Cold climate foundation design
Building a single-family home in Anchorage, Alaska with hydronic in-slab heat and was wondering about below-grade insulation. Our ground usually freezes down to three or four feet, though it has reached ten feet before.
Most builders here doing hydronic slabs put R8 insulation around the exterior of the foundation and R10 below the slab and call it a day. I’m wondering whether it’d be a good idea to also put insulation on the inside of the buried wall (at right) and a wing of insulation out over the French drain. I’m thinking that this would help channel a lot more heat down to the footing to protect it from frost, and also retain heat to protect the French drain. Thoughts?
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