Protecting it from moisture is a different issue entirely. Tile set outside has always been set on a mortar or concrete because they both move at the same rate. Wood and tile also move at different rate with changes in temperature so the hot sun on the tile will have a similar effect as will the expansive effect of the moisture in the plywood freezing. Plywood is a sponge and moves well beyond thinset's tolerences for movement with seasonal changes in moisture. thinset has a range of movement it will tolerate before failing. Ryan, could I just cover the frame with plywood, then silicone the tiles on, or do I need the cement board?Ĭ What you are working against is movement. You can save a lot by just going to a tile store and ordering it there. The theory behind all this: The plywood is there for support, the CBU is there to bond the tile substrate to the plywood, and the ditra is there as an uncoupling membrane as all the materials will expand and contract at different rates with the weather.ĭitra and Kerdi are not cheap, especially when most stores sell it by the roll. This is why you don't need the pressure treated plywood, but I would still use it just in case. It will keep the edges sealed so no water will enter under the plywood or CBU ruining your setup.

The edges around the kitchen area must be wrapped with another Shluter product called Kerdi. (Durock is cheaper) Cover all this with Ditra following their instructions. On top of the plywood use 1/2' CBU (cement board) either durock or wonderboard. Not sure this applies to outdoor counter tops, but I somewhat think some of the principles are the same.įrame the area to receive tile within acceptable deflection rates, cover with either 3/4' pressure treated plywood or regular plywood, it does not matter.

My idea was for a tiled floor in the barbecue/kitchen area of a deck. From info I received a few years ago inquiring along a similar use.

Tile bartop