Pool Floor Caving In?

[Louisianajack]

I am seeking advice from those who know IG liner pools. I had a difficult time at best with my pool builder. The pool was completed in the fall of 2013 and most of our issues were resolved but I had several areas under the liner that appear to have caved in after the fill. The pool builder drained the pool last fall and repaired the caved areas. He did this by going under the liner with a semi wet mortar mix. As you can see from the attachments he was not successful. The pool is under warrenty until September 2014. My questions are
1. Why would this be happening?
2. If I press and allow them to drain and repair again, how would I know if the liner shrank in the process? How would I know if it shrank during the last drain and repair.
3. Has anyone had this issue? My concern is that it will continue or worsen.

I was not there during the floor installation or liner install. I do know it was done in the same day and it was a Portland cement and sand mixture. I only know this from the materials that were there.

I have attached some of the photos. THANKS to everyone here and the TFP method, the water is clear even at 8 feet.
Thanks in advance!

 

[duraleigh]

Hi, LJ,

First, I should preface by saying I am only guessing and have no real world experience.

It sure sounds to me like water is flowing between your pool liner and the sand (substarte) causing this erosion.

Whi is that? High water table? Fast water runoff from the surface area around the pool? Maybe a faulty French Drain system that has failed? I just don't know.

I am out of any ideas as to how to find out short of removing the liner as well.....Yikes!!

 

[Louisianajack]

Thanks duraleigh. I have not done a bucket test to check for leakage. The pool floor I have seen seems to be too hard to allow erosion. That is why I was thinking the water pressure actually pushed through the floor. Anyone in the business have any theories? I really do not know if it is better to leave it until liner replacement or ask the builder to drain and repair.

 

[Louisianajack]

Bump....anybody in the business have any input.

 

[SCon36]

I have a similar issue and my PB is coming in October to repair before closing. I first noticed a crack forming under the liner in my first full season, 2012. The PB told me that it was likely cause by our near drought conditions and that his pool had a similar crack. He said it wasn't a real issue unless the crack opened up and started pulling the liner into the crack. That's what has happened this year. I will drain the pool and they will do the repairs similar to what you mentioned above. With this post, I'll now be watching for water seeping when they peel the liner back. I will be watching your thread for people with more experience with this. Good luck with your repair.

 

[Louisianajack]

SCon36, Thanks for the input. I feel I want to have them repair it, just very concerned about liner shrinkage and my ability to know if it had.