I'm installing sheet vinyl flooring in the bathroom. Home Depot told me to get this hard plywood, just under 1/4" thick for underlayment. I'm concerned though because my sub floor is 10" or 12" wide boards with a good amount of gaps between them. I was thinking of throwing another sheet of 3/8" OSB on top of the subfloor, then the 1/4" underlayment. Is that a good idea, or bad idea? Really needed? I'm wondering if there will be a problem with the nails going through multiple layers of plywood?


1 Answer 1


The goal is a smooth, flat surface for the vinyl to lay on. If you can do that with 1/4, then that is great. But in your case it sounds like you need to step up to 3/8 or 1/2 depending on the gap. Once you put that down, then there is no need to add 1/4 plywood.

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