Pool Base for an Expandable Liner

by Greg Julian
(Sevierville)

I'm installing an 18x33 with a deep end. Which is better, sand or foam? I'm just worried about having to get in the pool when filling to get out wrinkles and putting foot prints in the sand.

It's an expandable liner. I've read your way of installing the liner, just concerned with the bottom. thanks alot.


Hi Greg. The only base I recommend for an expandable liner is sand. There is no way to install Styrofoam onto the slopes of a deep area, it just does not work.

I have seen carpet used in deep areas but the results were not as good as I get with sand. I have also seen a vermiculite, concrete and water mixture used, and if done right, produces a nice uniform bottom. The drawbacks to that method are that any footprints, or indentations, in the pool base, caused at any time before the mixture is completely set, will stay there. It's difficult to go back at a later time and re-smooth the area. The other drawback is the wrinkle thing, hopefully you won't have any, but if you do, a smooth, hard, surface makes getting rid of them nearly impossible. Sand will give, allowing you to work out any wrinkles and then go back and smooth the areas out, as best possible.

Deep ends are tricky, especially on oval pools. Some liners go in nice while others won’t. What you hope for is that you can get the deep end full without wrinkles. The shallow areas are much easier to work the wrinkles out of.

Water and pack the sand as well as possible so that if you do have to get in the pool the damage will be minimal. What we try to achieve is never getting in the pool. If you can somehow get the majority of the pool bottom wrinkle free, leaving them just around the edges, you can lean over the pool structure, once the top rails are back in place, and work them out without ever getting in the pool.