Do you have a cantilever concrete deck (one where the concrete extends out over the water slightly; in other words, no coping) or a regular coping pool (i.e., brick, stone, etc.) with an expansion joint and concrete behind it?

If it is cantilever concrete, what is likely happening is the deck is expanding, pushing out over the pool more. If the pool bond beam isn't level, if it slopes up toward the pool, then as the deck expands, it also rides up, leaving a gap between tile and bottom of deck. Tiles can often be cracked, too, since a properly built cantilever is kind of hard to do.

On the other hand, if it's a pool with coping, a lifting deck is usually caused by expansive soil becoming saturated, pushing the deck upward. Cracked tiles in a situation like this would be caused by an improperly built expansion joint, which is supposed to protect the pool's coping and tile from expansion of the deck.

Hard to say how serious it is without seeing the pool, but, unfortunately, is not all that uncommon. I remodel a pool or two a year with this type of problem. Talk with your builder about causes and remedies.

Sorry this is kind of a rambling explanation, but I hope it helps.

Here is a link that might be useful: poolnerd.com -- free pool construction/design info

Hi Poolnerd,

I am having a pool deck installed this coming week. so far the contractor has removed the old material, dug 4", and put rebar. I thought there had to be gravel put down first, compacted, then rebar followed by pouring of the concrete.
is this correct? is my contractor attempting to take a short cut. what is the minimum for gravel and does it need to be compacted with a machine or can they use a hand held compactor? I am meeting with them this Saturday to go over the scope of work again and I want to make sure they are doing this correctly.
thanks in advance,

~jv