Hey yall! I'm brand new here, but have been doing reading here and elsewhere for years now. I've long dreamed of building an all natural, passive solar home for myself that would entail a small living space and a large workshop. More recently I'm getting to a point where I may actually have the cash to start building things, so I'm trying to get realistic about what is possible. To that end I really want to start with building a small workshop of bale and cob with a round-pole living roof to figure out how viable my plans might be. I live in Western Massachusetts and the space I have available isn't viable for passive solar, so I'm starting with a fully enclosed and insulated build. My plan is straw bale walls, packed with cob and covered with about 6 inches of cob on either side (also known as bale-cob), with corner cob pillars (2'x2') and cob pillars at minimum every 6 feet along the walls. The roof would have a 1:12 pitch and it would have earthen floors. All on a concrete bound stone stem wall (1.5') and a rubble trench foundation with a drain pipe at its base. Heating would be accomplished with an RMH with a cob bench.
I have extensive construction experience and have worked with natural materials in the past for exterior landscaping projects, just never to build a structure. I would be doing all of the work myself with no hard limit on how long it takes me.
The big thing I have yet to figure out is how to insulate the roof. I'm totally fine with leaving the ceiling open, especially since this will be a workshop. I've found suggestions here to use spray foam or to lay foam board above the roof cladding, but under the EPDM liner, but I really want to avoid those materials. I'd prefer to use wool or rockwool, but I'm concerned about moisture. If I use one of those materials secured with battens or furring strips to keep it against the roof will that be adequate to keep it dry? Are there other downsides to that? Any other suggestions are very welcome!
Also if anyone has thoughts on other aspects of my plan I'd be more than happy to hear those too.
Thanks so much!
Keira
