Draining Fiberglass Pool to Fix Main Drain Leak

Liquid

Silver Supporter
May 11, 2023
24
Jacksonville, FL
Pool Size
4240
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 700
I have a 4,240 gallon San Juan Cyberlane with Spillover Spa (W 8’6” – L 23’ – D 4’9”) pool with a main drain leak which is on the outside of the main drain, as shown in the picture. This leak detection was done by a professional leak detection company. It’s nearly impossible to find someone who wants to work on a fiberglass pool and was only even able to get one company to give a quote for the repair, which was $5,500. My wife wants to get rid of the pool regardless and it was a firm “no” on $5,500, but said If I could do the repair then fine, lets keep it.

I obviously need to be able to access the drain dry so thought about two different methods to have access to the drain while not completely draining the pool. I have the benefit of a drainage area just off my property about 20 feet from the pool that tells me even after the heaviest rain the water table is about six inches below the bottom of my pool. The water table drops about another two feet in extended dry weather.

The first idea is somewhat simpler and it is to just get a bunch garbage cans, sink them upright in the pool. From there I would brace the pool using plywood against the walls and 2x4s across the mid sections. Then I would use a sump pump to drain the pool, leaving the garbage cans filled and giving me dry access to the return. Each 32 gallon garbage can full of water will weigh about 265 pounds.

My second thought would be to create a diagonal wall using 2x6 and plywood to create a triangular space by the leaking drain. It would go from about three foot out from the corner to about three foot out to the side of the pool, isolating the area of the drain leaving a triangular access. The wood would be mitered and shaped to perfectly fit the outline of the pool. I would also buy an oversized vinyl liner for an above ground pool. I would sink the liner in the pool, lay it out on the bottom of the pool, then covering up the walls and the temporary plywood wall in corner. From there, suck the water out of the corner of the pool, leaving that corner dry, water being held back by the liner.

The garbage cans seem simpler and is the way I am leaning but would love to hear any thoughts, comments or other feedback on either of the methods or an entirely different way to tackle this.

I will have other questions related to the repair, e.g., what parts to have on hand the day I do the repair, how to properly backfill as well as others, but wanted to first focus on the methodology to getting access to the drain. Thanks
 

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Yikes. We're getting into some serious math now. :hammer: Upwards pressure versus the weight from cans pressing downward, and are they adequate enough? That's beyond my skill set honestly. But you do have to address those two situations - upwards pressure and side movement as it's very possible the walls will try to bow inwards. I've seen contractors build braces that span the width of the shell in 3-4 places to prevent the bowing. I'm not sure about the garbage cans having enough counter-pressure against a potentially elevated water table. Of course if the table isn't actively rising, all is good. Places that know for sure the water is pressing upwards will drain a hole or two through the shell bottom to relieve that pressure - like removing a cork. Hopefully you won't have to do that.
 
Thanks for the feedback. Given that I can see when the water level is below the pool I was a little less concerned about the upward pressure and thinking about preventing the floor from buckling. I am going to go with the garbage can idea and brace the walls all around using two foot strips of 3/4 inch plywood and 2x4. From poking around the web it seems about half way up is the place to put the braces.

I assume that when I drain the pool the spa side will stay filled. Am I correct on that one?

Any thoughts as to what I should have purchased before draining the pool? Obviously a new drain. I believe it is piped 1.5 inch so will pick up some pipe and was planning on using Christy's Red Hot Pool Pro PVC Cement. A few sweep elbows. Anything else I should have on hand?

I know there is some debate as to using silicone vs a gasket when sealing the drains and was planning to go the silicone route. Any countering thoughts? I know I should be sanding the area smooth before installing the drain. How long would you normally wait before refilling?

I appreciate the guidance so I can keep my pool :cool:
 
You might want to call a place or two, and get a quote on removal. It will be many times what you would expect. There's the heavy equipment, the disposal of all the debris, the proper compaction of the new fill dirt, the permits and inspections your city likely requires. And then there is the relandscaping of your yard, both for the pool area, and all the damage done by the heavy equipment and the places they staged all the materials.
My wife was adamant about filling it in when we got very high quotes for replacing the 6' fence all around the yard. No pool, no need for the fence. Then the bids for filling arrived. We have the new fence, and have done other pool equipment updates. Even planning for big pool disasters, we will still be money ahead over the next many years. Here in Minn., pools aren't the best for resale value. One would think in Florida, that would be the opposite.