Porcelain tile substrate

[Eggman73]

There seems to be a lot of disagreement as to whether you can put porcelain tiles directly on exterior grade plywood. I've had product manufacturer representatives say YES, with the right thinset, and I've had installers say both yes and no, with more saying no. Is there a correct answer? Are the representatives just trying to sell a product?

 

[Mark Brown]

You 200% can install on plywood. The reason you are getting so much conflict is from marketing.... but not from where you think. people waste millions of dollars every year installing unneeded products on plywood to install tile.

 

[C.J.]

Makes you wonder how the heck tile stuck before they invented backer board.

 

[Mark Brown]

Isn't that the truth. While I will not discount the use of all the fancy nonsense on the market right now, there isn't as much a need for it as the marketing would leave you to believe.

 

[Eggman73]

You 200% can install on plywood. The reason you are getting so much conflict is from marketing.... but not from where you think. people waste millions of dollars every year installing unneeded products on plywood to install tile.

Thank you. I'm hoping this all comes out well in the end. So far, the prep work has been overwhelming. I'm still working on making the current subfloor flat and level before adding another layer of 3/4" plywood.

 

[Mark Brown]

See, that is the key. I haven't pulled out the TCNA guidelines in a while, but I think for 16 o.c. joists the min is 1.25" of ply... maybe 1.5? We install tile all the time on plywood, I have made it my personal crusade to eliminate underlayment products everywhere I can as I see them as frivolous and give people a false sense of security. Pfff... I can install on this 23/32 osb... I have Ditra. I just build systems to work and last. That has served me well all these years. Just last night I laid some porcelain tile on 1.25" of plywood in my own house and then plunked my fireplace on it. I'll let you know in 20 years if it was OK