I

icehouse A building for storing ice that is usually cut during the winter from frozen lakes, rivers, or ponds for use later in the year; often located in a shady area; usually has overhanging eaves and thick exterior walls that are packed with thermal insulation and painted white to reduce the absorption of heat radiated from the sun.

ichnography The tracing of ground plans; the representation of a ground plot.

ICI Abbr. for “International Commission on Illumination.”

iconostasis A screen in a Greek Orthodox church, on which icons are placed, separating the chancel from the space open to the laity.

ID On drawings, abbr. for “inside diameter.”

IDSA Abbr. for “Industrial Designers Society of America.”

IEE Abbr. for “Institution of Electrical Engineers,” London.

IEEE Abbr. for “Institute of Electrical and Electronics Engineers.”

IERI Abbr. for “Illuminating Engineering Research Institute.”

IES 1. Abbr. for the “Illuminating Engineering Society of North America.” 2. Abbr. for (British) “Illuminating Engineering Society.”

IF Abbr. for “inside face.”

igloo, iglu A hemispherical shell, built by Eskimos of blocks of ice or packed snow as a temporary dwelling for a single family; usually about 10 to 15 feet (3 to 4.5 m) in diameter at its base, with the floor often partially below the surrounding terrain. Daylight within was provided by one or more blocks of relatively transparent freshwater ice, or by an opening covered with a piece of translucent seal intestine. Entry was usually along a domed passageway.

igneous rock A class of rock formed by change of the molten material to the solid state; generally termed granite if coarse-grained.

ignitability The ease with which ignition of a material can be initiated.

ignition The initiation of combustion, as evidenced by flame, glow, or explosion.

ignition source A heat source having sufficient energy to initiate combustion of a material.

ignition temperature Of a material, the minimum temperature required to initiate combustion.

I-house A side-gabled house, usually one-and-a-half or two stories high, one room deep, and two rooms wide; the two rooms usually have an entrance hall between them containing a central stairway.

IHVE Abbr. for “Institution of Heating and Ventilating Engineers.”

IIC Abbr. for impact isolation class.

I-joist A structural steel member having a cross section that resembles the capital letter I.

ILI Abbr. for “Indiana Limestone Institute.”

illite A clay mineral, a hydrous silicate of potassium, aluminum, iron, and magnesium; swells considerably on wetting and shrinks proportionately on drying.

illuminance The density of luminous power, also called “illumination.” One lumen of luminous flux, uniformly incident on 1 square foot of area, produces an illuminance of 1 footcandle; in SI units, one lumen of luminous flux, uniformly incident on 1 square meter of area, produces an illuminance of 1 lux.

illuminated sign A sign designed or arranged to emit or reflect light from an attached artificial source.

illumination The luminous flux density incident on a surface, i.e., the luminous flux per unit area; usually expressed in lumens per square foot or footcandles, and lumens per square meter or lux.

illumination level The quantity of light that illuminates a surface; measured in foot candles or in lux.

illumination meter, Brit. illumination photometer An instrument for measuring the illumination on a surface; usually consists of barrier-layer cells connected to a meter calibrated directly in a set of illumination units.

illumination photometer (Brit.) See illumination meter.

ILLUS On drawings, abbr. for “illustrate.”

ilmenite A mineral which is commonly used as an aggregate in high-density concrete; also called iron titanate.

image Any representation of form or features, but esp. one of the entire figure of a person; a statue, effigy, bust, relief, intaglio, etc.

imaret A type of hostelry for the accommodation of Muslim pilgrims and other travelers in the Turkish empire.

imbow Same as embow.

imbrex 1. A tile, semicircular in shape, which fits over the joints in a tile roof. 2. One of the scales in ornamental imbrication.

imbricate To overlap in regular order, as shingling, tiles, etc.

imbrication Overlapping rows of shaped tiles or shingles that resemble overlapping fish scales; also see contre-imbrication.

IMC Abbr. for intermediate metallic conduit.

IMechE Abbr. for “Institution of Mechanical Engineers.”

immersion heater A heater in which the electric heating element, submerged in a water tank, is controlled by a thermostat built into the tank or in contact with the water.

immersion vibrator A vibrator which is inserted in the fresh concrete during the agitation, 1 process.

impact factor In structural design, that factor by which a static load effect must be multiplied in order to find the increment of the dynamic effect of applying the load other than statically.

impact insulation, impact isolation 1. The use of structures and materials designed to reduce the transmission of impact noise in a building. 2. The degree by which transmission of impact noise is reduced by use of materials and structures for that purpose.

impact insulation class (IIC) A single-number rating used to compare and evaluate the performance of floor-ceiling constructions in isolating impact noises.

impact load The dynamic effect on a structure, either moving or at rest, of a forcible momentary contact of another moving body.

impact noise Sound generated by impact and carried through a structure; typically, footsteps, the slamming of a door.

impact noise rating (INR) A rating, expressed by a single number, which is a rough measure of the effectiveness of a floor construction in providing isolation against the noise of impacts; in general, the higher the number, the greater the effectiveness.

impact resistance The resistance of surface (or a material or product) to a shock, such as a hard blow.

impact strength, impact energy The amount of energy required to fracture a material; a measure of the material’s resistance to mechanical shock.

impact test A method of determining the resistance of a specimen to fracture upon the application of a dynamic physical shock.

impact wrench A wrench, driven pneumatically or electrically, which produces a series of impulsive torques.

impages 1. The broad transverse band on a door, which stretches from stile to stile and divides the panels horizontally from one another; a door rail. 2. The border or framework of a panel of a door.

impasto In painting, the thick laying of pigments.

impedance In alternating-current electric circuits, a quantitative measure of the opposition to the flow of current upon the application of voltage; measured in ohms.

impeller The rotating member in a pump consisting of a disk with vanes attached to it; moves liquid by accelerating the liquid radially outward.

impending slough The consistency of shotcrete which contains the maximum amount of water that can be used without flow or sag after placement.

imperfect arch A diminished arch.

imperial staircase See double-return stair.

impermeable Said of a soil whose particles are so closely spaced that the passage of water is either prevented or very slow.

impervious In ceramics, that degree of vitrification evidenced visually by complete resistance to dye penetration; generally signifies zero absorption of water, except for floor and wall tile, which may absorb up to 0.5% water.

impervious cover A ground surface that resists the infiltration of water, thereby resulting in a high rate of water runoff.

impervious soil A fine-grained soil, such as clay, having pores too small to permit water to pass except by slow capillary creep.

impetus The span of a building, roof, or arch.

