Mud leaking into pool at top seam between pool shell and deck

[PhantomF]

We had our in ground pool built in beginning of 2017 and was great for a couple years. Then in rain season of 2019 I started to notice mud seeping through in a couple spots between the pool shell and the deck seams. I talked to the builder and he said it happens sometimes because there's no way to seal that gap completely between shell and deck and when the water level is high from rain it will start pushing mud through. He sent a guy out that blasted some high pressure water in the gap to clear it out but seems to only be worse since then and coming out in more areas now. I haven't seen anyone complain about this same issue on this site before so don't think it's very common. Anyone heard of this or know what really causes it? Did the builder screw up and do something wrong? I can't believe this would be an acceptable thing for anyone. I have to go clear the mud after every time it rains or I end up with globs of mud in the pool bottom. Very frustrating to say the least.

 

[ajw22]

You need to put in some dry wells around the pool to pump out ground water from around the pool. This is often done around vinyl liner pools to keep the liner from floating and around fiberglass pools. It is less often done around gunite pools.

 

[Jimrahbe]

F,

If this is a gunite pool, then it sounds to me like the coping has come loose from the bond beam.. It seems to me that water should be moving away from the pool and not toward the pool.

I am not a construction expert, but it does not sound right to me.. I have an old pool that we had to redo for a similar reason.. We had to remove the coping, and fix the bond beam.. At the time we had new coping and tile installed..

Let's see what a couple of our construction experts have to say.. Calling @bdavis466 ... and @jimmythegreek

Thanks,

Jim R.

 

[ajw22]

I suspect @PhantomF has cantilevered coping which leaves a gap...

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

 

[Jimrahbe]

Allen,

Could well be, not something I am too familiar with.. ☹

I guess I could have looked at his pic of the coping..

Thanks for the pic,

Jim R.

 

[PhantomF]

Thanks for the information. I attached some pics from the construction to see if that sheds any light on the issue.

 

[ajw22]

That coping looks cantilevered. Water is coming up the ground under the deck and seeing down the expansion joint.

 

[UKjames]

Could you fill the gap with a bathroom silicone?

I hasten to add I have no experience of this but have a similar problem where there is a gap between my liner and tiles that the ants seem to use to build nests in. And have wondered about using Silicone as a solution.

 

[Jimrahbe]

Seems to me for water to be that high it would have to be bubbling out of the ground all over..????

Jim R.

 

[ajw22]

Seems to me for water to be that high it would have to be bubbling out of the ground all over..????

Jim R.

Water can be flowing from oustside the deck area in channels between the concrete and the dirt. It doesn't need to bubble up. Water flows in strange ways and it could be surface water finding its way under the concrete to the pool.

 

[Jimrahbe]

Allen,

I can't argue with anything you have said.. It just sounds very odd.. If this were a normal occurrence, you would think they would put in a drain or something??? Why would anyone build a pool that allowed ground water to flow back into the pool??

It just seems to me that something was not done correctly for this problem to exist. But, as I said above, I don't know squat about this type of coping.. ☹

Thanks,

Jim R.

 

[PhantomF]

Could you fill the gap with a bathroom silicone?

I hasten to add I have no experience of this but have a similar problem where there is a gap between my liner and tiles that the ants seem to use to build nests in. And have wondered about using Silicone as a solution.

I may try doing something like that after the rain season ends this year.

 

[ajw22]

It just seems to me that something was not done correctly for this problem to exist. But, as I said above, I don't know squat about this type of coping.. ☹

Jim, I don't know how much you can hold the builder responsible for properly analyzing the ground water situation of a pool build. There is a lot we don't know about the conditions of the property at the time the builder planned it.

I would think the builder should work with the owner to get the proper ground water remediation in place now that the problem is discovered.

Siliconing the gap is not going to be a long term fix. The silicone will divert the water someplace else that may casuse other pool damage. The proper fix is to drain and divert the water that is getting under the deck and into the pool.

 

[Rich D]

Can you post some more pics showing all the way around the pool to get a better idea of the surroundings. Also point out at what locations the mud is seeping in. I do not think this is a high water table issue. The water table should be very close to the level of that drainage swale. This seems more like water running off the deck going down the side of deck and back under the cement because it is a easier place to go than through the clay surrounding the deck. It is important to identify where all the surface water is going around the deck. Do you know if and where that strip drain is daylighted? Does that strip drain get overwhelmed during a storm event? Where does all your roof water go? Could you also post some pics of any gutter roof drains you have. If they go into a pipe then do you know where that pipe goes and can you verify that during a Storm it is not backing up and coming out of the pipe? It sounds like you will need a French Drain installed below the bottom of the deck level that daylights out towards that drainage swale.

