Which Plywood?

Bud Cline

3/8" minimum thickness.

MrRyan001

ok, so ive decide to just lay another layer of exterior grade plywood on top of the non-exterior grade plywood at the thickness you mentioned above. Any suggestions about seams (especially the seam created when I put the exterior grade plywood against the tub. I don't want water going down the wall of the tub onto the first layer of plywood) so water wont get to the second layer of plywood?

Bud Cline

Caulk the plywood to the tub.
Caulk the tile to the tub.
Seal the grout. (For what that's worth!)
Use a shower door or curtain.
Use a bath mat.
Control the kids.
Wash the dog outside.

Bud Cline

Such as - WHAT?

What is wrong with using the plywood recommended by the entire industry as MrRyan001 has decided to do?

skymaster

This may sound crazy but: Since I have to presume the first layer is the first layer on the joists and usually not water resistant, I may just go get a gal or so of waterbased poly and just really have at it, do the GOOD caulk at the tub, then put second layer and caulk again at tub.
at least that will really slow down any absorbtion of moisture in the base layer.

Bud Cline

Yup sure does!

I think the imagined issue is being over analyzed.