So I bought my house in 2009, 5 years after my IG pool was installed by the previous owner. When I took ownership of the home, I found the pool's coping on the one side of the deep end was not flush with the pool deck -- it's raised, about 1.5" max in the worst sections. This extends down a good portion of one side of the pool; the other side is just about flush with the pool deck. The raised elements of the pool have pretty much stayed consistent over the past 4 years, though I do think there has been some slight progression in certain sections.
Lately, I've been wondering if this is due to the shell being pushed on by water or expansive soil or if the deck is settling in the sections that are displaying the problem. Is there any way to tell the difference? I want to get a good hold on the cause of the issue, because I was thinking of re-plastering next year. If its a soil or water issue and is destined to get worse, eventually killing the pool, I definitely want to hold off on any major work.