Floating Liner - Water seeping over top edge of pool wall behind liner

[bgood]

I have read almost every floating liner post there is. I feel like most solutions don't apply to my situation. Under heavy rains water seems to pour in under the deck into some kind of void and then trickle over top edge of the wall between wall and liner. This is an inground pool. I drew a little diagram to explain. This problem developed over time. I don't know why the void now and it's only recently causing the problem. Pool is about 7 years old. Water will trickle over top of wall and start a bubble in the 3ft end above the water line and the bubble and water will make its way around the entire pool wall. Under severe rains it makes it's way down to the floor area. Since my source of water is coming from surface water, I don't think a sump pit would work. Also I have clay soil so that doesn't help. I was considering something like the nu-flo drainage system but I don't know that that product is made anymore. The other solution I though to do was french drains around the edge of pool deck to capture the water and release it elsewhere so it doesn't get a chance to pool up under the deck and make it's way over top of the wall.

 

[kimkats]

Is there a void where the grass meets the decking? Is it extra soft there?

I worry you might have to find a way to fill the area UNDER the deck then add something to keep water from getting under there again

 

[bgood]

The previous owner installed a single layer of stones to edge the decking. Water seems to pool here as they are almost in a 2-3" trench on edge of pool deck. Soil layer is about flush with bottome of concrete due to this. i have often though this might be the cause. The edging rocks almost create a type of void around the edge of recessed dirt. I have some pics I can post but don't have them with me at the minute. The reasons I think there is a void is because when I replaced my liner this summer and "knocked" on the wall panels there were several places on the top edge of the walls that sounded "hollow". Also when I had my liner out doing floor repairs, I noticed a small trickle of leaking water hose would pool up at edge of duck and and begin to pour out and seep up under the steps.

It's really strange because there is only about a 2ft grade down to the front side of my pool and the other 3 sides have slopes that go away from the pool. The water always starts to come in behind the liner on one of the shallow corners where contractor had to build a levee. I say levee because there are 2 slopes on this corner with only about about 2-3ft of level ground before slopes begin.

I was willing to do a french drain on front edge of decking where the 2ft grade is in hopes it would catch and carry away water before it could get under decking . Should I remove the rock and fill with couple inches of dirt. I also edge around the 4in decking. Could I be adding to the problem? This picture and one in signature may explain a little better.

 

[borjis]

I had an area at my old house where water would pool up whenever it rained on part of the walkway
heading to the front door. I dug a 2 ft deep trench next to the walkway and filled it in with gravel
to french drain it. It worked very well and never pooled up again.

I'd suggest something like that in the areas where the water pools near the lamp posts.

As to the water bulging your liner on the other side...not sure how that could be solved,
but there has to be some way to fix that. If a 4 feet dry well was installed near the lamp posts
instead of a french drain I wonder if that would do the trick?

Your situation is definitely a different one, but this sounds like a water table issue at it's core.
If a sump pump keeps the water level, lower than your shallow end, it should take care of it.
I would think.

 

[jimmythegreek]

the water most likely isnt going over the top of the wall, its getting thru the seams of the walls. If you had a large void(s) under the deck and the water travels under the concrete it may get behind the coping track but the concrete is usually thicker than just the coping face.

if the water bulging is just in this area and its on the sidewalls not the deeper end it may very well be surface water. looks like you have enough pitch in the ground to get a french drain in around the area. A simple fix would be to dig a trench as deep as possible around the edge we can see in ur pic posted leaving enough pitch for the piping to come out down that slope somewhere and drain naturally. I would line the trench (12"wide is plenty) with quality filter fabric install hard pipe NOT perforated flexible stuff and pipe it with necessary 45/90 degree fittings and T both sides in the upper left corner and drain it a ways out to daylight. You want clean 3/4 gravel in the whole trench and you want the fabric folded over and sealed up well, I use filter fabric meant for septic tank installs, local supplier has it on 12.5' rolls for 1 dollar a foot very heavy duty stuff. after you bring gravel up close to grade top it off with river rock or decorative gravel and make a "bed edge" like a landscaping bed of mulch but with gravel. You could top it with dirt and grass it or plant it with mulch but it will drain best with gravel through out. Id be curious if you had access to an auger if you drilled a hole or two by stairs side and opposite side how the earth would look 3 ft deep. You may be surprised to see water sitting there. I have clay soil too and am not done backfilling and prepping for pavers/walls on my site, and I have 2 veins of water that run forever after a rain, one spot takes 2 weeks of dry weather to dry up fully and stays damp in the area for no reason

 

[mclifford]

What is that pipe for that is sticking up to the left of the side walk?

 

[bgood]

The pipe sticking up is to septic treatment system. One of the pipes you put cholorine tablets in and the "clean" water drains underground and comes out at bottom of the hill.

I was leaning towards French drains and add sump if that doesn't take care of it I think you are right that it's coming in through seams. There is nothing but duct tape between groundwater and that seam. It bulges on that far corner first and then rolls around the entire pool in the void between liner and water surface.

