetrating solution of a waterproofing material for use on masonry surfaces. 2. An additive for distempers.

Petrograd standard A British unit of timber measure: 165 cu ft (4.67 cu m).

petrographic analysis A laboratory determination of the mineralogical and chemical character of rocks; by extension, an analysis of the constituents of concrete, yielding the approximate cement content.

petroleum asphalt Asphalt which is refined directly from petroleum; of two types, asphalt base and paraffin base.

petroleum hydrocarbon Any of a number of solvents obtained from crude petroleum; used to lower the viscosity of oils and resins contained in paints.

petroleum spirit See mineral spirit.

pew In a house of worship, one of a number of fixed benches with backs; also see box pew.

pfa Abbr. for British term pulverised-fuel ash.

PFD On drawings, abbr. for “preferred.”

pfeiler A pillar or pier that supports the forebay in a Pennsylvania Dutch barn.

ph Abbr. for phot.

pH A measure of the acidity or alkalinity of a solution; numerically equal to 7.0 for a neutral solution; the pH value increases with increasing alkalinity and decreases with increasing acidity. Also see pH value.

PH 1. On drawings, abbr. for “phase.” 2. Abbr. for Phillips head.

1PH Abbr. for “single phase.”

3PH Abbr. for “three phase.”

phantom line A broken line indicating an alternative position of delineated parts of an object, repeated detail, or the relative position of an absent part; usually a fine line of alternating long and short dashes.

phase One of the basic services provided by the architect as part of the professional services agreement between the architect and owner; divided into the following phases: schematic design, design development, construction documents, bidding (negotiation), and construction contract administration.

phased application The application of built-up roofing plies in two or more operations, usually at least one day apart.

phased construction Construction in which the stages of design and construction overlap, thereby shortening the time necessary to complete the project.

phenol A class of acid organic compounds used in the manufacture of epoxy resins, phenol-formaldehyde resins, plasticizers, plastics, and wood preservatives.

phenol-formaldehyde resin, phenolic resin A thermosetting, waterproof, low-cost, mold-resistant, high-strength synthetic resin made from phenol and formaldehyde; has good resistance to aging; used extensively in the manufacture of adhesives, exterior and marine plywood, laminated products, and molded articles.

phenolic foam A thermosetting foam plastic used to provide thermal insulation.

phenolic resin See phenol-formaldehyde resin.

Philadelphia leveling rod A two-piece leveling rod, with graduation marks so styled that it may be used as a self-reading leveling rod.

Philippine ebony See ebony.

Philippine mahogany, red lauan, white lauan The wood of trees of several genera found in the Philippines; not a true mahogany, but resembles true mahogany in grain; density ranges from very light to quite heavy; whitish-yellow to pink, brown, or dark red in color; the heavier, darker woods are generally durable and quite strong and are used like true mahogany; the lighter-weight, colored woods are used for interior carpentry, plywood, and general construction.

Phillips head A screw having a special head with crossed slots which are perpendicular to each other.

phon A unit of loudness level.

phosphated metal A metal surface which has been pretreated with hot phosphoric acid, to prepare it for receiving a finished coating.

phosphor A substance capable of luminescence, such as a fluorescent powder which absorbs ultraviolet power and reemits it as visible light; used to coat the inside of various electric-discharge lamps.

phosphorescence The emission of light as the result of the absorption of electromagnetic radiation; continues for a noticeable length of time after excitation.

phosphorescent paint See luminous paint.

phosphor mercury-vapor lamp A high-pressure mercury-vapor lamp consisting of an arc tube enclosed by a phosphor-coated glass envelope; the phosphor generates colors not produced by the arc.

phot A unit of illumination equal to 1 lumen per square centimeter. Abbr. ph.

photisterium Same as baptistery.

photoelectric cell A device incorporated in an electric circuit; in response to light that falls on the cell, the electrical output or the resistance varies; used in measuring devices and in control devices that depend on illumination level or the interruption of a light beam.

photoelectric control A control function which is actuated by a change in incident light.

photoelectric smoke detector A sensor used to initiate a fire alarm when smoke reduces the light received by a photoelectric cell in a device containing a light source; most effective in the early detection of fires in the smoldering stage.

photogrammetry The technology of obtaining reliable distance measurements by photograph.

photographing Same as telegraphing.

photometer Any instrument that measures photometric quantities such as luminance, luminous intensity, luminous flux, and illumination.

photometry The measurement of quantities associated with light.

photo sensor See photoelectric cell.