IMPG On drawings, abbr. for “impregnate.”

implied indemnification An indemnification which is implied by law rather than arising out of a contract.

impluvium In ancient Roman dwellings, a cistern set in the atrium or peristyle to receive water from the roofs.

imposed load All loads, exclusive of dead load, that a structure is to sustain.

impost 1. A masonry unit or course, often distinctively profiled, which receives and distributes the thrust at each end of an arch. Also see abutment, springer. 2. A vertical member in a gemel or double window taking the place of a mullion; an integral mullion.

impost block, dosseret, supercapital A transitional member, often tapered, placed above a column capital to receive the thrust of vaults or arches.

impregnated cloth A cloth impregnated with resin, varnish, shellac, etc.

impregnated timber Timber into which a flame retarder, insect poison, and/or fungicide has been forced under pressure.

impregnation The process of adding chemical preservatives, resin, or fire retardants to wood under pressure. Also see Bethell process.

improved land Land which has been provided with water, sewers, sidewalks, and other basic facilities for residential or industrial development.

improved wood Wood impregnated with resin and cured with heat and pressure to increase its strength, durability, and moisture resistance.

improvement A structure or public utility or any other installation or physical change made in a property to increase its value and utility or to improve its appearance.

in. Abbr. for “inch.”

inactive leaf, inactive door That leaf of a pair of doors which does not contain a lock, and to which the strike plate is fastened to receive the latch or bolt of the active leaf; usually it is fixed in a closed position by bolts at the top and bottom of the door.

in-and-out bond In masonry, a bond, 6 formed by headers and stretchers alternating vertically, esp. when formed at a corner, as by quoins.

in antis See anta and distyle in antis.

in-bank measure Measurement of the volume of ground before it has been excavated.

inbark See bark pocket.

inbond In masonry, bonded or forming a bond across the thickness of a wall; composed largely or entirely of headers or bond-stones.

INC 1. On drawings, abbr. for “incorporated.” 2. On drawings, abbr. for “incoming.”

Inca architecture The architecture of the Inca Empire in Peru from the 12th cent. until the Spanish conquest in the 16th cent., particularly fortified towns with massive stonework.

incand Abbr. for “incandescent.”

incandescence The emission of visible light as a result of heating.

incandescent daylight lamp An incandescent lamp having a blue-green glass bulb which makes the emitted light whiter by absorbing part of the yellow and red light; approximately 35% less efficient than the standard incandescent lamp.

incandescent direct-light lamp, bird’s-eye lamp An incandescent lamp, usually with a PS- or A-shaped bulb which is silvered from the maximum diameter to the base, leaving a clear or frosted hemispherical region opposite the base end.

incandescent lamp, incandescent filament lamp A lamp from which light is emitted when a tungsten filament is heated to incandescence by an electric current.

incandescent lamp base See lamp base.

incandescent lamp filament See filament.

incandescent lighting fixture A luminaire, usually complete with incandescent lamp(s), socket(s), reflector, and often with a louver or diffusing medium.

incandescent special-service lamp One of a class of lamps with special properties to meet particular needs, such as vibration service lamps, rough service lamps, cold service lamps, etc.

incasement Same as encasement.

in cavetto The reverse of relief, differing from intaglio in that the design is impressed into plaster or clay.

incavo The hollowed or incised part of an intaglio.

incense cedar A close-grained wood having a fragrant resinous odor; highly resistant to moisture.

incertum opus See opus incertum.

inches of mercury A unit used as a measure of pressure; equal to the pressure exerted by a column of mercury 1 inch (2.54 cm) high; equivalent to a pressure of 3386.4 newtons per square meter.

inch of water A unit of pressure equal to the pressure exerted by a column of liquid water 1 in. high at a temperature of 39.2°F (4°C).

inch stuff Building materials having a nominal 1-in. (2.5-cm) thickness, although actually measuring less.

INCIN On drawings, abbr. for incinerator.

incinerator An apparatus in which solid, semisolid, or gaseous combustible wastes are ignited and burned.

incipient decay Early stages of decay in wood in which the color has changed but the strength and hardness have not yet been affected.

incise 1. To decorate by cutting or indenting a surface, as ceramic ware. 2. To perforate the surface of timbers, poles, posts, etc., to increase penetration of wood preservatives.

INCL On drawings, abbr. for “include.”

inclination The angle which a line or surface makes with the vertical, horizontal, or with another line or surface.

incline A sloping surface, i.e., neither horizontal nor vertical; a slope.

inclined-axis mixer, high-discharge mixer A truck equipped with a body for mixing concrete; consists of a revolving drum which rotates about an axis inclined to the bed of the truck chassis.

inclined end post An inclined compression member at the end of a truss.

inclined lift A powered passenger elevator, installed on a stairway; used to raise or lower a person from one floor to another.

inclined shore A raking shore.

inclinometer A device for measuring the horizontal movement within a soil mass.

inclusion The presence of foreign matter in a finished material.

incombustible Same as noncombustible.

increaser In plumbing, a tapered coupling for joining a pipe or conduit to another of larger size.

incrustation 1. The deposition of materials on the interior of pipes, vessels, or equipment from chemicals in the conveyed liquid. 2. A decorative skin or coating of rich materials applied over commoner construction.

IND On drawings, abbr. for “industrial.”

indemnification A contractual obligation by which one person or organization agrees to secure another against loss or damage from specified liabilities.

indent 1. The gap left by the omission of stone, brick, or block units in a course of masonry; used for bonding future masonry. 2. In a wall of a church, a space hollowed out of stone to receive a brass effigy.

indented bar A type of deformed bar.

indented bolt A type of anchor bolt with surface indentations to increase its grip.

indented joint A joint used in joining timbers end to end; a notched fishplate is attached to one side of the joint to fit into 2 corresponding notches in the joined timbers; the entire assembly is fastened with bolts.

indented molding, indenting A molding with the edge toothed or indented in triangular tooth-like shapes.

indented wire A type of wire having surface indentations to improve its bond when used in concrete reinforcement or for pretensioning tendons.

independent-pole scaffold Same as double-pole scaffold.

index of key words Part Four of the uniform system for construction specifications, data filing, and cost accounting.

index of plasticity See plasticity index.

Indian architecture The architecture of the Indian subcontinent, originally a timber and mud-brick architecture of which nothing survives. Early Buddhist monuments, chaitya halls, stupa rails, and toranas clearly imitate wood construction, and timber buildings appear on relief representations. All surviving architecture is of stone, using exclusively a structural system of post and lintel, brackets, and corbels. The basically simple Indian architectural forms are generally obscured and overwhelmed by a rhythmical multiplication of pilasters, cornices, moldings, aediculae, roofs, and finials, and an exuberant and sensuous overgrowth of sculptural decoration.

Indian oak See teak.

