Installing Tongue-and-Groove Flooring Over Joists
Michael Kalman| Posted inGeneral Questionson
Is it acceptable to install 3/4” T+G flooring over joists? The joists would have 5.5” open cavity with nothing inside so they would sound hollow, but there would be 5” of spray foam just under the whole joists system, under the 2×6 joists that is insulating the top of the metal pan under the tiny house trailer.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
This is pretty common in older houses. Tends to be very squeaky and bouncy. I've done 2x6 T&G without a subfloor, which is much more solid but still squeaky.
I would stick to standard construction. If you want thin, go for an engineered or laminate floor over proper subfloor.
Do you think 1/2” ply under the 3/4” t+g is better than nothing or should I go back to the original 3/4” I had before the water damage
I would go with 3/4” which is standard. I’d also screw it down (or use scrails), and probably glue too. Squeaky floors are annoying, and this is one of those things that you really want to do right the first time. Nails alone tend to lead to squeaky floors later.
Bill