Phrygian marble Same as pavonazzo, 2.

phthalocyanine pigments Exceptionally durable, permanent green and blue pigments used in paints, enamels, and plastics.

pH value A number denoting the degree of acidity or of basicity (alkalinity); 7 is a neutral value; acidity increases with decreasing values below 7; basicity increases with increasing values above 7.

physical depreciation That depreciation in value of a building that results from aging, usage, and wear and tear.

physical disability, physical handicap Legally, any of the following handicaps: an impairment requiring the use of a wheelchair; an impairment causing difficulty or insecurity in walking or climbing stairs or requiring the use of braces, crutches, or other artificial supports; impairment (partial or total) of hearing or sight, causing likelihood of exposure to danger in public places; or impairment due to conditions of aging or incoordination. Also see Americans with Disabilities Act.

physical stability The ability of a product to maintain its physical dimensions and properties when exposed to conditions normally encountered in its service environment.

piache A covered arched walk, or portico.

piano hinge See continuous hinge.

piano nobile In Renaissance architecture and derivatives, a floor with formal reception and dining rooms; the principal story in a house, usually one flight above the ground.

piazza 1. A public open space or square surrounded by buildings. 2. A term occasionally used for a raised porch or veranda in French Vernacular architecture or in American Colonial architecture and derivatives (especially in the South); often supported by columns or posts.

piazza house A term occasionally used for a Charleston house.

pick A hand tool used for loosening and breaking up closely compacted soil and rock; consists of a steel head which usually is curved, with a point on one or both ends, mounted on a wooden handle.

pick and dip, Eastern method, New England method A method of laying brick whereby the bricklayer simultaneously picks up a brick with one hand and, with the other hand, enough mortar on a trowel to lay the brick.

pickax A pick or mattock.

pick dressing The first rough dressing of hard quarried stone by use of a heavy pick or wedge-shaped hammer.

picked finish In stone masonry, a surface finish covered with small pits produced by a pick or chisel point striking the face perpendicularly.

picket Same as pale, 1.

picket fence A fence formed of a series of vertical pales, posts, stakes, rods, etc. (sometimes sharpened at the upper end) which are joined together by horizontal rails.

picking, stugging, wasting Same as dabbing.

picking up The blending of a coat of freshly applied paint with another over which it is applied. Also see pulling up.

pickled Said of a metal surface which has been treated with a strong oxidizing agent, such as nitric acid, to clean, to provide a strong inert oxide film, and to increase corrosion resistance.

pick point A location on the ceiling of an auditorium from which a banner, microphone, scenic element, or the like may be supported and lowered as required.

pickup The unwanted adherence of solids in contact with the open surface of a sealant.

pickup load The abnormal rate of heat consumption that takes place when a heating system is first turned on; represents the heat dissipated in bringing the piping and radiators to their normal operating temperature.

picnostyle, pycnostyle See intercolumniation.

picowatt (pW) A unit of power equal to a millionth of one-millionth of a watt (i.e., 10^-12 W).

picture molding, picture rail Any of numerous types of moldings or other such devices formed so as to support picture hooks at or near the ceiling.

picture plane In perspective drawing, a plane upon which can be projected a system of lines or rays from an object to form an image or picture.

Picturesque Gothic A term sometimes applied to High Victorian Gothic architecture.

Picturesque Movement A movement established by a group of architects from about 1840 to 1900, particularly in Europe, wedded to the concept that architectural ideals should look away from formal Classical architecture and instead should embrace the romanticized past. The term “Picturesque” is not indicative of a particular architectural style, but is suggestive of a number of styles or modes of architecture that were related to the romanticized past, including: Exotic Revival, Gothic Revival, Italianate style, Queen Anne style, Richardsonian Romanesque style, Second Empire style, Stick style, Swiss Cottage architecture.

picture window In a home or apartment, a large, fixed window, often between two narrower operable windows; usually located so as to present the most attractive view of the exterior.

piece dyeing The dyeing of fabric after it has been woven, in contrast to dyeing the yarn prior to weaving.

pieced timber 1. A timber made from two or more pieces of wood fitted together. 2. A damaged timber repaired with a fitted piece of wood.

piece mark A mark placed on an individual piece of an assembly, designating its location in the assembly as indicated in shop drawings.

pièce sur pièce construction In the French Vernacular architecture of Louisiana, primarily in the 18th century, a method of building small houses of well-finished, heavy rectangular-hewn timbers. Each timber, laid horizontally, had a dovetail notch at both ends, forming a strong interlocking rigid joint with another appropriately notched timber at right angles to it.

pien, piend 1. The ridge of a roof. 2. An arris ; a salient angle.

pien check, piend check In a stair constructed with hanging steps of stone, a rabbet cut along the lower front edge of a step which fits into the back of the step next below it.

piend rafter Same as hip rafter.

pien joint In a stone stair, the joint between two steps which are secured by a pein check.

pier 1. A column designed to support concentrated load. 2. A member, usually in the form of a thickened section, which forms an integral part of a wall; usually placed at intervals along the wall to provide lateral support or to take concentrated vertical loads.

pier-and-spandrel Descriptive of a wall construction having the vertical metal columns which project beyond the plane of the windows and the spandrels.

pier arch An arch resting on piers, esp. one along a nave arcade.

pier block See double corner block.

pier bonding A method of bonding piers to walls by bond bricks or stones.

pier buttress A pier, 1 which receives the thrust of a flying buttress.

pierced louver, punched louver A louver that is formed in the face sheets or panels of a door.

pierced wall, perforated wall, screen wall A nonbearing masonry wall in which an ornamental pierced effect is achieved by alternating rectangular or shaped blocks with open spaces.

pierced work Ornamentation characterized by patterns formed by perforations; also see gingerbread and openwork.

pier glass A tall, narrow mirror, often running from floor to ceiling, which covers the whole or a large part of the wall between two windows.