Indian shutters In many American colonial houses, sliding panels placed along the inner walls whose purpose may have been to increase protection against Indian arrows.

indicator bolt A door bolt which indicates whether a water closet is vacant or occupied.

indicator button A device incorporated in the lock of a door of a hotel room to indicate whether or not the room is occupied.

indicator light, indicator lamp Same as pilot light, 1.

indicator valve A valve whose design includes some mechanism to show that the device is open or closed.

indigenous Said of a plant or tree which is native to the area in which it is grown.

indirect cost On a building project, those costs that are attributed to overhead, as opposed to any specific task or component; for example, the cost of supervisory personnel in the site office.

indirect drain pipe Same as indirect waste pipe.

indirect expense Overhead expense; expense indirectly incurred and not directly chargeable to a specific project or task.

indirect footlight A footlight unit with light sources placed so that the light rays strike the area to be illuminated from a reflecting surface rather than directly.

indirect heating See central heating.

indirect lighting Lighting from luminaires which distribute 90% to 100% of the emitted light upward so that illumination is provided primarily by reflected light rather than by direct light.

indirect luminaire A luminaire which emits 90% to 100% of its total output above a horizontal plane through it.

indirect solar water heating system A solar water heating system employing a closed circulation loop through a heat exchanger; the fluid which flows through the solar collector is isolated from contact with other fluids in the system.

indirect system A heating, air-conditioning, or refrigeration system in which a fluid is circulated to the space or material to be heated or cooled, or is used to heat or cool air which is so circulated; the fluid (such as air, water, or brine) is heated or cooled by products of combustion, by electric heating, or by a refrigerant.

indirect waste pipe A waste pipe which does not connect directly with the building-drainage system, but discharges into it through a properly trapped fixture or receptacle.

indirect water heater A water heater in which the temperature of the water in the system is increased by means of a remotely-located heat exchanger.

individual sewage-disposal system A system of sewage treatment tanks and disposal facilities, designed for a single building, establishment, or lot, not served by a public sewer.

individual vent Of a plumbing fixture, a pipe which vents a fixture drain and which is connected to the main vent above it.

individual water supply A supply other than an approved public water supply which serves one or more families.

indoor air quality The quality of air inside a building; deemed to be acceptable by ASHRAE if it contains no contaminants at harmful concentrations, and if at least 80% or more of the people in the building who breathe this air do not express dissatisfaction with it.

induced draft The forced movement of air or gases caused by the suction created by the inlet side of a fan.

induced-draft boiler A boiler system having a power-operated fan at its discharge end; the fan draws air through the burner and boiler, conveying the products of combustion to the atmosphere through a short chimney.

induced-draft water-cooling tower A water-cooling tower having one or more fans located in the saturated air stream leaving the tower.

induced siphonage Siphonage of water from a fixture trap (i.e., the drawing away of water that forms a trap seal); usually due to an improperly installed vent pipe. As a result, when another fixture on the same vent pipe discharges, siphonage may be induced.

induction 1. In air conditioning, the entrainment of air in a room by the flow of a stream of primary air from an air outlet. 2. The process by which current in one conductor induces an electric current in a nearby conductor.

induction brazing A brazing process in which the required heat is obtained from the resistance of the work to an induced electric current.

induction heating In piping, the heat treatment of completed welds by the heat generated by the use of induction coils around the piping.

induction motor An alternating-current motor having its primary winding, on one member (which is usually the stator), connected to the source of electric power; a secondary winding on the other member (usually the rotor) carries the induced current.

induction soldering A soldering process in which the required heat is obtained from the resistance of the work to an induced electric current.

induction welding A welding process in which coalescence is produced by the heat obtained from resistance of the work to an induced electric current, with or without the application of pressure.

industrial area Any area devoted predominantly to manufacturing.

industrialized building system A building system of mechanized production design in which the subsystems and components have been integrated into an overall process, utilizing factors of planning, design, programming, production, transportation, and on-site assembly techniques. Also see systems building.

industrial design The art of utilizing the resources of technology to create and improve products and systems which serve human beings, taking into account factors such as safety, economy, and efficiency in production, distribution, and use. Such design may be expressed partly in external features, but predominantly in integrative structural relationships, responding to the perennial human need for meaningful form.

industrial lift A nonportable, power-operated hoisting and lowering mechanism for raising or lowering material vertically, operating entirely within one story of a building.

industrial occupancy 1. Use of a building for the manufacture of products of any kind. 2. Use of a building for processing, assembling, mixing, packaging, finishing or decorating, repairing, and similar operations. Also see general industrial occupancy, high-hazard industrial occupancy, special-purpose industrial occupancy.

industrial park A planned industrial or technologically-based district of a city; usually intended for light manufacturing, industrial usage, research, or for warehousing; often located in open land near the city or in a renovated urban area.

industrial tubular door A door constructed from tubular steel with locked seams; the corners are welded and all joints are ground smooth; the door panels consist of one or two sheets securely fastened to stiles and rails.

industrial waste A waterborne waste resulting from an industrial process; differs in composition from domestic sewage wastes.

industry standard specification In the construction industry, a specification based on codes, technical reports and disclosures, or on test procedures and results that have been shown to be of proven use and general acceptance.

inelastic behavior Deformation of a material that does not disappear on removal of the force that produced it.

inert base A paint base which does not provide hiding, color, or drying properties. Its main function is to provide solids, usually at low cost.

inert filler In paints, same as inert base.

inertia block A concrete block which serves as a base for mechanical equipment such as fans or pumps; the block is mounted on a resilient support to reduce the transmission of vibration to the building structure.

inert pigment 1. A nonreactive pigment. 2. An extender pigment, used to provide solids and bulk.

infant school (Brit.) A form of primary school which gives instruction to 4- to 7-year-old children in preparation for grammar school.

infilling Material used to fill the spaces, within a frame, between structural members of a building; provides additional thermal insulation, fire resistance, and stiffness. Also see fill insulation.

infiltration 1. The seepage or flow of air into a room or space through cracks around windows, under doors, etc. 2. In a concrete sewer pipe laid in soil, the volume of groundwater that enters the pipeline system.

infiltration basin An open-surface storage area for water having no outlet other than an emergency spillway.

infirmary A place which provides uncomplicated medical and nursing care, usually for residents or members of an institution, such as a school.

inflammable Same as flammable.

inflatable gasket A gasket whose effectiveness depends on a seal provided by inflation with compressed air.

inflatable structure See pneumatic structure.

inflected arch Same as inverted arch.

inflection point Same as point of inflection.

inflow The volume of any type of water entering a sewer pipe from outside sources not included under infiltration.

