August 26, 2013 7:26 PM Subscribe
I'm installing cheap laminate flooring (I know, I hate it) over lousy floorboards that I won't replace, and I'd like to get a few years (of sock-footed padding like a cat) out of it. The floorboard plywood sheets are gapped and uneven at the gaps and the builder didn't use spiral or ring-shank nails (but I'm adding screws). Can I just fasten thin plywood subfloor over plywood?
posted by Shane to home & garden (5 answers total) 1 user marked this as a favorite
Due to uneven expansion rates it's always recommended that one surface "float" (unfastened) above another, but I've experimented with screwing down even 7mm plywood to the floorboards and it's a surprisingly durable surface that doesn't buckle even with summer temps ranging from 50s F to 80s in the same week, 50s and 70s in the same day/night. Will one sheet of plywood eventually tear away from the other? It doesn't seem likely, but it's such a DIY sacred cow. I have very little moisture (wafting up from the basement) but plenty of ambient humidity, and I'm rolling down a primer-style vapor barrier (no plastic sheeting, thank you) that lessens the likelihood of humidity between the two layers of plywood. (Thanks.)