Hi All,
I recently bought a renovation project that the previous owner lost to the bank. The existing structure is a slab on frostwall. I’m planning on pouring a new slab on top of the existing to a) level the floor and b) provide radiant floor heating on the first floor. I’m planning on starting with 6 mil poly, 2 layers of 2″ Styrofoam, the radiant tubing and 3″ of concrete. Ceiling height is not a problem. My concern is where the concrete will contact the exterior walls. I’m considering ripping 3/4″ PT plywood to run around the perimeter of the building and at interior walls. Anyone have any ideas?
Thanks
Bill
Replies
How will you handle the sheetrock on top of the ply? Oh wait, the top of the ply will be flush with the top of the new slab. You're talking about 7" gain. Why not use 2x8 blocking nailed flush with the face of the studs. But then the ply will probably install faster.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
how about 2" of vertical rigid foam to provide an appropriate edge thermal break?
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You really dont want wood in contact with concrete. It will rot the wood.
That's why I'm planning on using pressure-treated plywood. I need something rigid enough to pour concrete against. I suppose I could block all the stub bays and user 1" rigid foam, but that's a lot more work.
pt ply was developed for use in rot resistance(alkaline) situations, not for protection against the acids of curing concrete.
Rigid foam works real good.
pt ply was developed for use in rot resistance(alkaline) situations, not for protection against the acids of curing concrete.
??? acids in curing concrete? Even non-PT ply does fine as a concrete form. That's what foundation subs use. I see no reason why PT couldn't be used, and left in place when curing is complete.
PT ply was developed for permanent all-wood-foundation systems; it's impervious to rot (fungus) and insects, and does fine in both acidic and alkaline soil conditions.
You're right, I goofed. I was thinking of another product.
Just a suggestion two inch foam on exterior wall. Cut a 45 degree bevel in the top of the foam, so the crete goes closer to exterior walls. Some curing compound sprays eat foam like gasoline.