I didn't know if this should go in this forum or the greenhouse one, but here goes. We have earth berms on our property, they are about 5-6' in height with sloping sides and at one point they form a corner - maybe about 120 degrees. This corner is well sheltered from prevailing winds and gets a lot of sun _south-westerly aspect). I am considering building a greenhouse type structure there, sort of a hybrid of earth-sheltered and roundhouse. I would like to use the berms to form about half of the circumference, then have the open face mostly glass - perhaps with cob walls a few feet high? And a reciprocal roof, with the north-sloping side as a green roof to provide insulation against north winds, and the south-facing side clear (glass or other). I've only just started thinking about this so I need to do a lot more research! What are the pros and cons of this type of building? Pros - sheltered from the wind, using the earth berms as a heat-sink, warmer than a polytunnel Cons - possibly costly and definitely hard work to build, making a permanent enclosed growing space comes with a host of potential problems in managing the microenvironment, etc
Specific questions I have at the moment are:
What to build the 'interior' walls out of - the walls against the earth berms? The berms themselves are too sloped to just use as-is. They are earth with large amounts of rock and some vegetation. I'm thinking to build some strong walls that won't rot, and then back-fill so that there is no space between the back of the wall and the berm, and the roof slopes right onto the berms. Can I build a wall of earth-filled tires? Should I go masonry? Would it be possible to build a wood or straw bale wall and wrap it in plastic? (because once I back-fill the earth against it, unprotected wood or straw will eventually just rot)
We are theoretically zone 9 though I have issues with the classification - essentially our winter is not very cold but it's long, and all year round is very very wet and windy.
Thanks! I did see that thread - it looks very similar to a ruined one at my parents' cabin back in the states, brought back memories! Did you mortar those rocks together or is it a dry stone wall? We do have rocks, but not enough to do that, we'd have to get more which might get expensive, I have no idea. Our village actually has a rather famous slate quarry - sadly long since closed. Most of the rock aside from the slate is bluestone (the same stuff in stonehenge!) - but not enough on our site unless we do some large-scale excavation and sifting.