Porcelain on wood subfloor questions
Hi. I'm a newie here. I'm wanting to install porcelain tiles and want to make sure my floor can support it. Any guidance would be greatly appreciated.
My floor has 2x10 joints spaced 16" that span 13'8" each way from a center steel I-beam. The subfloor has a stamp I can barely read, but I can make out the following.
Rated Sturd-I-Floor, 20oc, 19/32" Exposure 1.
The website for HardieBacker says the subfloor needs to be 23/32 OSB and engineered not to exceed the L/360 deflection criteria. I saw some posts that said sturd-i-floor is better than OSB, but it looks like OSB. I don't know how to evaluate the deflection criteria.
1) Will my floor support porcelain tile?
2) Do I need to add to the subfloor before installing 1/4" hardiebacker, and if so, what should I consider?
I do notice a few weak spots and squeaking on the existing floor (luan plus two layers of vinyl tile). It might be the luan that is squeaking.