We’re planning to build on a site that has medium expansive soils. I have 20 years plus in the trades (mainly carpentry) and plan on building our new home with the help of my two teenage sons (they’re excited about it!). We will have a soils test done and an engineered foundation regardless of the material type we choose. It would save money (I think) to build with concrete block since we have the ready-made family crew. It will be a passive solar home bermed on 2 1/2 sides. We are considering building all interior and exterior walls from block primarily for the thermal mass. Questions: If the footings and block walls are built to engineered specs, is poured concrete still better? Has anyone heard of building the outside walls of poured conrete and laying up the inside walls with block? What about dry stack block with reinforcement and poured cores? All opinions appreciated!
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You've got a lot of questions and it might do you some good to try the advanced seaarchj function for some of the subjects.
Think about IDFs for the exterior walls. That way you get the advantages (yes concrete is stronger when reinforced with steel rebar) of reinforced concrete and the insulation that passive solar needs. It can be easier to do for a family project, too. Living in an ICF house is very quiet too.
As long as you have provided for the interior walls with the foundation, there is no problem doing them with CMUs
I hate stack'n'bond because I've seen too many failures.
No matter what type wall you use, don't place expansiver soild back against the walls for backfill. Use gravel to let water drain so you don't have frost heaving the walls in or cracking them.
Excellence is its own reward!
I remember seeing an article about wood foundations in either Fine Homebuilding or the Journal of Light Construction. I was intrigued because as a framing sub I could do the foundation myself. The walls were made out of 2x8 and it was sheathed with 3/4" plwood all treated of course. The advantages were the ease of insulating a wood wall and running wire , plumbing etc. I realize you hadn't considered this option but it would complement a solar design .
It wouldn't give him thermal mass though for heat storage, and wood foundations must be properly designed and balanced and drained to wwork right. Most passive solar designs are not symetrical or typical in many ways, which would challenge the design parameters of wood foundations..
Excellence is its own reward!
Thank you for your suggestion. I have built AWWF foundations a couple of times and like the ease for us framing oriented types. Piffin is right about the low available mass, now there are new concerns about mold in such buried framing, and, if I understand correctly, the law changes soon that will end the type of treating that we are used to on "green" treated.
Hasbeen, I guess I will have to find the article I was alluding to in my post. I know it was in the last year or so and I don't recall any concerns about mold. Anyways I was just throwing something out there F.Y.I.