I have a basement floor in an old house - circa 1950's. I have to cut open the floor to move some plumbing around for a new bathroom and I'm researching different methods / techniques to use when pouring the new floor (I'll be laying down ceramic tile eventually). My current plan is as follows:
1) Lay down a layer of gravel over the existing tampered excavated area. 2) Lay down a polystrene foam insulation. 3) Pour concrete with a rebar mesh to re-inforce (I'll also need to paint a bonding agent down on the old concrete floor edges to ensure the new floor bonds to the old).Is some of this overkill ? Although the rest of the concrete slab is still the original - is there any side-effect of using the foam insulation on only a portion of the floor ? Or is it useless unless it spans the entire area of the houses concrete slab ?
thanks in advance for any answers.