pierrotage In French Vernacular architecture of the southern United States, lime mortar or clay mixed with small stones; used as infilling between half-timbering with diagonal braces (columbage); also see bousillage.

pietra dura A thin slab of inlaid stone used for ornamental purposes.

pieux à travers In the French Vernacular architecture of Louisiana, primarily in the 18th century, upright cypress stakes, driven into the ground in front of a house; similar in appearance to a picket fence.

piezometer A device for measuring liquid pressure; used to measure the pore water pressure in soil.

pigeonhole 1. One of a series of small compartments. 2. A seat in the top row of a gallery or in the uppermost gallery in a theater.

pigeonhole corner An acute angle formed in a brick wall, using square-ended bricks that have not been shaped.

pigeonholed wall Same as honeycomb wall.

pigeonnier, pigeon house Same as dovecote.

pigeon roof A roof having four steeply sloping sides that meet in a point, occasionally with a decorative element atop it; also called a pyramid roof.

pig iron Crude high-carbon iron ore that has been smelted and cast into ingots; may be remelted and used as a source of material for architectural cast-iron products, or may be further refined for use in producing steel.

pigment 1. A finely ground inorganic or organic powder which is dispersed in a liquid vehicle to make paint; may provide, in addition to color, many of the essential properties of a paint—opacity, hardness, durability, and corrosion resistance. 2. Coloring matter, usually in the form of an insoluble fine powder, used to color concrete, etc.

pigment figure A pattern in wood consisting of variations in color rather than variations in grain; found in such woods as rosewood and zebrawood.

pigment-to-binder ratio The ratio of the weight of pigment to the weight of binder in a paint, e.g., the number of pounds of pigment per 100 lb of binder.

pigment volume concentration See PVC, 1.

pigtail A flexible conductor which is attached to an electric component, providing a means of connecting the component to a circuit.

pigtail splice A type of connection made between two electric conductors; formed by placing the ends of the conductors side by side and then twisting the ends of the two conductors around one another.

pig tin A metal which is at least 99.80% pure tin.

pila 1. In churches in Italy, a holy-water font, consisting of a bowl mounted on a shaft, as distinguished from a font hanging from or secured to a wall or pier. 2. A square block or epistyle, just over the columns, to support a rooftimber. 3. A mortar which is valuable or curious on account of its antiquity or design.

pilaster 1. An engaged pier or pillar, often with capital and base. 2. Decorative features that imitate engaged piers but are not supporting structures, as a rectangular or semicircular member used as a simulated pillar in entrances and other door openings and fireplace mantels; often contains a base, shaft, and capital; may be constructed as a projection of the wall itself. (See illustration p. 726.)

pilaster base Same as base block.

pilaster block See double corner block.

pilaster buttress A pilaster that diminishes gradually in width with increasing height.

pilastered chimney A chimney shaft having pilasters on its faces to provide a decorative effect and/or to enhance its structural strength.

pilaster face The form for the front surface of a pilaster, parallel to the wall.

pilaster mass An engaged pier built up with the wall, usually without the capital and base of a pilaster.

pilaster side The form for the side surface of a pilaster, perpendicular to the wall.

pilaster strip, lesene Same as pilaster mass but usually applied to slender piers of slight projection; in medieval architecture and derivatives, often joining an arched corbel table.

pilastrade A row of pilasters.

pilastrelli A small pilaster flanking a window or door.

pile 1. A concrete, steel, or wood column, usually less than 2 ft (0.6 m) in diameter, which is driven or otherwise introduced into the soil, usually to carry a vertical load or to provide lateral support. 2. See carpet pile. 3. A term used to indicate the number of rooms in a house from front to rear; for example, a double-pile house has two rooms between the façade and the rear wall of the house.

pile bearing capacity The load on a pile, or the load per pile, on a group of piles, required to produce a condition of failure.

pile bent Piles which are driven in a row which is transverse to the long dimensions of a structure and which are fastened together by a pile cap and sometimes bracing.

pile butt The head of a pile.

pile cap 1. A slab or connecting beam which covers the heads of a group of piles, tying them together so that the structural load is distributed and they act as a single unit. 2. A metal cap which is placed, as temporary protection, over the head of a precast pile while it is being driven

pile core Same as mandrel, 1.

pile cushion A device placed between the drive cap and the top end of a concrete pile as protection against crushing and spalling.

pile driver A machine for delivering repeated blows to the top of a pile for driving it into the ground; consists of a frame which supports and guides a hammer weight, together with a mechanism for raising and dropping the hammer or for driving the hammer by air or steam. Also see sonic pile driver.

pile driving cap See drive cap.

pile eccentricity The deviation of a pile from its plan location, or the out-of-plumbness of a pile; reduces the vertical load capacity.

pile encasement A protective covering on a pile.

pile extractor A machine for pulling piles from the ground, e.g., by means of a double-acting pile hammer attached to a pile, each blow of which produces an upward force on the pile.

pile foot The lower end of a pile.

pile forte In sexpartite vaulting, the alternation between massive and slender piers.

pile foundation A system of piles, pile caps, and straps (if required) that transfers the structural load to the bearing stratum into which the piles are driven.

pile friction The sum of friction forces acting on an embedded pile; is limited by (a) the adhesion between the pile and the soil and/or (b) the shear strength of the soil adjacent to the pile.

