An all-too-common problem with pools is tiles that are loose or falling off. People often ask, “How much would it cost to put these tiles back on?” Well, sticking tile back on is pretty cheap, but it doesn’t address the underlying problem. They’ll just keep coming off.
The problem isn’t with the tile. The problem is with the expansion joint, which is supposed to isolate the pool from the deck. If this expansion joint is missing or isn’t done properly, the usual result is dislodged tile.
Here’s what’s happening: As the deck heats up, it expands. Mainly laterally. As it expands, it starts pushing on the back of the coping (brick, flagstone, cast concrete, whatever). Since the force of the deck expansion is much greater than the strength of the bond between coping and bond beam, the coping is dislodged and pushed out toward the pool. Often it takes the underlying mortar bed with it. The result is that the top inch or so of tile is dislodged.

I’ve seen this occur when the deck is laid between the house and the pool. It’s fairly common, and is easy to understand why this happening: the deck’s got to expand, and it sure as heck isn’t going to move the house foundation much. So the pool’s got to give. But, on the other extreme, I’ve witnessed three-foot wide sidewalks that have knocked tiles off, too. It seems as if the sidewalk would just expand into the grass behind it and leave the pool alone. But let’s not try to out-think expanding concrete. Let’s try to remedy the situation so that we don’t have to worry about what the concrete will do.
An expansion joint between the coping and the concrete will take care of this problem, no matter what the darn deck decides to do.
But it must be done the right way. And often it isn’t. (But that’s OK … I’ll put my kids through college by fixing pools where things weren’t done the right way.) For the inside info on how to construct this little detail properly, read on.
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