waterproofing before tile
I am redoing my front porch.
It is approx. 8ft by 3ft.
I have put down 3/4in ply. with joists spaced at 14in, the short way.
I want to put down tile, what is my best way to waterproof the ply. before I lay the tile?
I have thought of using a membrane type of product.
Does what you lay have to have some roughness for the mortar to take.
Some other points to consider
Are you tiling in a protected area. Will the entire tile assembly receive rain? Are you tiling with a dark stone or slate?
Do you know what efflorescence is? http://www.youtube.com/watch?v=1Zn2g9sWvsQ
A solid sub floor pre waterproofing is 1 1/4" thick. If the tile install is dark in colour I would use speed setting mortars that don't produce efflorescence. I'd use the special mortar either way to be honest. A product available here in Canada is made by Mapei called Grani Rapid.
When are you tiling. What are the overnight lows. Can you heat the place.
The list goes on and on. For tile specifics JB's site is the best. You need plumbing help there is a crazy amount of knowledge in these pages.
Many posters on JB site disagree with my use of Grani Rapid for the exterior work. It cost 3-4 times the price of regular thinset and for the most part not required by code to use. That said work out the extra cost of this premium setting material vs regular product. Ask yourself is it worth it to keep your grout and stone looking good year after year or if you want to risk efflorescence and the extra yearly work that comes with fighting this off.