Dirt Under Bottom Rail

by Joel Johnson
(Springfield, Illinois)

Does the ring/track that the wall sits in need to be at ground level? I've placed them on 8" pavers and leveled them to within .25". One side of the ring is pretty flush with the dirt; the other has a 1" gap between the track and the dirt floor.

I'm bringing in sand to level inside the ring and this pool will be sunk into the ground 20".

I live in Illinois.

Hi Joel.

I would not leave the gap there. You have done such a good job so far. Don't take short cuts. The bottom rails should all rest on firm solid ground, not sand. It would not take that long to pack dirt under the rails, or even place blocks under the rails, just not sand.

blocks for pool bottom rails

If you already have blocks set all the way around, like in the photo, then I would level the inside with dirt. The thing with sand is the deeper it is the more likely you are to have footprints. So using to much sand in any one area could be a problem down the road a ways.

Once the pool is set and the dirt around it backfilled you would be just fine, the thing is, the pool has to have plenty of water in it before you start backfilling. So being in the ground makes no difference, the pool needs to be built like it was sitting on top of the ground.

There is one other consideration to make when setting the rails sitting on dirt. Make sure there is no rise between the footplates, this caused the wall to crease.

Comments for Dirt Under Bottom Rail

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Jun 13, 2018
15' Pool Bottom and rails
by: Chett

I live in Northern California with Hard Clay Soil.
I have read somewhere that if I cannot get the center area totally level with no bumps that I can use a thin layer of crushed limestone then tamper that then using sand or a preformed pad on top of that instead of sand. My questions are as follows:

1. If I do not want to use sand where may I get a preformed pad for the bottom? Please note that I purchased a bottom pad with my pool that lays on top of the sand.

2. If I cannot get the perimeter level for the rails I also read that I can make a trench around the perimeter and fill it with highly packed gravel (tampered) and use that to lay the rails on. If this is a valid solution how far under the liner should the trench extend and how wide of a trench? (I will still use my concrete blocks which are deck pylons that will be inserted with the narrower end down.

3. when I use blocks I presume the not only the plates are properly centered on the blocks but the bottom rails are going to intersect the blocks as well? meaning the some portions of the rails are going to rest on the blocks?

4. Any material that you can think of that I can cover the blocks with so that the blocks do not puncture or scratch the liner?

Thank You so much.

Hi Chett You need to start with a smooth level base, even if that means going over the entire area with something like a crushed granite. Then you can use a thin layer of well packed sand with your pool pad over it.

If you go over the entire area with a crushed top coat you don't need to worry about the outer edge where the footplates and bottom rails sit. Be sure to laser level every block and you should be fine. And yes, some portion of the rails will sit on the blocks.

Your blocks will be covered by sand and a liner pad, they will be no where near the liner.

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Bottom Rail Placement


I have an older Doughboy above ground pool with a wood tone finish. It is a 16 x 32. It has 10 long bottom rails, 6 medium rails and 4 shorter ones. I am not sure where the different sizes go. Please let me know.

Hi Dean.

Doughboy ovals use three different bottom rails. They are side rails, transition rails and end rails. They are stamped on the inside curve of the rail. The stamp will say S, TR and 16.

Doughboy oval pool bottom rails

The four transition rails go at the ends of the side braces, or the four corners of the pool. They transition the side of the pool into the end. So each end will have a transitions rail, 5 end rails and another transition rail. The rails marked S belong on the side. This photo shows three rails. At the bottom is the last end rail, marked 16, then the transition, marked TR, then the side rail located between the first two side buttresses.

The photo also illustrates how we install most of out pool liners, by stretching them into place. Be sure to read out pages about installing pool and liners.

Above Ground Swimming Pool Installation

Above Ground Pool Liner Installation

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Unable to get our Above Ground Pool Installed

by Bridgette
(Sherman, TX)

Hello, we have been trying to get our above ground pool installed all summer. Everything is up and ground is level but the wall overlapped, so we got the wall together, but now the bottom and top rails have gaps.

Please any suggestions are welcomed. Thanks in advance.

Hi Bridgette.

Proper gaping of the bottom rails can be one of the trickiest parts of pool building. For one, they are never the same. And secondly, it must be done correctly.

above ground pool bottom rail gap

By correctly I mean your goal is to have every bottom connector set with the same rail gap. And to have your pool completely round.

This page shows a foot plate and explains rail gap.

Diamond Star Pool Installation

On many occasions this means installing the wall just to see how much overlap you have, or how shy you are of making a connection. You then take the entire wall out and re-gap your bottom rails and make the entire pool round again. The wall then gets re-installed and hopefully will be very close to lining up. If it's within an inch you can back it out for about five rails or so and re-gap that section.

Having bottom rail gaps that are not even makes installing the top rails twice as hard as it needs to be. Top rails have pre-punched holes in them and they need to be equally spaced. That means for the uprights to be straight up and down, the bottom rail gaps need to all be the same.

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Jun 07, 2018
Bottom rail gaps
by: Anonymous

We had some bottom rail gaps also as our ground is unworkable shale on a hillside.

Once we set the blocks level and installed the bottom rail, we then mixed a bag of concrete and packed the concrete under the bottom rail everywhere there was space. It took about 1/2 a bag of concrete and 45 minutes.

Concrete won't wash out and will form perfectly right under the rail

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Sea Isle or Bermuda king

by Karen Williams
(Renick, NO 65278)

We bought a used pool and the wall poles are attached to the bottom plate and I think it would be pretty hard to get them off. Can I install the pool with the poles attached?

Hi Karen

It is possible to do with the uprights attached, but very difficult. It is better to find a way to get them off.

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