 

[mclifford]

I see you posted a thread about replacing your liner. Did you notice any water seeping through the pool bottom while you had the liner out working on the bottom?

Replacing your own pool liner is possible - My journey and how I did it

 

[bgood]

Well yes and no...not immediately, but I had a small leak in water hose and when the water would pool up near the sidewalk after about 30 minutes I noticed it pouring out from under the steps. There was even a small tunnel where water was coming up next to the steps. This was surface water making it's way down like it had a straight path to bottom of steps.

I was going to post a picture of buldging liner, but by the time I got home the water receded and liner stretched back into place. This all happened within 12hrs. Liner was buldging by lunch after 6-8" of rain (Thanks Gordon) and by 6pm when I went home to pump out water, it was gone. I had a lot of floor damage around the edges (especially shallow end) when I recently replaced liner. Does this indicate what kind of water problem I have?

 

[Rich D]

It certainly sounds like a surface water issue.
Unfortunately it looks like poor planning from the start. A slope like that heading for the pool deck was a bad idea. Constant water pooling will force any improperly compacted areas to settle over time. There should have been a drain to start with or swale.

I agree with the French drain idea, with a few changes. I would suggest filter fabric only on bottom and sides of trench and stone all the way to top. 3/4 inch stone for drain and decorative stone on top. Surface (storm) water can come in far to great of volumes to be able to seep through filter fabric. Just be sure to place 4" of stone under the 4" pipe. This will allow any fines the get in the drain a place to settle. You should use a 4" smooth wall perforated pipe. Do this around the entire perimeter of the pool. The trench from the perimeter of pool to where it will daylight can be solid and buried, be sure to keep the same amount of stone in the outfall trench and wrap all sides, top and bottom with filter fabric. Be sure to run the French drain up both sides of the walk as well.

 

[PoolguyinCT]

To echo the above. That pool was built to low.

The photo with the truck says it all..

 

[bgood]

How deep you think drains should be? I was thinking about 16-18". I was also considering sawing a small 12-18" section of sidewalk walkway so I can extend the drains beneath it and then laying the solid piece of concrete decking back over the top. Is that a bad idea?

 

[JohnT]

I think I'd want to go as deep as you can get away with. Just guessing without being there to look, but I'd consider going down at least a couple of feet below the level of the skimmer in the pool. With a trencher, it won't be much more work to go deeper if there is nothing in the way. Drainage pipe in the bottom with a sock on it draining to daylight. Bigger rock over that, then a layer of filter fabric near the surface and some decorative rock over that.

 

[jimmythegreek]

The deeper the more volume u can handle i would grab a mini excavator or even a micro i personally wouldnt use a trencher
My advice is to wrap the whole trench w fabric like a Xmas present. Use a premium fabric from a septic supplier not a soil separation fabric as Rich D stated it will not drain thru fast enough where quality filter fabric drains no problem dont skimp home cheepo stuff will fail i promise. I do this regularly in my line of work and have dug up lots of drainage pipe w socks on it and other ways of piping that failed. In drainage work u protect ur stone that's ur drainage tool the pipe only directs it away.

 

[Rich D]

How deep you think drains should be?

I would start with a minimum of 18". 24" would be better . You will want to put some pitch on it so it will get deeper as you go. These drains do not need much pitch, just enough to keep the water going in the correct direction. I would use .5% = (19/32" in 10ft) for simple math just go a heavy 1/2" per ten ft .

I was thinking about 16-18". I was also considering sawing a small 12-18" section of sidewalk walkway so I can extend the drains beneath it and then laying the solid piece of concrete decking back over the top. Is that a bad idea?

That is a good idea. It would save having to run the drain up the sides of walk and be more effective.

 

[Rich D]

The deeper the more volume u can handle i would grab a mini excavator or even a micro i personally wouldnt use a trencher
My advice is to wrap the whole trench w fabric like a Xmas present. Use a premium fabric from a septic supplier not a soil separation fabric as Rich D stated it will not drain thru fast enough where quality filter fabric drains no problem dont skimp home cheepo stuff will fail i promise. I do this regularly in my line of work and have dug up lots of drainage pipe w socks on it and other ways of piping that failed. In drainage work u protect ur stone that's ur drainage tool the pipe only directs it away.

I agree with all of this except the fabric on top. I have seen this fail in high volumes of water even with a good quality filter fabric. From what I can see in the pictures you will most likely not get that much water so it would most likely not make a difference. You will need to protect the drain either way during and after construction, until the soil is stabilized. Wattles (6" tubes of hay in a roll) are the best but regular hay bales work just fine as well.

The stone does do most all of the work and protecting the sides and bottom is a good idea however without the top layer any silt/ fines that do find there way to the top of the drain will either get trapped in the leading edge of stone or in bottom, (hence the 4" recommendation of stone below pipe). After soil is stabilized there is not much going into drain that will plug it. If you think about it the fabric on top will collect these fines and slow down the water getting into drain. Sure you can always remove top decorative layer and remove/replace fabric but I have never seen this done.

@OP - where is all your roof water going? Do you have gutters?