Most likely the pool is not sinking but your deck could be heaving. If the subgrade was wet or not compacted properly then it can swell in cold weather and push your deck upwards. Since it is very unlikely that your pool would have settled un evenly check your water level on your tile. If it is level all around the pool then then deck moved.

Thanks. Our pool is closed for the winter so we can't see any water. Even if we could, the water is well below the tile line.

Thank you SO much poolcenter.com! My husband and I are nodding in agreement when reading your reply- we think you're spot on.

We have not caulked yet- we still have the foam-like strips between the concrete. At what point next year should this be done?

We've already noticed an improvement so hopefully things will even out.

Again- thanks so much! The picture on your blog is exactly what we've got going on here.

After the Spring's main pollen drop. Some caulks take longer to skin over than others.

Scott

Boy am I glad I read this. It's our first winter with our pool (we're in SE PA) and was out at XMas with the kids and noticed the deck was slightly higher than the coping...about an inch in one spot. Was too worried my pool was sinking. Frost heave makes sense though as we also just have that foam like stuff between the deck and coping. Hopefully in the spring it'll level itself back out or at least get close and then we'll caulk it before next winter.

Thanks.

Teeter tottering is possible. Without pix, we won't know. We do know it's Winter and moist clay expands and when it freezes, gets even bigger.

Settlement near the dig would have caused it to sink near the coping, not rise. Your own pix show this.

Scott

Settlement near the pool would cause it to sink near the pool, settlement away from the pool with relatively less or no settlement in between would cause it to rise at the edge of the pool.

To help ensure that it drops back to its original level if it is just frost heave, you can try putting 60 gallon trash cans full of water on the areas that are lifted the night before a day when temps are predicted to be above freezing.