Starting the Sandwich Subfloor

The first step in our basement remodel is to fasten the sandwich subfloor to the concrete slab. As you can see in the pictures below we put down 1" of polyisocyanurate foam with aluminum foil on the sides. To prevent any cold or moisture from coming up through this insulation we used Tyvek tape (aka sheathing tape) to seal the seams of the insulation. The following pictures show the foam with taped seams:

Did you see my Dad taking a measurement for the next piece of insulation? He's been a huge help in helping with all of the house remodeling and finishing we have been involved in.

On top of the insulating foam we used 3/4" tongue and groove OSB to finish the floor. Once all of these pieces were in the proper places we used a Hilti DX350 nail gun to secure the sandwich subfloor to the concrete slab using 2.75" nails. The following pictures show the floor fastened with the 3/4" tongue and groove OSB:

The edges of the subfloor are spaced at leat 1/2" from the foundation walls. This allows for expansion. That gap is filled with spray foam so that the entire floor will be insulated. The OSB makes it so the floor is sturdy for some types of flooring like tiling.

Well, almost the whole basement will be done with this subfloor. The storage room will not be to allow for proper drainage of the floor drain.