INFO On drawings, abbr. for “information.”

information outlet In a telephone wiring system in a building, a connection device designed for a fixed location (usually on a wall) in which telephone wiring terminates; the outlet contains a female jack to receive a male plug that is inserted into it. Such outlets are used to connect a telephone, FAX, telephone answering machine, etc., to a telephone line.

infrared That region of the electromagnetic spectrum at wavelengths immediately above the visible spectrum; the heat in this region of the spectrum which is generated by a light source usually is undesirable (since it represents a loss in efficiency), but such heat is used in industrial applications for drying, baking a surface, etc.

infrared drying Drying by use of infrared lamps to decrease drying time.

infrared emittance See emittance.

infrared lamp An incandescent lamp having a higher percentage of the radiant power in the infrared region than a standard incandescent lamp; has longer average life owing to the lower filament temperature; may have a red glass bulb to reduce the radiated visible light.

infrasound Acoustic oscillations having a frequency below the low-frequency limit (approximately 16 Hz) of audible sound.

infrastructure The basic equipment of a building that is necessary for the building to serve its intended function.

in-glaze decoration A ceramic decoration applied on the surface of an unfired glaze and then matured with the glaze.

ingle A fireplace; a hearth.

inglenook A fireplace hearth in a corner of a room; often provided with seating; same as chimney corner.

ingot A mass of molten metal which has been poured into a mold to solidify; it differs from a casting in that it requires rolling or forging to become a finished or semifinished product.

ingot iron Same as mild steel, 1.

ingrown bark, inbark See bark pocket.

inhibiting pigment A pigment (such as lead and zinc chromate, zinc oxide, red lead, zinc metal, and barium metaborate) added to paint to inhibit or prevent rust and corrosion of metals or the formation of mildew.

inhibitor A substance added to paint to retard drying, skinning, mildew growth, etc. Also see corrosion inhibitor, inhibiting pigment, drying inhibitor.

initial backfill The material used in filling a trench from the top of the bedding to a specified height above a pipe which is laid in the trench.

initial drying shrinkage The difference between the initial length of a moist concrete specimen and the length of the specimen after it is first dried and has reached a stable length; usually expressed as a percentage of the initial moist length.

initial grade Same as natural grade.

initial prestress The prestressing stress (or force) applied to prestressed concrete at the time of stressing.

initial rate of absorption See absorption rate.

initial set 1. A degree of stiffening of a mixture of cement (or concrete or mortar) and water less than final set; generally stated as the time required for cement paste to stiffen sufficiently to resist the penetration of a weighted test-needle. 2. Of a mastic compound, adhesive, or coating, the stage in curing or drying when the surface has become sufficiently firm to be unmarked when touched with the finger.

initial setting time The time required for a freshly mixed cement paste, mortar, or concrete to achieve initial set.

initial shrinkage The drying shrinkage that takes place during the setting of a cement, concrete, paste, mortar or the like; caused by the evaporation of moisture.

initial stress Stress in a prestressed concrete member before any loss of stress occurs.

injection burner A gas burner that employs a gas jet to thrust air for combustion into the burner and mix it with the gas.

injection molding A molding procedure whereby a heat-softened plastic material is forced from a cylinder into a relatively cool cavity which gives the article the desired shape.

inlaid parquet Inlaid wood flooring, often arranged in simple geometric or decorative patterns.

inlay, intarsia, marquetry 1. A shaped piece of one material embedded in another as part of a surface ornamentation. 2. Such ornamentation as a whole. Also see encaustic tile.

in-line centrifugal fan A centrifugal fan which is specially designed to be connected to the ductwork in direct line with the discharge from the fan housing.

in-line pump A pump supported directly by the system piping (i.e., the piping carries the weight of the pump); usually mounted vertically to save floor space, with its weight centered over the piping.

inn 1. A place which provides eating and drinking, but no lodging, for the public; a tavern. 2. A hotel. 3. A student hostel or residence. 4. A hospice.

inner bailey A courtyard within the central defenses of a castle.

inner bead Same as inside stop.

inner casing See inside casing.

inner court 1. An open, unoccupied space surrounded on all sides by the exterior walls of a building or structure. 2. An open, unoccupied space surrounded by the exterior walls of a building and an interior lot line of the same premises.

inner hearth That part of a hearth contained within a fireplace; the back hearth.

inner sanctum A most sacred place.

inorganic material A material which is composed of minerals, or made from minerals; not animal or vegetable in origin.

inorganic silt See silt.

inosculating column Same as clustered column.

inpaint To renew damaged areas on paintings or painted surfaces by repainting.

INR Abbr. for impact noise rating.

inrush current See lamp inrush current.

INS On drawings, abbr. for “insulate.”

insanitary Injurious to health or contrary to sanitary principles.

inscription Lettering, often monumental, decorating architecture inside or out.

insect screen, window screen A very light woven-wire used to prevent insects from flying through open windows or doors.

insect wire screening A woven wire screening having a mesh small enough to provide protection against insects.

insert 1. A nonstructural repair to correct an appearance defect in laminated timber. 2. An inlay of wood veneer, a patch, or a plug used to fill holes in plywood. 3. See patch, 2.

insert card reader A device for providing access to a locked door. The cardholder must insert a card (usually having a magnetic strip) into the device to unlock the door.

inserted column A column which is partially inserted in a wall; an engaged column.

inserted grille A grille that is fabricated separately for mounting in a prepared opening in a door.

inserted tenon See false tenon.

inset dormer A dormer that is partially set below a sloping roof, unlike the usual dormer that projects entirely above the sloping roof.

inset porch Same as integral porch.

inside-angle tool A float used in shaping inside angles in plastering and masonry.

inside caliper A type of caliper which is especially designed for measuring the inside diameter of a cylinder or the distance between shapes.

inside casing, interior casing The inside trim around the interior of a door or window frame.

inside chimney Same as interior chimney.

inside corner molding A molding covering the joint at the internal angle of two intersecting surfaces, as the metal coves used with plastic laminates, etc.

inside-door lock, room-door lock A lock having a spring bolt (operated by a knob) and a dead bolt operated by a key.

inside finish See interior trim.

inside glazing External glazing which is installed from inside the building. Also see internal glazing.

inside lining See inside casing.

inside micrometer A micrometer especially designed for the accurate measurement of the inside diameter of a cylinder, such as a pipe.

inside stop, bead stop, inner bead, stop bead, window bead, window stop In a double-hung window, a strip of wood fixed to the casing, along the inner edge of the inner sash; restricts the motion of the sash to a vertical plane.

inside thread The thread on the inside of a pipe, fitting, or machine screw.

inside trim 1. Any trim on the interior of a building. 2. Trim around door or window openings; also called inside casing.

in situ In place, as in cast-in-place concrete.

in situ concrete See cast-in-place concrete.