pile hammer Equipment employing a weight (hammer) which strikes a pile or beam, forcing it into the ground; the weight may fall freely, under the action of gravity, or be powered by steam, compressed air, or a diesel engine.

pile head The upper end of a pile.

pile height See carpet pile height.

pile helmet Same as pile cap, 2.

pile hoop Same as drive band.

pile load test A test in which a load (usually 150% or 200% of the design load) is applied on a pile to verify or aid in the selection of a design load.

pile penetration The depth which is reached by the tip of a pile.

pile rig Same as pile driver.

pile ring Same as drive band.

pile shoe A pointed or rounded metal device on a pile foot to aid in pile driving.

pile tolerance 1. The permitted deviation of a pile from the vertical. 2. The permitted deviation in the horizontal plane.

pile tower Same as peel.

pile weight See carpet face weight.

pilier In French Vernacular architecture of Louisiana, a stack of rectangular blocks of (rotresistant) cypress wood used to support a Creole house, transferring the structural load from the groundsill to the earth below.

pilier cantonné High Gothic form of the compound pier, with a massive central core to which are attached at 90° intervals four colonettes supporting the arcade, the aisle vaultings, and the responds of the nave vaults.

piling The property of a paint which causes it to gain viscosity rapidly during application, making it difficult to apply a smooth uniform film.

piling pipe A seamless pipe or welded pipe, having beveled ends for welding or plain ends, where the cylinder section acts as a shell to form cast-in-place concrete piles or as a permanent load-carrying member.

pillar A column, pier, pilaster, or post that is capable of providing major vertical support.

pillar bolt A stud bolt which projects; used for supporting a part near its outer end.

pillar piscina A free-standing piscina resting on a pillar.

pillar-stone 1. Same as cornerstone. 2. A stone memorial, usually pillar-shaped.

pillow capital See cushion capital.

pillowed See pulvinated.

pillowwork The decorative treatment of any surface with pillow-like projections.

pilot boring In foundation construction, a preliminary boring or series of borings used to determine boring requirements.

pilot hole A hole which serves as a guide for a nail or screw, or for drilling a larger-size hole.

piloti (pl. pilotis) One of a number of isolated columns, posts, or piles that support a building, raising it above ground level; the ground floor is open to the exterior.

pilot lamp Same as pilot light, 1.

pilot light 1. A light which is associated with and indicative of the operation of a circuit, control, or device. 2. A small flame (which burns constantly) used to ignite the burner in a gas appliance.

pilot nail A temporary nail which is used to hold boards or timbers together until the permanent nails are driven in.

pilot punch A machine punch in which the cutting tool is provided with a small central plug which fits into a hole in the material and acts as a guide for punching a larger hole.

pilot valve An automatic valve that regulates the air pressure in a compressor.

pin 1. A peg or bolt of wood, metal, or any other material, which is used to fasten or hold something in place, fasten things together, or serve as a point of attachment or support. 2. A round bar of steel used to connect members of a truss.

pinacotheca A picture gallery.

pinaculum In ancient Greek or Roman architecture, a roof terminating in a ridge (the ordinary covering for a temple; in contrast, private houses had flat roofs).

pinax A decorative panel which fills the intercolumniations of the proskenion or the thyromata (pl. of thyroma) at the back of the stage of an ancient Greek or Roman theater.

pincers A tool having two hinged jaws which can be closed tightly; used for gripping objects.

pinch bar, claw bar, ripping bar, wrecking bar A steel bar with a U-shaped claw at one end and a chisel point at the other; often used as a lever for lifting heavy objects.

pin-connected truss Any truss having its main members joined by pins.

pin drill A drill for boring pin holes, 5 in truss members.

pine The wood of a number of species of coniferous evergreen distributed throughout the world; may be divided into two classes: soft (white) pine and hard (pitch) pine. An important source of construction lumber and plywood.

pineapple 1. An ovoid, imbricated finial. 2. A decorative molding.

pineapple ornament A decoration, usually carved in wood or cast in plaster, that resembles the cone of a pine tree; often found as a pendent or finial.

pine oil A strong, high-boiling-point solvent obtained from the resin of pine trees; used in paint to provide good flow properties in application.

pine shingles Shingles of pine wood; much used in Europe and, at one time, in the US

pine tar A viscous black substance, used in roofing, which is manufactured by distilling pine wood.

pin hinge A hinge having a pin on which the hinge pivots; also see loose-pin hinge.

pinhole 1. In wood, a round hole usually less than 1/4 in. (0.6 cm) in diameter, caused by the boring of a beetle or worm in standing timber. 2. In a plaster coat, a surface defect resulting from trapped air bubbles. 3. In a paint film, one of many small holes caused by: (a) impurities (in the paint, on the paintbrushes or rollers, or on the surface being painted); (b) solvent bubbling; or (c) moisture. 4. In the surface of a ceramic body, glaze, or porcelain enamel, an imperfection characterized by a depression resembling a pinprick. 5. A hole in a structural member through which a pin, 2 passes and connects with another member.

pin joint A joint in which one member is fastened to another by a pin so that rotational movement at the point of joining is not restricted.

