I recently bought a house that is about 80 years old and we are gutting the kitchen. After tearing up a very old and ripped vinyl floor, we discovered that there were several layers underneath -- the vinyl was put down over 1/4 inch plywood, which was over another layer of vinyl and another 1/4" plywood floor.
Underneath that is a solid 3/4-1" thick wooden subfloor. We want to nail down a new solid maple hardwood floor (were thinking of select 2-1//4" wide strips). I previously bought some 1/2" pine plywood thinking that it would help level out some of the problem areas in the existing subfloor if we put that down first -- there is, for example, some serious cupping by the sink area. But now several people have said to just nail the strips down directly on the existing subfloor and don't bother with an additional layer of plywood. What do you think?
There may be a threshold issue going into the dining room -- it is already a hardwood floor, but I'm guessing that even with the vinyl/plywood layers out, the kitchen floor will end up a little higher than the dining room. So I'm not sure if an extra 1/2" on the subfloor will be problematic.
well, if the extra height will not be aproblem, then go for it if it has a use.
but plywood is not the proper leveler for floors. it may help, but still may not be stable enough if your substrate is bad in areas.
how did your project turn out. I just bought a house built in 1942 with almost the exact same issue. Did you end up nailing the strips to the subtrate flooe with no plywood down? I had a flooring guy come over and say the same thing, no plywood needed, just rip out the 1/4 inch play and lay the 4" flooring.