insoluble residue That portion of an aggregate or cement which is not soluble in diluted hydrochloric acid.

inspection 1. Examination of work completed or in progress to determine its compliance with contract requirements. 2. Examination of the work by a public official, owner’s representative, or others. 3. The process of measuring or checking materials, workmanship, or methods for conformance with quality controls, specifications, and/or standards.

inspection chamber A shallow manhole.

inspection eye Same as cleanout, 1.

inspection fitting Same as cleanout, 1.

inspection junction Same as cleanout.

inspection list A list of items of work to be completed or corrected by the contractor.

inspector 1. See building inspector. 2. See owner’s inspector. 3. See resident engineer.

instability In a structure, the sudden loss of stiffness that limits its load-carrying capability, and in some cases results in the structure’s failure.

instal Abbr. for “install” or “installation.”

instantaneous-type water heater A heater in which there is an exceedingly rapid increase in water temperature as the water flows through tubes surrounding an electric heating coil; best suited for applications requiring a continuous flow of hot water. Must be used with care when the demand is low because accurate temperature control at low flow rates usually is poor.

instant lock A lock which is actuated automatically (by a spring) as the door is closed.

instant-start fluorescent lamp A fluorescent lamp designed to be started by high voltage without preheating of the electrodes; usually has single-pin base connections; a slim-line lamp.

InstCES Abbr. for “Institution of Civil Engineering Surveyors.”

Institute of Electrical and Electronic Engineers (IEEE) A professional organization of electrical engineers having its headquarters in Piscataway, NJ 08855.

Institution of Electrical Engineers (IEE) A professional organization of electrical, electronic, and systems engineers having its headquarters at Savoy Place, London WC2R OBL.

Institution of Structural Engineers A professional organization of structural engineers having its headquarters at 11 Upper Belgravia Street, London 5W1 8BH.

institutional occupancy The use of a building for the medical treatment or care of persons suffering from illness or infirmity; for the care of infants, convalescents, or aged persons; or for penal or corrective purposes.

instructions to bidders Instructions contained in the bidding requirements for preparing and submitting bids for a construction project. Also see notice to bidders.

instructions to tenderers Same as notice to bidders.

insul Abbr. for “insulate” or “insulation.”

insula 1. In Roman town planning, a block of buildings surrounded by streets. 2. A Roman apartment house occupying such a block.

insulated flange A coupling used in metal pipes to interrupt the electrical transmission path that would otherwise exist.

insulating board See board insulation.

insulating cement 1. A combination of hydraulic-setting cement (or other bonding ingredient) and a loose-fill insulation, mixed to a workable putty-like consistency; used in insulation applications to fill voids, joints, etc. 2. A mixture of dry granular, fibrous, flaky, or powdery materials that develops a plastic consistency when mixed with water, and when dried in place; forms a coherent covering that provides substantial resistance to heat transmission.

insulating concrete Concrete having low thermal conductivity; used as thermal insulation.

insulating fiberboard Fibrous insulating material (such as wood, cane, or other vegetable fibers) and binder, formed into a board. Manufactured units vary widely in thickness, linear dimensions, density, thermal resistance, and mechanical strength.

insulating form board Insulation board used as a permanent form for poured-in-place gypsum or lightweight-concrete roof decks.

insulating glass Two sheets of glass that are assembled and sealed around their edges as a single unit; the space between the glass sheets is dehydrated or filled with a gas. Such a unit is effective in reducing the transfer of heat through it.

insulating glass unit A panel of double glazing which is sealed around its periphery; provides increased resistance against the transmission of heat and sound.

insulating material See electrical insulation, thermal insulation.

insulating oil A type of oil used within the enclosure of a transformer, switch, or other electric device, for insulating and cooling purposes.

insulating plasterboard See foil-backed gypsum board.

insulating strip An expansion strip.

insulating varnish A varnish used as insulator on wire or electric circuits.

insulation See electrical insulation, sound insulation, thermal insulation.

insulation board See board insulation.

insulation lath Gypsum lath having an aluminum foil laminated to its back in order to provide a vapor barrier and reflective insulation against thermal losses.

insulation resistance The resistance to the flow of current through an insulating material resulting from an impressed direct voltage; usually expressed in ohms.

insulation test A test to determine the resistance of electrical insulation to the flow of direct current.

insulator See electrical insulator.

insurance See: builder’s risk insurance; completed operations insurance; comprehensive general liability insurance; contractor’s liability insurance; employer’s liability insurance; liability insurance; loss of use insurance; owner’s liability insurance; professional liability insurance; property damage insurance; property insurance; public liability insurance; special hazards insurance; steam boiler and machinery insurance; workmen’s compensation insurance.

INT 1. On drawings, abbr. for “intake.” 2. On drawings, abbr. for “interior.” 3. On drawings, abbr. for “internal.”

intaglio 1. Incised engraving, as opposed to carving in relief. 2. The work producing such an object.

intaglio rilevato See sunk relief.

intake An opening through which water or air (or any other fluid) enters a system, chamber, plenum, pipe, or machine. Also see outside-air intake.

intake belt course A projecting course of masonry at a level where the wall is reduced in thickness.

intake door A door that penetrates a wall enclosing a refuse chute and through which waste material is deposited directly into the chute.

intarsia Mosaic inlay, especially a form of wood inlay.

integral frame A type of doorframe; the trim, backbends, rabbets, and stops are all formed from one piece of metal for each jamb and for each head.

integral garage A garage that is part of the structure of a building.

integral lean-to In a colonial timber-framed house in America, a lean-to that was part of the original house construction, not a later addition or separate structure. This construction permitted the use of continuous rafters between the roof ridge and the eaves of the lean-to, thus providing a long, sloping roof of uniform pitch.

integral lock A type of mortise lock having its cylinder in the knob.

integral mullion See impost, 2.

integral porch A porch whose floor is set within the main structure of a house, rather than being attached to the house, as in a projecting porch.

integral waterproofing The so-called “waterproofing” of concrete by the addition of an admixture during the mixing of the cement.

integrated ceiling A suspended ceiling system in which the acoustical, illumination, and air-handling components are combined as an integral part of a grid system.

intelligent building A building that has a fully-integrated control system in which building services are monitored and controlled by a computer-based management system.

intercepting chamber A manhole.

intercepting drain A drain located between coupled the water source and the protected area.

intercepting sewer A sewer which receives the dry-weather flow from a number of branch sewers or outlets (and sometimes a determined quantity of storm water).

intercepting trap Same as interceptor.

interceptor A device to trap, remove, or separate deleterious, hazardous, or undesirable matter (such as oil, grease, gasoline, sand, and sediment) from normal waste conveyed through it, permitting normal sewage or liquid wastes to discharge into the disposal terminal by gravity.

intercolumniation 1. The clear space between two adjacent columns, usually measured at the lower parts of the shafts. 2. The system of spacing between columns which determines the style: pycnostyle, 1½ diameters; systyle, 2 diameters; eustyle, 2¼ diameters; diastyle, 3 diameters; areostyle, 4 diameters.

intercom See intercommunication system.