pin knot 1. (US) A knot in wood that is no larger than 1/2 in. (1.27 cm) in diameter. 2. (Brit.) A knot in wood less than 1/2 in. (0.64 cm) in diameter.

pinnacle 1. An apex. 2. In Gothic architecture and derivatives, a small, largely ornamental body or shaft terminated by a pyramid or spire. 3. A turret, or part of a building elevated above the main building.

pinned joint A joint that is secured by the use of wood dowels rather than by wedges.

pinner In masonry construction, a small stone which supports a larger one.

pinnacle, 2: St. Mary’s, Oxford

pinning 1. Fastening or securing with a pin. 2. A foundation or underpinning.

pinning in The operation of filling in the joints of masonry with spalls or chips of stone.

pinning up The operation of driving in wedges in order to bring an upper work fully to bear on shoring or underpinning beneath.

pinrail See fly rail.

pin spotlight A small spotlight, focused in a relatively narrow beam, used to highlight an object of interest; for example, it may be mounted in the ceiling to illuminate a picture on a wall.

pintle A pin on which something is hung and about which it revolves; esp. one that projects upward.

pintle hinge A hinge that pivots about an upright pin or bolt.

pin tumbler A lock mechanism having a series of small cylindrical pins which form obstacles to rotation of the locking mechanism unless actuated by the proper key.

pipe A continuous tubular conduit, generally leakproof, for the transport of liquids and gases.

pipe batten A batten, 9 used to hang scenery from stage rigging in a theater.

pipe bend A pipe fitting, 1 used to achieve a change in direction.

pipe bracket Any of a variety of shaped metal assemblies used to support a pipe from a wall or floor.

pipe chase See chase.

pipe column A column made of steel pipe; may be filled with concrete.

pipe coupling A coupling.

pipe covering A wrapping around a pipe which acts as thermal insulation and/or a vapor barrier.

pipe cross A pipe fitting, 1 having four openings in the same place, at right angles to each other.

pipe cutter A hand tool for cutting pipe or tubing; one end of the tool, which partially encircles the pipe, carries one or more sharp wheels; the cutting edge of the wheels is forced against the pipe by a screw on the other end of the tool; cutting is effected by rotating the tool around the pipe.

pipe die Any of several types of adjustable tools for cutting threads on pipes used in plumbing.

pipe duct A duct in which only pipes are run.

pipe elbow See elbow, 1.

pipe exfiltration See exfiltration, 2.

pipe expansion joint A device, other than a fabricated U-bend, which expands or contracts to compensate for pipe contraction or expansion.

pipe fitting See fitting, 1.

pipe gasket A gasket, 2 in a piping system.

pipe hanger A device to support a pipe or group of pipes from a slab, beam, ceiling, or other structural element.

pipe heating cable See strip heater.

pipe hook A device for supporting a pipe from a wall.

pipe infiltration See infiltration.

pipe insulation Thermal insulation (such as fiberglass or foamed plastic) usually manufactured in hemicylindrical shapes for pipes of various diameters.

45 ° pipe lateral A pipe fitting similar to a pipe tee except that the side opening is at a 45° angle.

pipelayer An attachment for a tractor or other prime mover that consists of a winch and a side boom for lowering sections of pipe into a trench.

pipeline heater A heater for a pipeline, usually wrapped around the piping and heated by an electric current; used to prevent the liquid in the piping from freezing or, changing its viscosity.

pipeline refrigeration Refrigeration provided by piping a refrigerant to a group of buildings from a central refrigerating plant.

pipe pile 1. A pipe section heavy enough to be driven without a mandrel, 1 having its lower end either open or closed; after the pipe is driven to its final position, it is filled with concrete. 2. A pipe (either close-ended or open-ended) which serves as a pile.

pipe plug A threaded pipe fitting with male threads; used to close the end of a ferrule or a pipe having female threads.

pipe reducer For a pipe, see reducer.

pipe ring Any of a variety of circularly shaped metal assemblies used to support a pipe loosely from a suspended rod.

pipe run The path taken by piping.

pipe saddle A vertical support on which a pipe rests.

pipe schedule (sprinkler) system A fire sprinkler system in which the sizing of the pipes supplying the sprinklers is determined from a schedule based on occupancy classification; a specified number of sprinkler (heads) may be supplied for a specific size of pipe.

pipe sleeve 1. A cylindrical insert, placed in a form for a concrete wall, in a location where a pipe is to pierce the wall; the insert prevents concrete from flowing into the cylindrical opening. 2. A pipe coupling.

pipe stock A device to hold a pipe die.

pipe stop A spigot in a pipe.

pipe strap A thin metal strip used to hang pipe.

pipe support A mount for supporting a large pipe; often on a saddle, 3. A support of this type may include a roller to permit movement of the pipe caused by its expansion and contraction.

pipe tee A T-shaped pipe fitting with two outlets, one at 90° to the connection to the main line.

pipe thread A V-cut screw thread, cut on the inside or the outside of a pipe (or on a pipe fitting, coupling, or connector); the diameter of the thread is not constant, but tapers.

pipe tongs A tool used by plumbers or pipe fitters to screw or unscrew lengths of pipe or pipe fittings.

