The geodesic Growing Dome® sits on a 24″ insulated All-weather wood foundation wall, therefore raising the greenhouse up above the snow and providing increased headroom inside. The foundation wall contains high quality materials that withstand extreme weather. The materials also resist rot, decay, and termites. The wall comes standard with every Growing Dome greenhouse kit. Bending over or squatting to garden causes spinal problems and the internal raised beds, when built to match the foundation wall height, eliminate the need to do just that.
Insulated Wall Cavity
Soil, just like water in the Above Ground Pond, is a valuable source of thermal mass. In our year round greenhouses, the insulated foundation wall prevents the soil in the growing beds from losing heat on a cold winter night. The 2″ x 4″ foundation wall on the 15′ – 26′ Growing Dome provides enough space to insulate with R-10 2″ polystyrene foam board. The 33′ and 42′ Growing Dome use 2″ x 6″ lumber for the foundation wall, so this wall cavity may be insulated with two pieces of 2″ foam board. Each kit comes with spray foam, so any gaps in the insulation can be filled and sealed properly.
All-Weather Wood Framing
The foundation wall’s bottom plate and studs are made of ProWood® (a safe, pressure treated lumber) for added longevity. The lumber will resist rot and termites. ProWood has a Gold GREENGUARD and NGBS Green certification. Also, the wood treatment is a certified Environmentally Preferable Product. Most building departments require a pressure treated bottom pate for all structures, and the ProWood used in the foundation wall will meet or exceed those requirements. Visit the manufactures website for technical documents, if your local building department requests those details. To further protect the 24″ foundation wall, it is lined with galvanized sheet metal on the inside of the greenhouse.
Foundation Wall Siding
The Growing Dome comes standard with LP® Smart Side® panel siding. This material is durable, easy to install, and looks great. This siding material resists rot and termites. It also withstands extreme weather like hail, heavy rain, snow, intense heat, and freezing temperatures. Smart Side will certainly meet or exceed building department requirements. If your building department asks for specific documentation on the siding, check out the technical documents at the manufactures website.
The perimeter insulation is an optional frost barrier that prevents permafrost from creeping under the Growing Dome during the winter months. Our greenhouse designs feature a frost barrier of 2″ thick by 16″ wide polystyrene foam board insulation. Diagonally sloped away from the dome, the buried insulation spans the entire perimeter. It helps the mass of soil inside and under the greenhouse maintain an even temperature, despite outside fluctuations. Although the perimeter insulation is optional, Growing Spaces strongly recommends installing this frost barrier because it helps insulate the greenhouse.