Sink Hole At Pool Edge

by T
(Toms River N.J.)

We have a 21' round above ground pool. I noticed an 8" x 6" sink hole along the side of the pool wall. It is about 2" deep.

Should I try to push the sand back in or will that cause it to cave in. What should I do without having to drain the pool?

Hi T

A sink hole in the pool cove area is something to really keep an eye on. Something has to have been the cause of the sink hole and it is usually a hole in the liner. You should be checking for wet spots around the outside of the pool, checking the pool water level and examining the area with goggles.

If you do find a hole it should be patched. This can be done underwater.

It is also possible that the cove washed out under the bottom rail. If this is the case make sure the outside of the pool is well packed with dirt, or other landscaping, to prevent further wash out.

As far as the sink hole itself goes, make sure the liner is not resting on the pool frame. It should not be in contact with the bottom rails or footplates. If it is I would drain the pool ASAP. A tear in the liner at this area of the pool causes major blowouts.

If the sink hole does not have a hole in it, and is not resting on the pool frame, you may want to just keep a close eye on it. If it does not get any worse it's probably OK left as it is. It is very difficult to try to force sand or dirt up into the cove from the outside of the pool, and this could easily further the damage.

If repairs need to be made, be careful not to drain too much water out of the pool. An empty liner will shrink very quickly. Leave a few inches in the bottom to hold the liner in place and keep it from shrinking. It is also a good idea to drain, repair and refill all in the same day.

Sink Hole Repairs Under The Liner

by Brutuss
(West Chester, Ohio)

I know that various companies have unique ways of fixing sinkholes that form under above-ground pool liners, but how do you know what are the best options to choose from?

A couple of the suggestions were as such and I am not sure about some of them. Can you advise on each method listed below?

1)A small cut in the liner at the center of where it is being pulled into the sinkhole and stuffing in plastic bags to fill the gap and patching the hole.

2)A small sand bag the same depth and diameter laid into the sinkhole without cutting the liner and covering it with a large patch (just sort of filling the gap and putting a band-aid over it).

3)Injecting some type of silicone filler under the liner at the sinkhole (but I can't find anyone that does it)

4)Removing the liner, fixing the spot and reinstalling the liner (the water to refill a large pool is expensive and time consuming).

5)Portland concrete injections (but again, I can't find anybody that does it).

What do you suggest?

Hi Brutuss

You need to drain the pool and take care of the sink hole. It is the only way.

Try to leave a little water in the liner, just enough to hold it in place. Someone can pull the liner back while you make the repairs. You fill in the hole, cover it with some sheet metal, add some more sand and smooth it out.

This all needs to be done in a days time. Liners will shrink fast, and become unusable. That is why you need to work fast, leave a little water in the pool, and refill the pool during the hottest part of the day.

Slitting a liner over a sink hole is not a good idea. You have no idea how deep the hole is. There is a lot of water pressure pushing down on that area, given the chance the liner will split wide open.

A pool in my neighborhood was over some type of old septic system. It got a leak one day, moments later the entire pool had emptied into the sink hole. It is lucky no one was in the pool. Knowing this, I would not be the one to go to the bottom of the pool and make the cut into a hole of any kind.

None of the other suggestions made any sense to me either. I would drain the pool.

Sink Hole

by Christine
(Wilmington Ma)

My liner and pool is only one year old, a hose let go and was directed at the base of the pool and created a sink hole directly below the skimmer.

It follows the inside wall about 1 1/2 feet then is about 6 inches towards the middle of the pool and it's about 5-6 inches deep. Can I save the liner?

Hi Christine

The good news is that your pool liner is young and fresh and should have no problem stretching back out after it is drained.

The bad news is that you do need to drain the pool.

Leave an inch or two of water in the pool to hold the liner in place and reduce shrinkage. Once the pool is drained release enough liner so the someone inside the pool can pull it back and out of the way while you do the repairs to the cove.

I find it works best to have someone inside the pool pulling back on the liner while I do the filling in and and smoothing of the cove from outside the pool.

The liner is then put back in place and the pool filled. The key is to do it all ASAP so the pool does not sit empty for any length of time.

Another helpful tip would be to plan it so that the pool is refilling at high noon, and full sunshine. This really helps the liner to stretch back out without having to readjust the whole thing.

What you are experiencing is the reason they invented preformed pool cove. While I would not even consider installing them now, they might be worth considering when you really do need to change your liner.

Pool cove wash outs are a pain, anyway you look at it.

Sink Hole in Liner

by Sandy
(Easton, MD)

I had an above ground pool installed (20 x 40) 4 years ago. The installers put a small hole near the top of the liner. Before they patched the hole it leaked a little and caused a sink hole below it on the bottom. They were not concerned with the sink hole as it was not supposed to be a problem.

Last week I brushed the bottom of the pool and it tore the liner in the sink hole. Was this the installers fault for only patching and not repairing the sink hole?

Hi Sandy

Sink holes can always be a problem, especially ones that could have been prevented. Yours should have been fixed.

If the sink hole was caused by the installers, like you say, they should have fixed it.

There is no reason you should have been asked to baby this one area, to be very careful when cleaning the pool and when swimming in it. You were asked to tell all the pool users to never stub their toes in the hole. You were asked to clean this area by hand since a brush or a vac should never go near it. That's just not right with a new pool when the problem could have been easily fixed.

Had you put a hole in the liner, and it washed out part of the cove, causing a sink hole, that's different. You then have the choice of being very careful around this area, or draining the pool and fixing it. Then it is your decision, either way you go.

Potholes In Pool

by Linda Eder
(Paris )

Above ground pool two years old has settled. Ground rail is now showing and there is a pothole right beside the rail. The liner is stretched over the rail and dipping in the pothole. How do I go about fixing it?

Hi Linda

Potholes in the cove area are usually caused by a hole in the liner. You need to drain the pool and repair the cove, check the liner for a hole also, if so, patch it. Anytime a liner is in contact with the metal pool framing it is a dangerous situation.