Best Practices to Prevent Water Intrusion

There always seem to be a discussion on here about proper coverage behind tile and why the TCNA specs at least 95%. Water intrusion is one the key reasons. Over time water will work it’s way into the hollow spots or grooves and slowly work on emulsifying the remaining thin set that is behind the tile which brings out efflorescence and will eventually make the tile fail and come off.

When you apply the dotting method or leave grooves behind the tile from the trowel it allows water behind the tile. As you can see in some of the pictures presented here the large format tile fell off one day because of a combination of dotting and leaving grooves.

In the picture of the blue translucent glass tile you can see the grooves behind the tile and there is now mold growing in the grooves.

This pool had many other issues which I will post later about. If you back butter the tile and then knock down the grooves that the tile trowel makes this will ensure you have the proper coverage and it doesn’t allow water in those channels. This is especially important in translucent glass.

When you install the tile thin set should be squeezing out of the joints and you will spend time cleaning the joints out. It is typical that I will use twice as much thin set on a project than what the coverage rate says on the bag.