Solid Hardwood, Engineered and Laminate Flooring - How perfect does plywood subflooring need to be?

I am going to install wood flooring in a 15x18 ft room over plywood subflooring that is a little ragged in a few spots. By ragged I mean that the top ply, in some spots near a wall, is partially missing or torn off. The top ply layer is probably 1/16th inch, and the spots are about one by two feet in size. The floor is still solid in these areas, just not very smooth compared to the rest of the plywood.

I'm open to any solutions but I'd like to avoid taking up this plywood subflooring. How critical is the level and is there a way to even it out in this bad spots? Or is there a different way to handle this?

I haven't decided on the type of wood, but I if I want to match an adjacent bedroom I'll use strips 3 1/4 inches wide.

John

The plywood delaminating suggests that there may be a moisture problem.

I would invest in a pin/probe type moisture meter!! It may cost a few bucks now, but what is it going to cost you if the floor cups and you have to tear it all out, on your dime??


If the moisture checks out to be acceptable, and in the 8-11% range, then fill the low spots with roofing felt. Layered to bring it up to the right height.

Thanks for the ideas. There was no moisture involved, probably someone, along time ago, pulled off some vinyl tile that was glued to this floor and took some of the plywood with it. There was carpet covering the plywood and I didn't notice the problem until the carpet was removed.

John

The same holds true for the high spots too ,you can take a belt sander to the peaks in the plywood seams and knock them down a little.
If there are spots in the ply that is delaminating you can chisel those out if they become too much of a headache to deal with and fill the holes with feather edge or floor patch.
But ,like he says you want to check that moisture first and get that into check before you proceed any further :cool:

It turns out that the delaminating plywood is 1/4 inch. I've pulled off one sheet because I had to fix the subsubflooring below it next to one wall. 1/4 inch sounds very rinky dink, but I'll probably just replace one (possibly two) sheets with more 1/4 inch rather than replacing all the plywood with thicker stuff.

Any opinions about using 1/4 inch luan? It's much cheaper but I'm don't know anything about it, is it an adequate replacement for regular plywood. This is a small, old house that may be sold in a year as a teardown, so I'm just trying to make it livable for a year or two.

John

APA or CDX is the acceptable 'norm' for subflooring.

Any idea what the classification is for 1/4 " luan?