leveling the pool

[pwa2003]

Hello- I hope this is the appropriate place for this topic:
Our gunite pool was started in March, 2022, plastered & filled with water in September, 2022. Concrete deck was poured August, 2022. Pool was "Loop-Loc" covered in November, 2022... Over the 2022/2023 winter (Tulsa, OK), our concrete deck "heaved" or the pool sunk in the deep end-- about 5/8"-- in one corner only (see photos). I was sure the deck had heaved, since underneath our pool in the deep end is solid limestone, but some contractors that have come to look suspect the pool had sunk. We have no plaster cracks or displaced waterline tiles. Other locations of the pool are slightly heaved too... but no more than 3/16", and I can hold my nose & live with that.

I've invited foundation "lifting" companies over to see about trying to lift the outer perimeter and hope the inner perimeter goes back down (teeter-totter affect), and also concrete contractors to remove & replace the heaved section. I'm getting various opinions. Our Pool GC was an absolute LEMON, and although they're ultimately responsible, our attorney said it may be fruitless to pursue them. We're on our own.

Before I pay for a "fix", I want a accurate assessment of the condition and determine what needs to be fixed. I saw the legacy posts about piers under the pool, but that won't help me because of the limestone bed.

Does this community know of a service discipline that I should look for to take accurate laser measurements? I have an old 1970's Transit, but no tripod or scale, and I don't know that it'll get me to the nearest micron of level to determine if the pool sunk or the concrete heaved.

Thanks.

 

[JJ_Tex]

Does your water line hit the same spot on the tile all the way around the pool? If so I would assume the pool did not sink. If the waterline is higher/lower on one end of the pool then you may have a problem with the pool shell itself.

 

[pwa2003]

Thanks, good point! I think it's even, but I'll definitely double-check just to make sure.

 

[bmoreswim]

All else being equal the most likely reason is the most straightforward one. From the first picture it looks like water could/would flow towards the deck. Is that the correct interpretation of the ground slope? Thereby saturating the soil underneath of the decking making it more susceptible to frost heaving. Mind you, limestone is a soft rock and prone to collapsing when water tables are drastically lowered or other odd reasons, but again, back to the first sentence. Even if the ground doesn't slope towards the deck, natural ground moisture easily causes decks/sidewalks to heave. Many times its not noticeable because they aren't adjacent to immovable objects. Our brick patio, on 8" of base material, heaves about an inch in the winter. It's really obvious when piles of snow keep certain areas frozen longer others and the settling doesn't occur at the smae time everywhere.

 

[AQUA~HOLICS]

I have yet to see a pool move up to a 1/2” without showing any signs of damage to the inside of the finish. Also that 1/2” of movement in the pool shell if it were teetering would be very noticeable on the tile line with water against it.

 

[pwa2003]

Thank you ALL-- These are all really good points. Our waterline tile has a grout joint in the middle that we use as a index for the auto-fill shutoff level... and, although I'll need a less windy day to be 100% sure, it looks like the water level hugs that grout joint all the way around. Our lot slopes from side-to side and from front-to-back. the photo 1 slope definitely slopes away from the pool... There is a side (not shown in the photos) that slopes toward the pool, so the overall concern is valid. I asked them to cave in a low "channel" or mini-swale away from the deck and slope back up to it. It's barely good enough so I might have another 10 yards of topsoil brought in to increase the grade. ... I still think it's the concrete deck that's heaving.