Inground pool coping separating, lifting from pool

[Derekb]

Our pool is probably 30-50 years old. We redid it around 2008. Yes, we had all the troubles and confusions with the pool company. My favorite was, as they were plastering it, I asked, "When do you add the color?" We had paid a good bit more for some kind of quartz/colored surface. They looked very surprised and had to stop, then go to a supply house to get the correct finishing product.
Now, 12 years later, although stating several years ago, the pool edge coping is lifting from the pool. There is a 1/8' to nearly 1/2" gap in the shallow end corners between the pool walls and the deck coping. I will try to take pics tomorrow.
I don't think the pool is sinking. It has been there a long time. When the not very good pool company was redoing it, they commented that the pool was very solid, and they went through two blades cutting into it to install the new double main drain.
My feeling is the coping was not done correctly. Is there ever an expansion/contraction joint in it? Ours is mortared all the way around the perimeter of the pool.
I feel like I should cut a few spots of the mortar, between the coping pieces, and replace that with some kind of expansion joint(s).
Again, I will take pics tomorrow. I have been meaning to ask here for a while and only this year see I really have to do something soon.

 

[ajw22]

Waiting to see the pics.

 

[carlos31820]

I had a section of pool deck that was raising from the pool. What was really happening was that the back of the pool deck was settling/sinking and lifting the opposite end. I ended up having a foundation repair company come and they fixed it. It's perfectly level now.

 

[Derekb]

Hmm, hope this works. There is one pic standing outside the pool looking at the corner with the steps. Then three pics standing inside the pool with close ups of the coping separating from the pool..
Sorry first time posting pics here.

 

[Rossterman]

If the soil is clay and water is getting underneath, the patio may be lifting due to clay expansion. Is the pool waterline tile perfectly level going Around the sides?

 

[Derekb]

Thank you Rossterman. I did just check the tile/water line. They are basically perfectly level.
You may be right about the soil. I just planted a tree in the front yard and noticed our soil is quite clayey.
The patio was done by landscapers, they seemed good but perhaps the base layer the pavers were laid on is not sufficient or correct.
But it is really only the coping around the perimeter of the pool that is lifting, not the pavers adjacent to the coping. It does seem the joint on the surface of the patio was never very good between the coping and first adjacent row of pavers. Perhaps water is getting in there then frost heaving over the winter?

 

[mattw221]

I think moisture is getting under the coping and popping them over the winter. Do you use a solid pool cover during the winter that sits on top of the water?

The good news is it looks like a clean break. If you knock on the tiles in that area do they sound hollow? Any cracking in the grout lines? If not your bond beam may still
be intact and the coping may just need to be reset in a new mortar bed.

 

[Stoopalini]

Is that a large tree right behind the decking? Could the root structure be pushing the coping and decking up? Maybe it doesn't show in the decking as much due to it looking like it's dry fit, but the coping is mortar'ed into place.

 

[Derekb]

Matt221, the tiles do not sound hollow. A few have deteriorated and cracked, mostly the top row and I would say less than 10%. We use a mesh cover.
Stoopalini, those are logs from a neighbor's tree waiting to be split into firewood. No roots!
Thanks all for the help.

 

[mattw221]

It's a shame when they installed the pavers they didn't put an expansion joint between the coping and pavers. I can't say 100% that caused the problem but if theirs any movement in the pavers
it doesn't have anywhere to go. The good news is if the tiles are in good shape those bricks can be reset in a new mortar bed without having to drain the pool or extensive work. They should of used
a backer rod like below to allow some movement in the pavers to the coping.