Foam & Sand for Pool Base

by Tim
(Saginaw, MI)

I am putting up an 18' round pool and have leveled the ground. I started putting some sand in the middle of the leveled ground, but was also planning on utilizing foam after reading some of your responses. However, I am now thinking I may have messed up.

Is it sand OR foam?? Or, can you use them together (i.e. - sand on top of the leveled ground and then the foam on top of the sand, followed by the pre-formed foam cove)? I suppose if I messed up I can try to find the receipt and take the foam back and use just sand. I just liked the idea of the nice "softer" feel using the foam, but I want to do it right.


Hi Tim.

If you are using sand under foam you should just use a small amount, just enough to smooth the dirt out. The problem with using to much sand is you will not be able to lay the foam into place without leaving a lot of footprints that will all show through the foam when the weight of the water is on it.

So, not knowing how much sand you have in the pool, you may want to remove some or possibly return the foam and use only sand.

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Foam Base For Oval Pool

My in laws want to tear down a lovely 18x33 above ground pool, no one wants to take care of it! I have been thinking about taking it to my house.

My question is, can I use 2" foam panels for the base of it? Thank you!


I have answered a lot of questions about using foam panels, and other base material, under an above ground pool. You may want to take a few minutes and read through some of them.

Pool Cove and Foam Pads

Gorilla Pad, Happy Bottom and Foam

Styrofoam For Above Ground Pool

The Best Above Ground Pool Base

Base For Above Ground Pool

Foam Pool Base

Pool Floor Pads

Pool Underlay

The problem you may have is dealing with the pressure plates. All oval above ground pools have pressure plates and you cannot leave them out. The problem is they stick up above ground level and are usually covered by a few inches of sand.

I converted a 15 x 30 oval so that I could use a foam base. I took out the raised pressure plates and replaced them with a wide thick piece of flat stock that ran down the entire side of the pool.

All oval pools have side braces. These braces are connected to channels. These channels are set into the ground with concrete blocks underneath them. The pressure plates are the only parts that go above ground level, and the only parts you need to worry about. Trying to piece foam sheets in and around them would be a little tricky. You may want to take a close look at the pool before deciding on the right pool base.

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Setting A Pool On A Foam Base

by Jedi

I am putting up a 27' x 52" resin pool (Ottawa Ont.) I have leveled the ground and put on masonry sand, leveled and packed.

I plan on using 12" round patio pads under uprights and also high density foam, and foam cove under the liner. Is it possible to lay patio pads then foam on top then base ring and then liner?

Can the foam extend past the outside of the pool? I plan on back filling the outside a little. Will frost heaving be an issue?

Hi Jedi.

It sounds to me like your plan will work. I have set pools on top of a foam base for indoor display pools, so I know that part works.

I have no idea about the long term effects of foam outdoors. I know under the liner it works out fine. It's under the whole pool I'm not sure about.

The foam extended out beyond your rail will need to be protected from bugs and birds. If you can keep critters from eating it you might be just fine.

I think you might be better prepared for frost heave using this method. If the ground rises the foam might have a little give in it and protect the pool from creasing in the sidewall. I'm not sure it works this way, but it sounds like it might.

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Above Ground Pool Underlay

by Amy

I am getting ready to install a 24'x52" round pool myself. I am so confused as to what to use and what NOT to use. I really don't want to use sand if I don't have to (a lot of work).

If my ground is fairly firm and it is leveled out, do I really need to use sand at all? Can I use 2" foam padding and then cove?

I was thinking of lying thick weed stopper material, then foam padding, cove and liner. Will that work? If I do choose the gorilla padding, can it just be that and the cove and NO sand as long as it’s level?

Hi Amy.

I use sand mainly because it is cheaper for the customer, and much faster for me, than any other type of underlay, or pool base.

There is nothing wrong with 4 x 8 sheets of foam. I have done it many times with excellent results, but boy is it time consuming. If that's what my customer wants then they provide the foam and I charge extra for piecing it all into place.

I'm not sure you need to go as thick as 2", either 1" or 1 1/2" would work just fine. You just need to be sure the ground under the foam is smooth and level. The preformed pool cove is a must when working with Styrofoam.

I think you can probably see where sand would be a lot cheaper than foam and cove. But as far as results go, I had a foam base on one of my pools and loved it.

If you go with the foam no padding is needed. You definitely do not want to install anything over the foam except the liner. If you level and smooth the ground, spray for weeds and grass if needed, you should be fine with just putting the foam over top of that.

The smoother the ground is the thinner the foam can be. On concrete, tile, or really smooth ground 1/2" foam works just fine. But use it on unleveled or rocky ground and it will fall apart under the weight of the water.

And keep this in mind as you do the pool installation. The two keys to building the perfect above ground pool are to keep it perfectly round and perfectly level.

Best of luck.

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Above Ground Pool Base Questions

by Eileen

We are replacing our liner. We have not been happy with the sand under the liner shifting. Our pool installer used 3 yards of sand for an 18' x 33' oval.

We are also wanting to fill in a small deep end and make it all level. We are planning to fill it in with dirt which has a lot of natural clay.

Could we still use Styrofoam over the sand? What do you think about liner shield? Should we get a foam pad for the bottom?

Our new installer wants to add 3 more ton of sand.

What do you think about foam for the walls?

We live in Illinois. We live out in the country so there is always a potential for critters.

Thanks so much for you site. Eileen

Hi Eileen.

Foam on the walls is a good insulator for pools that use a heater of some sort. If you don't heat your pool I would not bother. If you do foam the walls keep the foam down several inches from the top. It really gets in the way of the coping and rods that hold the liner in place.

I would not add more sand on top of what you already have. In most cases the second liners on a sand base are the best. The sand has packed down nicely. It can also be resurfaced very easily. I do this with a large push broom. Once it is all smooth again, it tends to stay that way. Adding more sand is just going to make more footprints and shifting.

The best thing to do over sand, if you really want to do something to improve your pool base, is to use something like Happy Bottom. It's a thin foam pad that works very nicely over top of a firm, packed, layer of sand. I don't like using it over fresh sand because it is impossible to keep the footprints out of the sand while you are working. All the footprints show up through the pad. Working on top of packed sand can work out pretty decent in most cases.

Styrofoam works well over packed sand also. The only drawback is the loss of water depth in the pool.

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