Use a squeak barrier---roofing felt(15 or 30 pound) or rosin paper over the plywood and install the flooring---that 1/32" is not a worry.

jbnimble:

What is your floor joist spacing, span, and depth? Are your joists natural lumber or TJI's?

I wouldn't worry about the 1/32nd anyway.

This post was edited by Trebruchet on Mon, May 5, 14 at 20:15

Spacing as pointed out above is crucial. But in any case, the 19/32" is not recommended, according to the Hardwood Flooring Association and the Structural Board Association's OSB Guide. Instead, they call for a minimum 23/32" OSB OR 3/4" plywood.

I would beef up the subfloor with at least another 1/2" OSB or ply. Lots of screws and glue.

(Assuming you're not into quick flipping a la HTV.)

Thanks for the replies.

House built in 1979. I am the original owner.

Joists are true 1 1/2" by 9" (presumably nominal 2" x 10") natural lumber

Joist Spacing 16"

Joist Span 26' with steel I-Beam, making the longest open span 12' or 14'.

Joists are Crossbraced
some 2" x 4" X-Shaped (builder)
many 1 1/2" x 9" x 14 1/2" full rectangles (added by me)

I suspected I needed another 1/4" plywood.
Sounds like the best bet is another 1/2" plywood,
which will raise the floor LOTS after including the depth of the new hardwood itself.

Lowes sells floating, interlocking, true, full-depth hardwood.
I presume it needs no additional plywood.
Does anyone have experience with this?

Assuming the sub flooring is structurally adequate, the important issue is nail holding in 5/8" plywood. 3/4" plywood would have been better but I doubt adding a thin layer of plywood would improve the nailing. A good floor installer will know how to install the flooring properly.