Glenn Herbert wrote:Filling 8" concrete block with concrete does not require vibrating to get decent results; a few small voids will have negligible effect, and there is no surface for appearance to matter. Rodding each core to make sure the concrete has filled it is sufficient. I run a pair of 2x4s along the top of the dry-laid block (usually surface-bonded first for stability ) with 1/4" threaded rod to tie them together and clamp them to the wall. This leaves a 3" deep x 8" wide channel on top of the wall that is easy to guide concrete into and convenient for horizontal rebar. Trying to pour half of a wall with concrete and then continue it up and pour the other half pretty much doubles the labor.
I have the rebar in the slab bend and extend up out of the slab 2-4 feet where the walls are going to go, lay up the block several courses, then wire on rebar for the full height of the wall (which makes laying the rest of the block more tedious, lifting many of them up to 8' high.) You can also just lay up the block and drop 8' lengths of rebar into the cores that have 2-4' stubs and trust that the continuity will be sufficient. It takes more rebar but is easier. I use #3 rebar for these structures because it is easy to bend and tweak to fit the block. I make up for the smaller than ordinary size by running more of them, thus distributing the reinforcing more evenly in the wall. I feel this is a net gain. If you are a professional with heavy duty bending tools, this may not be the best tradeoff.
A 4' berm would be enough to protect footings in ordinary cold climates, unless your standard frost depth is greater than that. I would want to insulate all of the walls anyway to avoid massive heat loss in winter and cold sweaty walls in summer, then backfilling as high as practical to minimize exposed walls.
R Scott wrote:
scott thompson wrote:
S Bengi wrote:Here is floorplan view:
http://www.naturalbuildingblog.com/wp-content/uploads/2012/05/Solar-Pit-House-PDF.pdf
nice design.
I plan to attach a green house and garage to my structure that can be accessed by doorway to each area. while I do like the idea of food production in my home I wanted to be able to grow more than just a couple of planters so that I could rely more on my own production.
I will probably go with a vertical glass from instead of the slanted front. the slanted never really appealed to me. steel roof over living roof so I can capture rain water. it will be a combination of a couple different construction methods. cmu and timber frame. timber frame just because Ive always love the look plus I want to be able to build from resources off my lot as much as possible.
thanks for sharing your designs. I appreciate your insight.
That sounds just like my design.
Even the new earthships use vertical glass. The marginal gain is not worth the additional maintenance, plus it voids the window warranty.
S Bengi wrote:Here is floorplan view:
http://www.naturalbuildingblog.com/wp-content/uploads/2012/05/Solar-Pit-House-PDF.pdf
Glenn Herbert wrote:Yes, a berm will protect a footing at original grade level. It effectively raises grade and the frost line by the height of the berm (a bit less if the berm is steeply sloped close to the wall).
You still need to remove topsoil or sod down to solid dense subsoil, so the footing will not settle too much or unevenly. If you are going to use concrete and cmu, you might look into the scandinavian concept of frost-protected shallow foundations. This as illustrated in the link will be effective for exposed walls. For bermed walls, I have used a variation with a slightly thickened slab edge and rebar continuous in the slab and bending up into the cavities of the cmu, which are then filled with concrete to make a monolithic reinforced concrete structure. This has effectively held up fully backfilled basement walls for 30+ years in my direct experience with no sign of deterioration. I would use a 6" slab thickened to 8 to 10" at the edges for safety.