 

[Rich D]

If you are looking for instant relief you could dig a small ditch in your lawn from just below the bottom of your deck out to the slope going to the drainage swale. The bottom of the ditch just needs to have a very little pitch on it (just cracking the bubble of the level). That should relieve most of the water pressure under the deck.

 

[Rich D]

Any pictures you could post of the pool excavation would be helpful as well. Because this issue took some time to appear it could also be from settling under the pool deck inviting water there as well. The most likely suspect would be the plumbing trench going towards the pool equipment.

 

[jimmythegreek]

Looks like grading issues around the pool deck are leaving water the easiest path ending up at the coping seam. This needs to be addressed asap. Erosion under the deck will lead to major problems. Rich's idea is good, a French drain to the swale should work well. and be cheap and easy

 

[PhantomF]

Sorry for the delayed response here.

Can you post some more pics showing all the way around the pool to get a better idea of the surroundings. Also point out at what locations the mud is seeping in. I do not think this is a high water table issue. The water table should be very close to the level of that drainage swale. This seems more like water running off the deck going down the side of deck and back under the cement because it is a easier place to go than through the clay surrounding the deck. It is important to identify where all the surface water is going around the deck. Do you know if and where that strip drain is daylighted? Does that strip drain get overwhelmed during a storm event? Where does all your roof water go? Could you also post some pics of any gutter roof drains you have. If they go into a pipe then do you know where that pipe goes and can you verify that during a Storm it is not backing up and coming out of the pipe? It sounds like you will need a French Drain installed below the bottom of the deck level that daylights out towards that drainage swale.

I've attached some more pics to this post with an arrow showing locations mud is seeping in. I also attached a pic of the deck strip drain. It does exit and drain at both sides of the cage closest to the house and it does get overwhelmed with water whenever we get heavy rain. The roof gutter drain from the house goes to the same location you can see in the pic. Maybe just need some kind of drain to channel all that water to the pond in front of the pool cage?

Any pictures you could post of the pool excavation would be helpful as well. Because this issue took some time to appear it could also be from settling under the pool deck inviting water there as well. The most likely suspect would be the plumbing trench going towards the pool equipment.

I already posted all the pics I have of the construction earlier in the thread.

Looks like grading issues around the pool deck are leaving water the easiest path ending up at the coping seam. This needs to be addressed asap. Erosion under the deck will lead to major problems. Rich's idea is good, a French drain to the swale should work well. and be cheap and easy

Yeah it's definitely pretty scary to think soil could be eroding away under the deck and eventually it could just start breaking up.

 

[Rich D]

Maybe just need some kind of drain to channel all that water to the pond in front of the pool cage?

That would be the absolute bare minimum you would want to do. In your construction pics you can clearly see the clay piled up on the outside of the forms as well as a depression in the area you marked as where the mud is coming in. So any water that gets under the deck can not get out to the lawn area and is forced out of the deck seam.

It appears they just have a pop up drain for the strip drain. That is not the correct. The best solution would be to put both the strip drain and the gutter drain into a 4" sdr pipe and run that down close to the pond and have it come out to daylight. That should be done on both sides of rhe strip drain.

You should also relieve the pressure under the deck. A French Drain would be the best way to do this. It should go on all 3 sides of the deck and be installed below the bottom of the deck and have stone going up to just below the top of the deck and be tied into the new drain going down to the pond.

 

[PhantomF]

That would be the absolute bare minimum you would want to do. In your construction pics you can clearly see the clay piled up on the outside of the forms as well as a depression in the area you marked as where the mud is coming in. So any water that gets under the deck can not get out to the lawn area and is forced out of the deck seam.

It appears they just have a pop up drain for the strip drain. That is not the correct. The best solution would be to put both the strip drain and the gutter drain into a 4" sdr pipe and run that down close to the pond and have it come out to daylight. That should be done on both sides of rhe strip drain.

You should also relieve the pressure under the deck. A French Drain would be the best way to do this. It should go on all 3 sides of the deck and be installed below the bottom of the deck and have stone going up to just below the top of the deck and be tied into the new drain going down to the pond.

Thanks! I'm going to start by looking into getting drains for both sides for the strip drain and the gutter and see if it stops the mud intrusion. The french drains under the deck sounds like a big expensive project so I would only do that if absolutely necessary.