INTERCOM On drawings, abbr. for “intercommunication system.”

intercommunication system A communication system within a building or group of buildings with a microphone for speaking, and a loudspeaker for listening, at each of two or more locations.

interconnection Any physical connection or arrangement of pipes between two otherwise separate building water-supply systems whereby water may flow from one system to the other, the direction of flow depending upon the pressure differential between the two systems; also called a cross-connection.

inter-crimp In wire cloth, extra corrugations in the wires between points of crossing; usually applied to fine wire cloth having a wide mesh, to assure proper locking of the wires.

intercupola 1. The space between two cupolas. 2. The space between two shells of a cupola.

interdentil The space between two dentils.

interdome The space between the inner and outer shells of a dome.

interduce Same as intertie.

interface The common boundary, often a plane surface, between two bodies or materials.

interfenestration The space between windows in a façade consisting chiefly of the windows with their decorations.

interfilling Same as infilling.

interglyph The space between two grooves or cuts, as in a triglyph; usually a flat surface below which the groove itself has been sunk.

intergrown knot, live knot A knot whose growth rings are intergrown with the surrounding wood.

interior casing See inside casing.

interior chimney A chimney that is built within the walls of a structure; often categorized according to its location, for example, an end chimney; compare with exterior chimney.

interior design In a building, the planning, decoration, and furnishing of the interior.

interior door A door installed in an interior wall of a building, separating rooms or spaces within it.

interior finish The exposed interior surfaces of a building, such as plaster or wood, or applied materials such as wallpaper, paint, or trim. Interior finishes may be classified according to an ASTM test for the surface burning characteristics of building materials, class A being the best and class E being the poorest in ability to resist fire propagation.

interior fit-out The installation of ceilings, floors, furnishings, and partitions of a building, as well as the installation of all required building services.

interior glazed Said of glazing that has been set from within a building.

interior hung scaffold A scaffold suspended from the ceiling or roof structure.

interior lot A lot bounded by a street on one side only.

interior plywood A plywood, bonded with glue, that has limited moisture resistance; not durable when exposed to frequent or continuous wetting.

interior stair A stair, within a building, that serves as an exit required by code.

interior trim, inside finish Trim used on the interior of a building, esp. around door and window casings, baseboards, stairs, etc.

interior wall A wall within a building, entirely surrounded by the exterior walls.

interjoist The space between two joists.

interlace, entrelacs An ornament of bands or stalks elaborately intertwined, sometimes including fantastic images. Also see knot.

interlaced arches See interlacing arcade.

interlaced fencing, interwoven fencing, woven board Fencing made from weaving thin, flat boards together.

interlacement band Same as guilloche.

interlacing arcade Arches resting on alternate supports in one row, the arches overlapping in series where they cross. Also see intersecting arcade.

interlayer The plastic layer between two sheets of glass in the manufacture of laminated glass.

interlocked Two or more components, members, or items of equipment which are arranged mechanically or electrically to operate or to be placed in some specific relationship with each other.

interlocked grain, twisted grain Wood in which the fibers are angled in different directions every few annual rings; produces ribbon-stripe grain when quartersawn.

interlocking joint 1. A form of joggle in which a rib or other protrusion on one stone complements a routed groove or slot on another; prevents relative displacement. 2. A joint formed between sheet-metal parts by engaging their edges which have been preformed to provide a continuous locked splice.

interlocking tile A single-lap tile made so that an edge of one tile fits under a groove along an edge in the next tile in the same course.

intermediate course Same as binder course.

intermediate floor beam In floor framing, any floor beam between the end floor beams.

intermediate joist One of a number of full-length common joists, running from one wall to the other, on which floorboards are laid.

intermediate landing A horizontal platform between flights of stairs separating two floors.

intermediate metal conduit (IMC) See electrical metallic conduit.

intermediate post A vertical post that is similar in function to, but smaller than, a principal post.

intermediate rafter See common rafter.

intermediate rail A horizontal member of a door which is between the top rail and the bottom rail.

intermediate rib 1. A rib in vaulting subordinate to the primary ribs. 2. In a sexpartite vault, the transverse rib in the middle of the bay, above the intermediate and smaller piers.

intermediate stiffener Any one of the stiffeners on a beam or girder between the end stiffeners.

intermediate-temperature-setting adhesive An adhesive that sets in the temperature range 87° to 211°F (31° to 99°C).

intermediate truss The center truss of a three-truss span.

intermetium In an ancient Roman circus, a long barrier running down the arena between the two metae.

intermittent-flame-exposure test Part of an ASTM fire test of roof coverings; specified gas flames are applied to the test specimen for 3 to 15 cycles, according to the classification of roof covering.

intermittent weld A weld whose continuity is broken by recurring unwelded spaces.

intermodillion The recess between two modillions.

intermutule The space between two mutules, as in an architrave.

internal dormer A vertical window in a sloped roof; unlike the usual dormer window, it is not covered by a small pitched roof, but projects down from (and is set below) the slope of the main roof.

internal drainage The removal of water (for example, by weep holes) that has penetrated the exterior layers of a composite wall.

internal glazing Glazing installed in internal partitions. Also see inside glazing.

internal lining A lining of the internal surfaces of an HVAC duct with an incombustible acoustical material, such as fiberglass, so as to attenuate the transmission of airborne sound along the interior of the duct.

internally fired boiler A boiler whose furnace is wholly or partly surrounded by water.

internal-partition trap In plumbing, a trap, 1 forming a seal by use of an internal partition; usually considered undesirable because of the possibility of holes developing in the partition.

internal-quality block A masonry block suitable only for concealed work.

internal-quality brick Brick suitable only for concealed work.

internal stress The stress that exists in a component (for example, at a joint) in the absence of applied external forces.

internal thread Same as inside thread.

internal treatment Water treatment by chemicals fed into a boiler rather than into the water before it enters the boiler.

internal vibration Energetic agitation of freshly mixed concrete by means of a vibrating device which is inserted into the concrete at selected locations.

intern architect One pursuing a program of training in practice under the guidance of practicing architects, with the objective of qualifying for registration as an architect.

International Code Council (ICC) An organization that is the consolidation of the BOCA, ICBO, and SBCCI.

International Conference of Building Officials (ICBO) An organization that produces a widely-used model building code in the US. Home office: Whittier CA 90601-2298.

