Pool Floor Level - Metal Frame isn't

[avergreen]

First, I'd like to say "Hello!" I have frequented this site a few times recently and it's been a huge help.

As you saw from the post title... I have a concern. I took a loathsome amount of time 4+ weeks to make sure my 20' dia. base (for 18' pool) was perfectly level, smooth, stone-less, and "soft" (Mason Sand under ground cloth/liner) and tamped both the ground AND the sand. Once I was comfortable/satisfied with the leveling (to within 1/4" of inch of variation from side-to-side), I then setup the pool - leveled vertically & laterally the legs checking them constantly while it was filling and let it fill overnight. The next morning the pool was within a foot of full, but I noticed 3 legs had "dropped" about 1 inch during the night. I thought, "I can handle 1 inch" - will drive me nuts aesthetically, but should be structurally sound, so I continued to fill. After about 2-3 days of fully filled I noticed the same legs (and two others) had dropped more wherein the original 3 legs were now nearing 2 inches low - this is a problem. HOWEVER, after hours of depth measurements around the actual pool floor - not the support legs, but the liner floor that the water is sitting on - I discovered the water itself is not out of level 1/8-1/4" of variation from side-to-side. It appears just the 3-4 frame posts/T's are lower than the rest of the frame due to settling.

That long explanation brings me to my question: Should I be concerned with the frame being "uneven" but the actual water weight and base is perfectly level (i.e. not sloping)? The frame structure "seems" strong - it has minor movement (not the legs, the upper horizontal ring) with water shifting during swimming play, but I attribute that to being normal. My yard is higher than either of my neighbors yards, so if something were to give way, then their yards and possessions would be likely "obliterated" from the water rush with gravity enhancement.

Would appreciate any feedback, advice, or musings on this before I attempt to jack the worst of the 3 supports if, for any reason, but piece of mind.

Thanks!!

 

[gwegan]

Some pictures would be good here so we can be sure we are talking about the same thing.

If your pool is level in other words the water is equidistant from the top of the rail all along the pool edge but the vertical supports are not consistent that is probably not good. Before we talk remedies lets see some pictures.

 

[Jamison04]

I'm gathering you did not put any concrete pavers or pressure treated wood under any of the pool legs. Doing that would have prevented the legs from sinking into the ground as the weight would be more evenly distributed across the underlying support block.
Even with pavers under the legs it can still sink if there is a soft subsoil. It happened to mine on several legs and I had to jack up the pool to slide a filler under the sunken supports. So it is not at all uncommon.

 

[Handymam]

Hope it is OK to post this here. Intex Ultra 22 feet . Built a retaining wall to hold dirt, excavated , tamped with a vibrating compactor , sand , foam etc. I was level according to my 2x4 attached to Rebar & level taped . Installed pool legs level and plumb . Dug out oder them for 2 " blocks . Used my own self leveling laser level and stick . I was shocked that I am 3 to 4 plus inches off in some areas . I was thinking of trying to meet in the middle and of course digging down my high areas , but also increasing the depth of my blocks in my low areas . I am concerned that there could be such a big difference between the block and the actual ground that it would cause a failure . Not sure what options I have if any . Luckily only rain water is in my pool .

Sent from my SM-N910T using Tapatalk

 

[avergreen]

I'm gathering you did not put any concrete pavers or pressure treated wood under any of the pool legs. Doing that would have prevented the legs from sinking into the ground as the weight would be more evenly distributed across the underlying support block.
Even with pavers under the legs it can still sink if there is a soft subsoil. It happened to mine on several legs and I had to jack up the pool to slide a filler under the sunken supports. So it is not at all uncommon.

No. I did not place pavers or 2x6 PT wood beneath the legs. My assumption is that these particular 3 legs, all adjacent to each other, are sitting on soil that I apparently did not compact well enough. The remaining 15 legs are rock solid and have not settled more than one would expect with roughly 1.5 tons of uniform distributed load on each of them - they are all still very much on level too. It's been two weeks of heavy swimming since then and those legs have not moved - only these 3 mentioned. It seems I may to need to jack them. I have the tools to do it and I already have the pavers and paver base (crushed rock & dirt) in my garage somewhere, so I think I'll likely need to bite-the-bullet and get it done. Thanks for the feedback.