looking to build my first house... I pour concrete floors/walls for a living and want to stretch my money. I work for a big company and using there forms isn't an option. I heard of forming the foundation with 3/4 form ply and then using it on the roof. anyone ever do this or have any suggestions. thanks

That's pretty stout roof sheathing.

Posted By ICFHybrid on 02 Mar 2014 01:28 AM
That's pretty stout roof sheathing.

Yes, that is stout roof sheathing but it is a good reuse.

I'd say you'd want to clean it pretty well as I've noticed even a little concrete residue seems to attract moisture hygroscopically, and you don't want that on the sheathing.

i figured that if they needed a quick pressure washer bath, that would work. i'm seeing big savings in this process. no rental on forms... just the difference on 1/2" osb would be big.

Are you planning on finishing and insulating the basement? If so, have you figured in the costs for insulation and compared the costs of a poured basement wall with insulation to Insulating Concrete Forms (ICF) that remain in place following the pour?

Also, are you planning on carrying those 3/4" sheets of plywood up onto the roof framing or will you be paying someone else to do it?  If someone else, figure on additional costs for toting that heavy 3/4" plywood up on the roof.

If the soils in your area are suitable, consider using a wood basement. If you are planning on insulating the basement even to r10 it will cost less to use a PWF For less than the cost of the concrete alone you can easily have an r 30 basement with PWF.

The plywood will have a fairly high moisture content after being used as concrete forms folowed by a power-washing, but that's fine as long as you're not going to then seal in that moisture by insulating under the roof deck.

Why not use it as a subfloor?