International Revival A term occasionally used to describe a 1970s adaptation of the International style that emphasizes the use of pure geometric forms.

international rubber hardness degree A measure of hardness, the magnitude of which is derived from the depth of penetration of a specified indenter into a test specimen; 0° represents a material showing no measurable resistance to indentation, and 100° represents a material showing no measurable indentation.

International Standards Organization, International Organization for Standardization (ISO) A body which promotes the development of world-wide standards and which publishes such standards.

International style An architectural style that is minimalist in concept, devoid of regional characteristics, stresses functionalism, and rejects all nonessential decorative elements; it emphasizes the horizontal aspects of a building; developed during the 1920s and 1930s, in western Europe principally in the Bauhaus school, and also in America. Buildings in this style are usually characterized by simple geometric forms, often rectilinear, making use of reinforced concrete and steel construction with a nonstructural skin; occasionally, cylindrical surfaces; unadorned, smooth wall surfaces, typically of glass, steel, or stucco painted white; a complete absence of ornamentation and decoration; often, an entire blank wall; often a cantilevered upper floor or balcony; open interior spaces; a flat roof without a ledge; eaves that terminate at the plane of the wall; large areas of floor-to-ceiling glass or curtain walls of glass; metal window frames set flush with the exterior walls, often in horizontal bands; casement windows; sliding windows; glass-to-glass joints at the corners, without framing; plain doors that conspicuously lack decor rative detailing. Houses are commonly asymmetric; in contrast, commercial buildings in this style are not only symmetric, but appear as a series of repetitive elements.

International System of Units (SI) A system of units based on the following fundamental quantities: metre, kilogram, second, ampere, kelvin, candela, and mole.

interpier sheeting Horizontal sheeting (usually wood) placed horizontally between underpinning pits; used where continuous underpinning is not required.

inter pit sheeting The interpier sheeting which is between concreted underpinning pits.

interrupted acoustical ceiling A discontinuous, suspended acoustical ceiling; the top of a partition extends through the upper surface of the ceiling. The partition may or may not extend upward to the overhead structure.

interrupted arch A segmental pediment whose center has been omitted, often to accommodate an ornament.

interrupted arch molding A common Norman molding consisting of a series of interrupted arches.

interrupted foundation A foundation, 1 that consists of individual pilings or piers.

interrupted shear wall A shear wall that is not continuous from the top of the wall to its foundation.

intersecting arcade Arches resting on alternate supports in one row, the arches meeting on one plane at the crossings. Also see interlacing arcade.

intersecting gable See cross gable.

intersecting tracery Tracery formed by the curving upward, forking, and continuation of the mullions, springing from alternate mullions or from every third mullion and intersecting each other.

interstitial condensation Condensation of water vapor within an element of a building, e.g., within a wall.

interstitium The crossing, 1 in a cruciform church.

intertie In framing, a horizontal member, between the sill and head, which extends from one stud to the next in order to stiffen them.

inter-tie Same as nogging piece, 1.

intertriglyph The space between two triglyphs in a Doric frieze; a metope.

interval tower One of many towers situated along the length of a curtain wall, 2.

interwoven fencing See interlaced fencing.

intgl Abbr. for “integral.”

intonaco The fine finish coat of plaster made with white marble dust to receive a fresco painting.

intrados The inner curve or face of an arch or vault forming the concave underside.

intruder alarm system Same as burglar alarm system.

intumescence The process of swelling up, as with the application of heat, such as vermiculite that is heat-treated for use in thermal insulation.

intumescent Said of a material that swells and chars when exposed to flame and that forms an insulating fire-retardant barrier between the flame and material.

intumescent paint Paint that swells and chars when exposed to flame, thus making the surface more fire-retardant.

inverse condemnation A legal doctrine holding that, in certain circumstances, where private property is destroyed or substantially diminished in value by government action, the conduct of the government is regarded as the taking of the property and the owner of the property must be compensated in fair value by the government.

inverse-square law A law which applies to a light source (or to a sound source) that is in a space far away from any reflecting surface: the intensity at a point, as measured on a surface which is perpendicular to a line drawn between the point and the source, varies inversely with the square of the distance between the point and the source. (For sound waves, this decrease in intensity is equivalent to a drop in sound-pressure level of 6 dB for each doubling of distance from the source.)

invert In plumbing, the lowest point or the lowest inside surface of a channel, conduit, drain, pipe, or sewer pipe.

inverted arch An arch with its intrados below the springing line; esp. used to distribute concentrated loads in foundations.

inverted joint A fitting, 1 which is turned upside down, reversed in position, or turned in an opposite direction.

inverted roof A roof membrane whose thermal insulation is above, rather than below, the membrane.

inverting ballast A lamp ballast, 1 designed to operate on direct current.

invisible hinge A hinge so constructed that no parts are exposed when the door is closed.

invitation to bid That portion of the bidding documents which solicits bids for a construction project. Also called an invitation to tender.

invited bidders The bidders selected by the architect and the owner as the only ones from whom bids will be received.

involute 1. A curve traced by a point at the end of a string as the string is unwound from a stationary cylinder. 2. Curved spirally.

inwrought Closely combined or profusely embellished.

Ionic 1. Pertaining to, or characteristic of, Ionia, the eastern part of the Greek world. 2. Same as Ionic order.

Ionic capital The topmost member of a column of the Ionic order; the twin volutes in the Greek Ionic order are larger and more conspicuous than the corresponding volutes in the Roman Ionic order.

Ionic order One of the five orders in Classical architecture, originated by the Ionian Greeks. Usually characterized by columns usually having 24 flutes separated by narrow fillets; an entablature, a frieze without triglyphs; dentils in the cornice; elegant detailing; less elaborate than the Corinthian order and less heavy in appearance than the Doric order. Pilasters in the Ionic order often have fluted shafts with a capital consisting of a band of anthemions, with egg-and-dart moldings above.

ionization-type detector A type of fire detector that uses a radioactive source to develop a current across an air gap within the detector; when products of combustion enter the detector, they alter the flow of current and activate an alarm; particularly useful where early-warning detection is essential either because of special safety requirements or because protection is required for property of high value.

IPS 1. Abbr. for “iron-pipe size”; a nominal dimension, inside diameter. 2. Abbr. for “International Pipe Standard.” 3. Abbr. for “inside pipe size.”

IR Abbr. for “inside radius.”

iridescent glass A translucent glass having an iridescence similar to that of a soap bubble; see opalescent glass.

