Permanent wood foundation (PWF) backfill height?
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All the documentation I’ve found on PWF basements never shows insulation under the slab floor. The allowed back fill heights are always referenced to the bottom of the bottom plate of the wall which coincidentally is the bottom of the slab.
If under slab insulation is installed after the perimeter PWF walls are in place, the slab will be raised by the thickness of the insulation. With under-slab insulation is the backfill height the height above the slab bottom? or the bottom of the bottom plate?
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Replies
Jerry,
The difference is only 3 or 4 inches, right? My own reaction is that you are overthinking this. Backfill heights change by 3 or 4 inches all the time -- all it takes is a homeowner to add a flower bed near the foundation to end up with 3 more inches of topsoil. I don't think this matters much.
-- Martin Holladay
The difference could be 7 or 8 inches if perlite ,in bags, was the insulation.
When I was an apprentice carpenter, we installed several Preserved Wood Foundations and they were smelly. Have they changed? I wonder how much VOCs they emit?