[Nealtw]

Hi all -

I'm currently in the process of completely gutting & rebuilding a small master bathroom in my home in NJ. The subfloor is completely shot - old plywood has half rotted, mostly delaminated, and clearly needs to be replaced. Never a dull moment!

I ordered a sheet of underlayment from my local lumber yard, and they wound up delivering a sheet of pressure treated ply, stamped ground contact / general use. (I believe it's "Hoover Micro-Guard"). Can anyone tell me if this will be okay to use as a bathroom subfloor in general (i.e. it won't be too wet and warp like crazy, won't corrode fasteners used to secure it to the joists or the fasteners I'll be using to secure cement board to it, etc.)? Also, is it safe for use indoors, and code compliant? There are quite a few conflicting opinions on both of those, making it ridiculously confusing.

Thanks so much!
- EPF

It is not like treated lumber of old and we see much more used in the houses today, not sure about ground contact and it's ingredients but sealed in the floor it would not be exposed. That said I would want to use fasteners that are rated for treated lumber for the high copper content, adding any moisture would cause rapid rust for general use screws.