Garage slab side insulation protection
Hi,
I am building a garage on a thickened edge slab in Minnesota. The slab is insulated underneath with rigid foam insulation and vertical foam insulation along the sides.
My garage will have 2×6 walls and the foam insulation on the side of the slab will be exposed 4 or so inches above ground. In order to protect the insulation, I plan to have treated plywood sheets extend from the bottom of my wall into the ground 6-8 inches. I have attached a picture that illustrates this with two boards, one simulating the wall plate and the other the treated plywood extending down into the ground.
Questions:
1. The foam insulation around my slab is not even, and will require trimming to make the treated plywood sheets fit when we tip the wall up in place. Does anyone have a suggestion on how best to trim the thickness of the foam?
2. Does anyone see any problems with my plan to use treated plywood sheets to protect the insulation in this way?
Thanks much for your help!
Replies
Treated plywood? How treated is it really. Normal “treated” ply can and will separate and decay over the years. What grading of ply are you able to find?
You would be providing a path for subterranean termites to reach your framing unobserved. The safest solution is to use sheet metal under the plate and bent down to cover the foam. The best solution is to not cover the edge of the slab. This is one of those situations where two building practices are in conflict. I don't know if you have subterranean termites in your area but as far as I have been able to find out they are a problem nationwide.