pipe trim The exposed metal appurtenances of plumbing fixtures, such as faucets, spigots, and exposed traps.

pipe underlayment The base on which a pipe is laid in the ground in order to achieve a firm, even bearing.

pipe vise A vise for holding pipe or tubing during cutting or threading operations; the pipe is held either in V-shaped serrated jaws or (for larger pipe) by chains.

pipe wrench A hand tool having one jaw movable and the other relatively fixed, the two being shaped so as to tighten when placed on a pipe and rotated in one direction.

piping 1. The movement of soil particles by water which percolates through the soil, leading to the development of erosion channels. 2. A run of pipe.

piping loss The loss of heat from piping between the source of heat and radiators.

pirca A type of crude wall construction using dry-laid unshaped stones, found in the Andes.

pisay Same as pisé.

piscina A shallow basin or sink, supplied with a drain pipe, generally recessed in a niche. (See illustration p. 732.)

pisé 1. Same as rammed earth. 2. A mixture of clay and chopped straw, sometimes with the addition of gravel; particularly used in wall construction. 3. Cob used as a wall material.

pishtaq In Muslim or Persian architecture, a monumental gateway marking the entrance to a mosque, caravanserai, madrasah, or mausoleum.

pit 1. An orchestra pit. 2. A small circular hole in a paint film; also see pockmarking. 3. An excavation; a hole in the ground.

pit boards Horizontal boards used as sheeting to retain earth around a pit.

pitch 1. The slope of a roof, usually expressed as a ratio of vertical rise to horizontal run, or in inches (centimeters) of rise per foot (meter) of run. 2. See grade. 3. The slope of a stair flight, i.e., the ratio of the rise to the run of the flight. 4. The distance between centers of bolts, rivets, and other fasteners in the same line. 5. See carpet pitch. 6. In acoustics, that attribute of auditory sensation in which sounds may be ordered on a scale from low to high; depends primarily on the frequency of the sound stimulus. 7. Any of various resins. 8. A dark, viscous, distillate of tar; used in caulking and paving; also called pitch mastic. Also see coal tar pitch. 9. In masonry, to square a stone with a chisel.

pitch board, gauge boar d A template, usually a right triangle in shape; used as a pattern to lay out the outline of stairs or the like; in stair construction, the base of the triangle is the exact width of the treads of the steps, and the perpendicular is the height of the riser.

pitch dimension Of stairs, the distance between the bases of the top and bottom risers in a flight, measured parallel to the slope.

pitched roof 1. A steep gable roof having the same pitch on each side of a central ridge. 2. Occasionally, a synonym for a gable roof.

pitched-roof dormer A dormer having a triangularly shaped gable.

pitched skylight A skylight whose members are inclined.

pitched stone A rough-faced stone having each edge of the exposed face pitched at a slight bevel, nearly in the plane of the face.

pitcher house A wine cellar.

pitch-faced In masonry, having all arrises cut true and in the same plane, but with the face beyond the arris edges left comparatively rough, being simply dressed with a pitching chisel.

pitch fiber pipe Same as bituminized fiber pipe.

pitchhole A recess or depression occurring in the surface of a stone which has otherwise been more or less dressed to a true face for setting.

pitching chisel, pitching tool A mason’s chisel having a wide, thick edge; used in rough dressing.

pitching piece See apron piece.

pitching tool See pitching chisel.

pitch knot A knot associated with a local area of pitch or resin; usually found in softwoods.

pitch mastic See pitch, 8.

pitch pine Same as yellow pine.

pitch pocket 1. A defect in softwoods; consists of an opening in the grain that contains pitch or resin. Also called a resin pocket. 2. A metal flange around the base of any roof-penetrating member (or component) which is filled with pitch or flashing cement to provide a seal.

pitch streak, resin streak A local accumulation or streak of highly resinous wood in softwoods.

pith The soft central core of a log.

pith fleck A short dark streak in wood resembling pith, but caused by insect attack during growth.

pith knot A knot with a small pith hole in the center.

pith ray See medullary ray.

pitot tube A device, used in conjunction with a suitable manometer or other pressure-reading instrument, for measuring the velocity of air in a duct or water in a pipe.

pit-run gravel, bank-run gravel Ungraded gravel as it is taken directly from a gravel pit.

pit sawing An old method of handsawing timber lengthwise; the log is supported over a pit to provide easy access by men using a double-ended saw.

pitting 1. The development of small cavities in a surface, owing to phenomena such as corrosion, cavitation, or (as in concrete) localized disintegration. 2. In plastering, see popping. 3. The development of localized surface defects on a metal surface, e.g., small depressions, usually caused by electrochemical corrosion. 4. The localized corrosion in the form of cavities which takes place on the surface of a metal.

pivot 1. A hinge. 2. The axle or pin about which a window or door rotates.

pivoted door A door hung on pivots (either center pivots or offset), as distinguished from one hung on hinges or on a sliding mechanism.

pivoted window A window having a sash (ventilator) which rotates about fixed vertical or horizontal pivots, located at or toward the center, in contrast to one hung on hinges along an edge. Also see vertically pivoted window.

pivot window A window that turns about hinges usually aligned along a vertical axis.

pixis, pix A shrine to contain the host or consecrated wafer. (See illustration p. 734.)

