Our passive solar, ‘glass and mass’ design called for an open front face, lots of double glazing and orientation south to maximise solar gain.
Orientation of a home, combined with heavy walls, enables passive energy gain from the sun. This is an old idea.
Town planners in ancient Greece used this simple aspect of natural design to gain both light and heat.
In Brittany, many of the early houses are aligned just a few degrees east of south to maximise solar gain. This is bioclimatic architecture. In the northern hemisphere the sun rises in the east and sinks in the west and so a building facing south will gain most from the sun. Over the year of the build, it felt good to follow the sun as it tracked across the horizon in front of the house – highest at the summer solstice and then gradually sinking lower until mid winter.
For three days after winter solstice, the sun remains at the same point, neither sinking nor rising. Then the ‘light of the world’ is born again on the 25th December, and begins its gradual climb in the sky back to mid-summer.
The front face and trifold doors are supported on a concrete footing that runs the full length of the building. The trifolds fit in the space between the hefty douglas fir uprights and an engineered wooden beam that runs along the top of the front face. Inch by inch, using notched A frames, we slaved and lifted the beams skywards…
Some Technicals on the Groundhouse Roof
The main roof structure comprises 23 ibeams specified and supplied by Finn Forests. These lock onto the front ‘kerto‘ front face beam with heavy duty simpson joist hangers. The kerto comprises 2 x 90mm beams that bolt together and lock onto the ‘heartwood’ douglas fir uprights that support the roof and the doorframes. Between each ibeam we fitted 330 mm of high performance ‘non itch’ eco insulation from YBS Insulation. This was selected because it is manufactured from recycled plastic bottles. A heat reflecting vapour membrane called dupont airguard is fitted above the plasterboard of the ceilings and the roof void is vented at the top. The roof covering is TPO supplied by Flag UK, which is suitable for potable drinking water collection, versatile and very durable. The rotunda was slated by a local artisan and we incorporated salvaged copper for guttering and capping. We also used sheeps wool insulation from Second Nature.