Repairing floor under vinyl

Sq1873

Member
Apr 16, 2021
8
Montreal
Pool Size
7000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi everyone,

I have an old inground pool that I inherited from the previous home owner who patched their (very old) liner in one spot. As I was looking into replacing the liner with a new one I noticed that the floor has an irregularity which seemed to be close to the spot where the old liner was patched. So I'm wondering if that was the root cause of the hole in the liner.

Unfortunately I didn't think of taking a picture when I opened it up but the floor looks like concrete to me but it is generally smooth looking like someone "painted" it with cement on top. That particular spot seems to have that top part removed so you can see "normal" concrete with small rocks in it. I think some of those rocks have edges sticking out that are sharp enough to damage the liner.

What kind of top layer is normally put on concrete pools floors and what's the best option for repairing that?

Thanks!
 

Pool_Medic

In The Industry
Apr 1, 2018
1,454
Bangor Maine
It’s more than likely vermiculite, similar to grout. The new installer should have those spots pointed out and he can fix before he drops in the new liner.
 

Sq1873

Member
Apr 16, 2021
8
Montreal
Pool Size
7000
Surface
Vinyl
Chlorine
Liquid Chlorine
Well, I am the new installer :)

I thought it might be vermiculite but I then found that it is supposed to be squishy and what I have is not squishy at all. Maybe it's grout but would that be durable under these pressure and moisture conditions? It's gray just like concrete but without any rocks and looks like, not sure what this application method is called but you can see strokes just like what a grout float would leave. I think I might just need to apply the same stuff to the spot where it is missing but not sure if that would bond to the existing surface appropriately or I would be better off with epoxy, polyurethane or something else. It's a fairly round spot maybe 5-10" size.
 

Sq1873

Member
Apr 16, 2021
8
Montreal
Pool Size
7000
Surface
Vinyl
Chlorine
Liquid Chlorine
Ok thanks, must be some sort of mistake in that info I found then.

Would this be repaired by putting a patch of fresh vermiculite? Would that bond properly just on its own or is it trickier than that?
 

duckcmmndr

Bronze Supporter
May 7, 2014
170
Arkansas
Pool Size
29980
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
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