Irish moss An Atlantic Coast seaweed; used to make size for paint.

iron A ductile metallic element from which pig iron and steel are made; used in its relatively crude form for making tools, castings, and so on. Also see bar iron, cast iron, malleable iron, ornamental iron, wrought iron.

iron back A cast-iron fireback.

iron blue See Prussian blue.

iron cement A cement composed of cast-iron borings or filings, sal ammoniac, and additives; used for mending or joining cast-iron parts.

iron core Of stairs, a steel bar enclosed by a wooden handrail.

iron framing A system of structural ironwork for buildings, first developed at the end of the 18th century. The Crystal Palace, constructed in New York City in 1853, provided a dramatic example of its application in America. Also see cast iron and cast-iron front.

ironmongery (Brit.) A term for hardware, particularly that used for doors and windows.

iron oxide A principal ingredient in a family of inorganic pigments, ranging from yellow through red and from purple to black; used extensively in paints.

iron pipe size The nominal inside dimension of a pipe.

iron titanate See ilmenite.

ironwork Objects or parts of objects made of cast iron or wrought iron; initially utilitarian, later often elaborate and ornamental; also see cast-iron lacework.

irradiance The density of the luminous flux which is incident on a surface.

irregular pitch A roof whose slope is not constant.

irrigation pipe Any type of pipe through which water is distributed for irrigation.

irrigation system See lawn sprinkler system.

Isabelline architecture See Plateresque architecture.

Isabellino style A style of Spanish architecture popular during the reign of Isabella and Ferdinand (1474–1516).

I-section A rolled or extruded structural metal beam that resembles the capital letter I in vertical cross-section.

Islamic architecture, Muslim architecture The architecture of the peoples of Islamic faith, also called Mohammedan, which from the 7th century onward expanded throughout the Mediterranean world and as far as India and China, and beyond, producing a variety of great regional works and local decorative styles. It is characterized by domes, horseshoe and round arches, tunnel vaults and richly decorated ornamentation which is geometric because of the ban on human and animal representation. Also see Muslim architecture. (See illustration p. 548.)

island In the design of a parking lot (car park), a raised area having a curb, so located to separate traffic lanes and/or to guide traffic.

island-base kitchen cabinet A free-standing kitchen cabinet placed below a counter or work surface; the ends of the cabinet are exposed.

ISO Abbr. for International Standards Organization.

isocephalic In bas-relief, having the heads nearly on a horizontal line; esp. said of the heads of human figures in a frieze or band.

isodomum In ancient Roman masonry and Greek, an extremely regular masonry pattern in which stones of uniform length and uniform height are set so that each vertical joint is centered over the block beneath. Horizontal joints are continuous, and the vertical joints form discontinuous straight lines; opus isodomum.

isofootcandle line See isolux line.

isolated Said of a space not readily accessible to persons unless special means for access are used.

isolating strip Same as expansion strip.

isolating switch A switch for isolating an electrical circuit from its source of power; it is intended to be operated only after the circuit has been opened by some other means.

isolation joint A joint, such as an expansion joint, between two adjacent structures which are not in physical contact.

isolation strip Same as expansion strip.

isolation transformer In an electrical system, a transformer that prevents one section of the system from undesirably influencing another section.

isolator See vibration isolator.

isolux diagram See isolux line.

isolux line A line through all points on a surface where the illumination is the same; called an isofootcandle line if the illumination is expressed in footcandles. A series of such lines for various illumination values is called an “isolux diagram.”

isometric drawing A form of three-dimensional projection in which all of the principal planes are drawn parallel to corresponding established axes and at true dimensions; horizontals usually are drawn at 30° from the normal horizontal axes; verticals remain parallel to the normal vertical axis.

isothermal Said of a process which takes place at constant temperature.

isotropic Said of a building material that has the same physical properties in all directions.

IST Abbr. for inside trim.

IstructE A designation for the Institution of Structural Engineers in London.

ISWG Abbr. for “Imperial standard wire gauge.”

Italianate style An eclectic style of Italian-influenced residential and commercial architecture; fashionable in England and America from the 1840s to around 1890. Italianate style residential buildings may be classified as: Villas: Domestic architecture intended to resemble prosperous farmhouses or country manor houses of northern Italy; usually two stories high, with an attic story; Town houses: Urban row houses, commonly three or four stories in height with a flat or very low-pitched roof; mullions divide both the upper and lower window sashes vertically into two panes. Commercial Italianate style buildings: a raised pediment above the roofline at the center of the façade, often with the name of the building and/or the date of its completion, and a cast-iron façade. Palazzi: See Italian Renaissance Revival.

Italianate style buildings are commonly characterized by a two-storied structure with exterior wall surfaces of smooth ashlar masonry, and rough-cast brick, stucco, or wood clapboard siding; classical columns, and pilasters; balustraded balconies; a belt course encircling the building; wide, projecting cornices with decorative brackets for support; corner quoins; a square tower; a porch; a gabled roof and/or hipped roof; a cupola or belvedere, chimney shafts with ornate caps; narrow double-hung window sashes commonly having arched (rather than rectangular) upper sashes; windows often topped with a segmental arch, with a hooded crown, or with a crown supported by decorative brackets; a pair of decoratively paneled double doors at the main entrance, the upper parts of which are glazed; often, a round-topped door or a door set in a round arch. The latter phase of Italianate style, sometimes referred to as High Victorian Italianate, is usually more highly decorated than its earlier counterpart. Also see Tuscan Villa style.

Italian molding A wide, heavy bolection molding, often used to surround a fireplace.

Italian order Same as Composite order.

Italian Renaissance Revival An architectural style emulating the Renaissance palazzi of Northern Italy; most popular from 1800s to about 1930. Buildings in this style are usually characterized by façades that are commonly symmetrical and essentially flat; rectangular or square in plan; usually two or three stories high; masonry or stucco walls; a different architectural treatment on different stories; an elaborate belt course between stories; a massive cornice that rests directly on the architrave (the frieze being omitted); pilasters, rusticated quoins, dentils, and decorative detailing; a recessed entry porch flanked with classical columns or pilasters; prominent arcading on the ground floor of public buildings and a recessed arcaded gallery on the floors above; commonly, a low- to moderate-pitched, ceramic-tiled hipped roof; widely overhanging eaves with decorative brackets below; occasionally, a flat roof with a balustrade or roofline parapet above an elaborate cornice; commonly, a different type of window on each story; on the ground floor, elaborate, tall, narrow windows placed in a regular pattern, set symmetrically on both sides of the main entrance; the second-story window heads often pedimented and supported by ancons in elaborate buildings; windows on the uppermost story are usually the smallest and simplest, being square in shape; arches frequently above exterior doors; a hooded entryway; an entablature, supported by pilasters, over the entrance. Sometimes called Italian Renaissance style or Second Renaissance Revival, this style is occasionally subdivided into the North Italian or Venetian mode and the Romano-Tuscan or Florentine mode.