Concrete pool apron heaving or shifting?

[kbuhagiar]

Hello folks,

Our new-to-us pool is around 22 years old, and had been neglected for a few years - or maybe longer - by the cheapskate previous owner.
It is now fully functional and swim-ready and we have been using it regularly, but there are a few rough spots that we hope to correct, and maybe give us a few more years before we have to do any major work.

He is the first mystery: a section of the concrete apron has shifted upwards by (at the highest point) about 1". (If we lived in the midwest I would swear it looks just like frost heave.) The only trees we have are palm trees, so I don't think roots are the problem. In the picture you can see the deformity in the curved section of concrete just beyond the kiddie pool and it is now sitting above the level of the slate rock bordering the edge of the pool. At first we thought that maybe the pool had settled on that end, but the waterline is dead nuts even at the tile line along the entire circumference of the pool. (You would think that if the pool had settled, the waterline at the settled end should be sitting higher up in the pool at the tile line, right? If not please educate me.)

At this point it's more of a cosmetic annoyance, and hasn't taken one whit of enjoyment factor from the pool, and if this is the worst problem I have to live with I'm a happy camper, but if there is an underlying problem that needs attention I'd like to be aware of it.

Any thoughts on this situation? All opinions are greatly appreciated!

 

[ajw22]

Give us a closer look at this area which I think is the problem area....



@AQUA~HOLICS is in your area and may have local knowledge of the soil conditions.

 

[kbuhagiar]

Give us a closer look at this area which I think is the problem area....



@AQUA~HOLICS is in your area and may have local knowledge of the soil conditions.

I'm away from the house, but here is a closer look at higher resolution...and I think it may be the trees after all. That apron is part of the concrete planter where the three palms are planted, and the planter is at the edge of a slope, and that slope edge may have settled. The palms are all 30 - 35ft tall, and I'm thinking that the force of the tree, and the wind blowing on them, may have leveraged the apron upward.

 

[flynwill]

From the pictures my guess would be that it is the pool structure that has sunk down hill, as there looks like a pretty steep slope behind the pool. Is there any noticeable difference in the where the water is on the tile line from one side of the pool to the other?
On the bright side if it has only moved that much in 22 years it's probably a major issue. (But will require re-doing the deck if you want to correct it.

 

[AQUA~HOLICS]

From the picture provided it appears to me that one of two items or both are occurring.
Expansive soil conditions or roots from the nearby palm trees.
Typically Shotcrete/Gunite pools don’t settle without structural damage occurring.
This may have started with deterioration of the mastic in that area that allowed water to enter between the coping and deck. With expansive soil lifting occurred allowing the break in the deck-o-seal to get progressively wider.
Now that the soil was hydrated the palm trees grew roots towards the moisture and lifted the deck even more.
The soil under the deck has no horizontal movement and can only move vertically between the pool shell and planter footing.
Just my opinion from a single picture.

 

[kbuhagiar]

From the pictures my guess would be that it is the pool structure that has sunk down hill, as there looks like a pretty steep slope behind the pool. Is there any noticeable difference in the where the water is on the tile line from one side of the pool to the other?
On the bright side if it has only moved that much in 22 years it's probably a major issue. (But will require re-doing the deck if you want to correct it.

As I mentioned before, the waterline is dead even around the entire pool. No difference at all from one side to the other.