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Straw bale foundation on massively rocky ground

 
Alisha Corp
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Hello everyone! I am wanting to build a straw bale house but I have a problem. My ground in on a classic Arkansas land with literally a big rock underlay and many many other small rocks. Trenching for the foundation and other such needs for digging is mostly out of the question. I know that I need some big machinery buy money hinders they opportunity so I was curious if anyone had any ideas on how I could solve the dilemma.
 
Dale Hodgins
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Jay C. White Cloud
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Hi Alisha,

Dale's wisdom on this is 100%. Much that is out there about "frost heave" is more "myth" than it is an actual environmental event. Clay soils expanded with just water added, and in some types enough force to split stone...no need for freezing...However combine the two (water and freezing) and you get incredible expansion pressures (aka heave.) If water can drain, like with sand/gravel or is "drained away" like over stone bedrock, then there is not "heave."

Now, as for a foundation...it sounds like nature has given one to you already?? Bedrock is a wonderful thing to build off of just as it is in most cases. There is no need to do much to it at all accept create the appropriate armature of frame work (I recommend wood) to get your SB above grade the appropriate distance. This can be achieved with a "raised earth" foundation system, stone work, or simple wood posts scribed to the bedrock and insulated floor. Those are some to the "basic forms." There are variations of each and others as well that all fit within the parameters of "natura/traditional" building.

Good luck...
 
Dale Hodgins
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If you do anything that encases the stone, such as a concrete foundation, it's necessary to check for radon gas. With any sort of pier system, where the floor sits above grade, radon will not be a problem.
 
Jay C. White Cloud
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OOOOH...Oooh!!! Radon!!!

Thanks Dale!! I plumb forgot about that warning...My bad!!

That is a big deal and very dangerous in some areas...Even with alleged good "venting" encapsulated bedrock/stone spaces with concrete stem wall basement foundations or even slabs does not warrant the risk to me to human long term health. Concrete, beside being a environmentally damaging materials to build with, does not "block" radon intrusion/infiltration into living spaces. Granites are notorious for this having issues with radon.

I would still build of a granite bedrock, but would only employ certain natural foundation modalities to do so. As Dale has correctly suggested a "raised post on plinth (or bedrock) foundation would be my first choice and then there is virtually zero risk...
 
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