I'm replacing a floor in a bathroom. I've ripped out everything down to the joists.

Is it okay to: a) screw & glue the subfloor


b) screw the underlayment

Should I use nails? I don't care about speed as it is a small space. I just want to avoid squeaks and problems

  • I did two layers of subfloor. Bottom layer was glued and screwed to joists and top layer was just screwed to bottom layer. For underlayment, I thinsetted ditra to the wood Jan 14, 2017 at 21:38

1 Answer 1


Yes, do both. To avoid squeaks, use screws (not nails) everywhere for the flooring.

I had a very squeaky kitchen and entry-way floor, which I wanted to tile over. I kept the existing plywood subfloor but screwed it down to the joists using drywall screws. I used a LOT of them, one every 4 inches or so along every floor joist, and it eliminated all of the squeaks.

Then we put down Hardibacker-type cement board and screwed it to the subfloor. We didn't worry about screwing the cement board to the joists; just screwed it to the subfloor.

That was two years ago. No tile has cracked or shifted, and no squeaks have returned. Definitely use screws and not nails.

  • You should NEVER EVER use drywall screws for this purpose, flooring screws only
    – justino
    May 9, 2021 at 14:26

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