Kitchen Subfloor Thickness

jestjuggle

Hi -

We are redoing our kitchen and found some subfloor that needs to be replaced due to water damage.

The house was built in the early 1960's. The subfloor has two layers. The bottom is 3/4 inch the top is 1/2 inch.

The problem we are having is what to use to replace the damaged part. We have been unable to find anything that is truly 3/4 or 1/2 inches. It looks like what is available now is 23/32 and 15/32. We found a few things at Lowes and Home Depot that claimed they were 3/4, but when we measured them they were nearly an 1/8 inch less.

Has anybody else encountered this problem?

Thanks in advance for any help or suggestions.
Jestjuggle

Bob Mariani

we all have. Simply add the appropriate shim material between the two sheets

jestjuggle

Hi Bob -

Thanks for responding. Any advice on what is a good shim material?

Bob Mariani

Depends on the thickness you are trying to adjust for. Usually lathe material or just run some shims to size from a 2X4 on a table saw. But wood shims embedded in PL400 and tacked down to not move would be what you want to do. Place them between the two sheets of plywood.

Daniel Holzman

Plywood comes in a bewildering variety of sizes. I build a lot of cabinets, and I have encountered nominal 3/4 inch plywood that is 23/32, 3/4, and metric. As a result, I have a collection of router bits sized to fit the plywood.

If you go to a real lumber store, not a big box store, they may very well have actual 1/2 inch underlayment and actual 3/4 inch plywood. They probably also have plywood that is short of the dimensions you want. Bring a good tape or a measuring gage to be sure.

joecaption

If you cut out the sub floor enough to figure out where the joist are you can cut the floor out along side of them, once the hole is cut out you can reset the depth of the cut and cut the underlaymant back at least 2" from the hole, all the way around the hole.
Attach 2 X 4's to the sides of the floor joist so you will have something to attach the new subflooring to and install the 3/4" subfloor. Then cut the 1/2" underlayment. Use floor leveler to fill any gaps.