Liner Issue`


Well-known member
Oct 27, 2011
Chicago, IL
I posted a couple of years ago that I've been having some issues with protrusions on my liner. I have two ball shaped protrusions on north side of my pool. These protrusions haven't gotten worse (see image - ball shaped) since last year, thankfully. However, I am seeing some new horizontal protrusion on the west side of the pool (closest to my fence). They were there in prior year but look to have gotten worse, see images, one with flash, one without.

In these areas, there is concrete behind the liner. The protrusions are hard and do not move when prodded. What the heck could these be caused by?

This liner is 4 years old and the prior liner that I replaced was 12+ years old, with no protrusions. The only thing that I could think of that has changed is the house behind me (southwest of me) was demo'd and their lot has a slope (see pics). I would think that the protrusions would happen all over the south side of my pool, which currently has none. The slope is somewhat towards my house but the biggest slope is to the lot behind my house.

Also, I noticed that the return jet had a slow leak (which I fixed last year and checked this year) and is located on west side where the large horizontal protrusion is, so I thought that may have contributed to the problem but it hasn't gotten worse since last year so maybe not?

I essentially live next to a forest preserve, so there are massive trees everywhere. But most are pretty far away from pool/house.

I have a few questions:

1) Thoughts on what could cause these types of issues?
2) If we think it has to do with the house being demo'd (see pictures showing slope) and the grade of lot, should i install a drain tile of sorts to move water away? If so, how deep?
3) Anything else I can do? I already dug a 1 ft trench to bury some galvanized hardware cloth and cut some small roots, but nothing major so far. I plan on installing hardware cloth around perimeter of pool. currently have some installed but small animals can get in.