PL 1. On drawings, abbr. for pile. 2. On drawings, abbr. for plate. 3. On drawings, abbr. for plug. 4. On drawings, abbr. for “power line.” 5. Abbr. for “pipe line.”

placage An ornamental thin masonry facing (revetment) of a building.

placard Same as pargeting.

placeability See workability, 1.

place brick A poor quality brick that lacks weather resistance; same as salmon brick.

placement The placing and consolidation, 1 of concrete.

place of assembly 1. A building (excluding dwelling units), or portion thereof, in which a specified number (the actual number depends on the local code) of persons may gather for recreational, educational, political, social, or other purposes, such as to await transportation, or to eat or drink. 2. An outdoor space where a number of persons in excess of a specified minimum may gather for any of the above purposes.

placing 1. The deposition and compaction of freshly mixed mortar or concrete in the place where it is to harden. 2. The process of applying plastic terrazzo mix to the prepared surface.

placita A central enclosed courtyard in Spanish Colonial ranches in the Americas, surrounded by a high adobe wall; usually entered through a massive gate.

plafond A ceiling, esp. one of decorative character; flat or arched.

plain ashlar Stone facing that has been smoothed with a tool.

plain bar A reinforcing bar without surface deformations, or one having deformations that do not conform to the applicable requirements.

plain concrete, unreinforced concrete 1. Concrete without reinforcement or reinforced only for shrinkage or temperature changes. 2. Concrete without some other specific admixture or element, in contrast with concrete containing such an admixture or element, e.g., non-air-entrained concrete.

plain-cut joint In masonry, same as rough-cut joint.

plain lap Same as lap joint, 2.

plain masonry Masonry without reinforcement, or reinforced only for shrinkage or temperature change.

plain rail In a double-hung window, a meeting rail having the same thickness as other members of the frame of the sash.

plain reinforcement In reinforced concrete, any reinforcement, 1 other than deformed reinforcement.

plain-sawn, bastard-sawn, flat-grained, flat-sawn, slash-sawn Descriptive of wood sawn so that the annual rings intersect the wide face at an angle of less than 45°.

plain slicing Same as wood veneer, 1 that is sliced from a log without regard to the direction of the grain.

Plains cottage, Plains house Typically, a relatively simple single-family, single-story house, constructed primarily of sod, having two to five rooms; primarily built in the 19th century in those parts of the Great Plains where sod was usually the only construction material conveniently obtainable; also see sod house and straw bale house.

plain tile A flat rectangular roofing tile of concrete or burnt clay; each tile has two projecting nibs for hanging the tile from battens.

plaisance Same as pleasance.

plan 1. A two-dimensional graphic representation of the design, horizontal dimensions of a building, and location, as seen in a horizontal plane viewed from above, in contrast to a graphical representation representing a vertical plane (such as a section, 2 or an elevation, 1). See center-hall plan, city plan, cruciform plan, community plan, floor plan, four-square plan, gable-front-and-wing plan, gable-front plan, Georgian plan, ground plan, hall-and-parlor plan, hall-house plan, H-plan, linear plan, L-plan, one-room plan, open plan, Penn plan, Quaker plan, reflected ceiling plan, side-hall plan, single-room plan, three-room plan, T-plan, two-room plan, U-plan. 2. When used in the plural, a set of drawings, including elevations and sections, that collectively define a building. 3. See city plan and town plan.

planar frame A structural frame composed of individual members all of which are in the same plane.

planch (Brit.) 1. A floorboard. 2. A plank floor.

planching Same as flooring.

plancier, planceer, plancer, plancher 1. The soffit or underside of any projecting member, as a cornice. 2. A planch.

plancier piece A board which forms a plancier.

plan deposit See deposit for bidding documents.

plane 1. A tool for smoothing wood surfaces; consists of a smooth soleplate, from the underside of which projects slightly the cutting edge of an inclined blade; there is an aperture in front of the blade for the shavings to escape. 2. A surface, any section through which by a like surface is a straight line. 3. Of a column, the surface of a longitudinal section through the axis of the column.

plane ashlar A stone block having tool marks on its surfaces.

planed lumber Same as dressed lumber.

planed matchboards See dressed and matched boards.

plane of weakness Of a structure under stress, that plane along which fracture is most likely to take place, as a result of design or accident or the properties of the structure and its loading.

plane surveying A branch of the art of surveying in which the surface of the earth is considered a plane surface; curvature of the earth is neglected, and computations are made using the formulas of plane geometry and plane trigonometry.

plane table In surveying, a device for plotting the lines of a survey directly from the observations; consists essentially of a drawing board on a tripod, with a ruler, the ruler being pointed at the observed object by the use of a telescope or other sighting device.

plane tile See ridge tile.

planimeter A mechanical integrator for measuring the area of a plane surface usually within a given perimeter on a map.

planing A process for smoothing the surface of a material by shaving off small fragments.

planing machine 1. A stationary machine for planing wood. 2. A portable machine for planing the surface of a wood floor.

planing skip See skip.

planish finish A bright smooth finish on a metal; usually obtained by beating the metal with a special hammer or by passing it through rollers.

