Custom Victorian Greenhouse

One objection to most kit greenhouses is that they tend to have little going for them on the style front: a plain metal framework supporting clear panels. If you’re looking for a greenhouse project that blends with the look and character of your home, your best bet is to design and build one yourself.

The custom greenhouse seen in this project is designed and scaled to fit lean-to-style against a south-facing wall on an 1890’s era Victorian house. The principal design details that make it blend are the kneewall, which uses the same narrow wood lapsiding as the house, and the custom windows and door, which feature an arch element that is also present in the house trim. At roughly 6 × 9 ft. in floorplan, the greenhouse is on the small side. But a space-conserving built-in-bench helps the gardener who designed the greenhouse get maximum usage from this small space.

The glazing on the greenhouse is 1/4"-thick clear polycarbonate (See Resources, page 236). The roof panels are also clear 1/4" polycarbonate, but with a hollow twin-wall construction that resists shattering and limits condensation. The roof vents are operated by lift arms with integral thermometers. When the air temperature inside the greenhouse hits around 85° the vents pop open automatically. The windows and the door are custom-made by sandwiching polycarbonate panels between wood frames. To allow for movement of the materials, the frames are bolted together through oversized bolt holes. All but one of the windows are hinged on the tops so they can swing open to enhance ventilation.

Construction note: The greenhouse seen here features a poured concrete slab that is set apart from the house by an isolation joint. The back wall studs and roof panels are not connected to the house either, thus the greenhouse is technically a freestanding structure. Gaps between the greenhouse and the house are covered with various flashings, each of which is connected to one of the structures only. This has several advantages: primarily, it allows the structure to move and shift slightly (thereby avoiding cracking of glazing and roof panels) as the soil conditions and temperature change. And if the structure is small enough and has adequate setback distance from your property lines, you likely will not need a building permit. If the greenhouse were connected to the house, you would be required to dig full frost footings, as well.