I’ve built an offgrid home in Cochise county AZ, the county has an alternative builders program whereby for an extra $500, you can opt out of all inspections and build whatever you want. I built an earthbag home- the walls are earthbag, and the roof is a series of intersecting catenary vaults made from ferrocement. I’m experimenting with aircrete but my well water seems to hard to make lasting foam.
Posts made by Annesley
RE: Aircrete home AZ- codes and zoning
RE: Rocket Mass Heaters
I would beg to differ as regards aircrete being ideal for the riser. Portland cement and soap are not refractory materials- even concrete cannot be used in high heat situations as it crumbles. I’ve built three rocket mass heaters, the first two I designed from watching YouTube but the designs didn’t work well once the stove was fired up. Third time’s a charm- I bought a book on rocket mass heaters written by a group that has built over 700 of them. The riser is fire brick to withstand the severe temps in the bell and it’s insulated with refractory rated rock wool. Normal bricks just crack apart in the heat. Most people use a steel drum for the bell but I used a 60 gallon well pressure tank, much thicker steel. Got it from a local scrap metal yard.
It works well with nearly constant feeding. The wood burns quicker than in a traditional wood stove and the firebox is small because it’s engineered to have the same dimensions as the exit pipe, which according to the book I have, says 8” pipe works better than 6”
RE: Aircrete and earth-berming
I built an earthbag home with intersecting vaults of ferrocement as a roof. I’m still experimenting with aircrete- did not want to use foam because it’s been implicated in the deaths of firemen and occupants due to the hydrogen cyanide gas that’s released when the stuff burns. I’ve been going for fireproof as opposed to flame resistant. No fire district where I live.
I’m on well water and the water is hard which seems to be causing my attempts at aircrete to fail so far...
In terms of a hobbit house that can actually heat and cook itself with the sun and earth, something resembling an earthship would be good- greenhouse for food and to heat the home without other inputs even in harsh winters. But tire wall construction is very laborious and I’ve found with earthbags I need to cover the bare bags so in effect attach stucco wire to both faces. It would be far easier to build two ferrocement walls with a gap and backfill / tamp earth into place. Or simply start with a ferrocement shell and bury it- ferrocement is famously strong. I would insert photos but that feature isn’t working with my phone. I’ve got many photos of the construction process at my non commercial, personal blog: TypeThisToSeeIt.com)
RE: aircrete vs. ferrocement
I built my home with earthbag walls and intersecting ferrocement catenary vaults for the roof. I was hoping that I would have enough thermal mass for the structure to perform like an earthship. The mass warms from an attached greenhouse as the only heat source even with winters that can reach 30 below F. Mine doesn’t but earthship regularly do-
I’m hoping to cover the 1,200 sq foot multiple-domed roof with aircrete. I didn’t want to use foam because it can burn and has been implicated in causing heart attacks among first responders and occupants, due to the cyanide gas released when foam insulation burns.
Also, there is no fire district where I live so I’ve built with being fireproof in mind.
My question regards how well I can make aircrete blocks adhere to the surface of the ferrocement, which is coated with elastomeric paint, and whether aircrete is really waterproof. I read on the site that it and ferrocement are waterproof, which of course is incorrect- Portland cement is hygroscopic unless a waterproofing additive is used, which I have with the ferrocement. Otherwise, even concrete acts as a sponge to hold water and corrode any metal reinforcement as well as require deeper foundations where it freezes- because the trapped water will freeze and crack the concrete or cause spalling on roofs. Before Portland cement there was lime based mortars and old world homes built with stones and lime didn’t need to be concerned about water freezing inside the structural components because lime releases water, as opposed to absorbs. At any rate, I understand that the aircrete can support a man’s weight, I’m just wondering if an ideal solution would be a thin ferrocement coat over the aircrete- I’m hoping to have a stairway to the roof as the views are great, so having a sturdy roof seems very practical.
Lastly, I’ve heard of people using air entraining agents in cement to be able to pour at colder temperatures. Is it advisable to mix aircrete when it is below freezing? Thanks for any input.