plank A long, wide, square-sawn thick piece of timber; the specifications vary, but often the minimum width is 8 in. (20 cm), and the minimum thickness is 2 to 4 in. (5 to 10 cm) for softwood and 1 in. (2.5 cm) for hardwood.

plank fence Same as board fence.

plank frame 1. Any framework consisting only of nailed planks. 2. A frame construction consisting of girts, plates, posts, and sills as bearing members and heavy planks as nonbearing partitions and walls.

plank-frame house A type of 17th-century colonial house constructed of heavy wood planks, usually erected vertically by setting them into grooves in a sill plate, 1 for support; they were then drilled and pegged at their lower ends, or otherwise held firmly in place.

plank house A large house, generally rectangular, constructed of planks ; used and built by Indians and, less frequently, by Eskimos.

planking 1. A flooring surface or covering made of planks. 2. The laying of planks. 3. See decking. 4. In log cabin construction, a term occasionally applied to logs that have been hewn only on two opposite sides.

planking and strutting Temporary timbers at the side of an excavation.

plank-in-the-ground construction See plaunch debout en terre construction.

plank-on-edge floor, solid-wood floor A floor formed by joists in contact with one another (rather than spaced apart), their upper edges forming a continuous surface upon which finish flooring is applied.

plank truss A roof truss constructed of planks.

plank-type grating An aluminum extrusion used primarily as a structural flooring member and consisting of a tread plate reinforced by integral I-beam ribs, with perforations in the tread plate between the ribs.

planned development A residential or commercial area which is developed, maintained, and operated as a single entity.

planned maintenance The maintenance of a building, and/or its contents, on a schedule that is determined by the results of past experience and performance. Also called scheduled maintenance. Compare with corrective maintenance, periodic maintenance, and preventative maintenance.

planning 1. The process of studying the layout of spaces within buildings and of buildings and other facilities or installations in open spaces in order to develop the general scheme of a building or group of buildings. 2. See community planning.

planning grid An arrangement of one or more sets of regularly spaced parallel lines, with the sets at right angles or other selected angles to each other, and used like graph paper by architects and engineers to assist with modular planning.

plano-convex A shape of sun-dried brick, flat on one side, convex on the other, typical of early Mesopotamian construction.

plantation house The principal house of a plantation in the antebellum American South, typically having many of the following characteristics: two stories; a projecting two-story portico with Classic columns and a recessed central bay; thick brick walls at ground level (often stuccoed); in areas having a high water table, a raised basement, which often served as the location for service facilities, pantries, a wine cellar, servants’ rooms, and sometimes for a dining room; a spacious veranda extending along the façade at the second-story level where the air circulation was much better than at ground level, and often along the sides and the back as well; many tall French windows for cross-ventilation.

plant containerization The encasement of a growing plant, together with its root system, in a container.

planted In joinery and plastering, fabricated or made on a separate piece of stuff ; afterward fixed in place, as a planted molding.

planted molding, applied molding A molding which is nailed, laid on, or otherwise fastened to the work rather than cut into the solid material.

planted stop, loose stop A fillet or molding which is nailed to a doorframe, window frame, or lining, against which a door or casement is stopped; a stop, 1.

planter A permanent, ornamental container to receive planted pots or boxes, often nonmovable and integral with the finish of a building.

planting In masonry, laying the first courses of a foundation on a level bed.

planting box A box, usually wooden, designed to hold growing plants and to fit inside a permanent receptacle.

plant mix 1. Any mixture produced at a mixing plant. 2. A mixture, produced in an asphalt mixing plant, consisting of a mineral aggregate uniformly coated with asphalt cement or liquid asphalt.

plant room Same as mechanical room.

plasma arc cutting The cutting of metal by use of an electric arc that concentrates a jet of hot, ionized gas within a highly localized area.

plaster screed Same as screed, 3.

plaster stop A strip of metal placed along the corner of a wall before plastering; serves as a guide for plastering and as a reinforcement at the corner.

plasticizer An admixture used with concrete or mortar mix to make it workable with relatively little water.

plate rail, plaque rail A narrow shelf or rail along the upper part of a wall of a room; usually grooved to support plates that are on display.

platform floor A raised floor, usually designed to provide convenient access to cables beneath the floor.

platform lift A special type of elevator that raises or lowers a person over a small vertical distance; especially used where required by the Americans with Disabilities Act or where a ramp

or conventional elevator would be impractical.

plating A thin coating of one metal on another.

plaque A tablet that is affixed to the surface of a wall or set into a wall; often inscribed to commemorate a special event or to serve as a memorial.

plaque rail See plate rail.

plaster Usually a mixture of gypsum or lime with sand and water, producing a paste-like material that is applied in the plastic state, usually over lath fastened to a surface such as a wall or ceiling, or sometimes directly onto brick; it forms a hard surface when the water it contains evaporates. In some remote early settlements, when lime or gypsum was not available, a so-called plaster of fine white clay mixed with chopped straw was sometimes troweled onto a surface to produce a smooth finish on a wall or ceiling. Cow hair, cow dung, and/or chopped straw often was added to the plaster mixture to increase its mechanical strength when it dried. Gypsum later supplanted lime as the plaster of choice because of its superior properties. Also see mud plaster, ornamental plaster, plaster of paris, and stucco.