Installing Your Pool, Stage 5: The Cove, The Sand Base, And The Uprights
Where you are: your wall is standing in a complete circle, seam bolted, stabilizers on, grounded, and held up by support bars. If you are not there yet, go back to stage four.
What you will have finished with: a finished sand base with a cove around the inside edge, and uprights installed all the way round holding the wall on their own.
After the wall, this stage feels calm. You are back on the ground with hand tools and no time pressure. It is also the stage that quietly determines how long your liner lasts, so it is worth doing carefully rather than quickly.
First: check your radius one more time
Before you build the cove, your assembly instructions ask you to confirm that the radius of the pool is correct from the centre.
This is your last practical chance to catch a circle that has drifted. The wall is up but nothing is permanent yet, and a small correction now is a great deal easier than discovering the problem when the liner will not sit right.
Measure from the centre to the wall at several points around the circle. If they match, carry on.
What the cove is, and why it exists
The cove is a bank of material running around the inside base of the wall, filling the sharp right angle where the wall meets the floor. In cross section it is a triangle.
It does one job, and your instructions state it plainly: it protects the liner from the cutting edges of the bottom wall tracks and from the stone dust underneath.
Think about what happens without it. Your liner is pressed into that corner by thousands of gallons of water, with the whole weight of the pool pushing it down onto the exposed edge of a metal track. Vinyl against a cut edge, under constant pressure, for years. That is how liners fail early at the seam.
The cove turns that sharp corner into a gentle slope. The liner curves over it instead of being forced into it.
This is not an optional refinement. It is one of the highest-value twenty minutes in the entire installation.
Two ways to build it
A sand cove. Spread approximately 4 inches of compacting sand all around the inside base of the wall, and shape it into a smooth ramp. The instructions show it rising about 4 inches up the wall and tapering out roughly 12 inches onto the floor.
A prefabricated cove. These are ready-made foam or plastic sections that you fit around the inside base of the wall. They install faster, give a consistent profile all the way round, and do not wash out or get walked flat while you are working. If you have them, use them.
Our post on what pool cove is and whether you need it covers the choice in more detail.
Building a sand cove properly
If you are shaping sand rather than fitting prefab sections:
Work all the way round before you start shaping. Get sand distributed around the whole perimeter first, then shape. Shaping as you go tends to produce a cove that is generous where you started and thin where you finished.
Aim for a smooth, even slope. No steps, no lumps, no thin spots. Run your hand or a length of board along it to check.
Pack it firmly. Loose sand does not hold a shape and will slump the moment the liner presses on it. Damp sand packs much better than dry.
Check that it actually meets the wall. A gap between the cove and the wall leaves the track edge exposed, which defeats the point.
Keep it consistent in height. An uneven cove shows through the finished liner as a wavy line around the base of the pool.
Finishing the sand base
With the cove in place, finish the floor itself. Your instructions give three steps.
Level the finishing sand one last time. This is the surface your liner sits on, and every imperfection in it will be visible and felt underfoot for the life of the pool.
Remove any sharp stones, debris or roots from the surface. Go over the whole floor deliberately. Anything sharp left here is directly under vinyl that will be under pressure.
Spray the sand with water and pack it once more until the base is nicely even. Damp sand compacts far better than dry and holds its shape. This is the step people skip because the base already looks finished, and it is the one that stops your floor developing dips and footprints later.
Then stay off it. Light, flat-soled shoes from here on. Your instructions warn that the slightest heel mark can be visible once the pool is filled, and they mean it. If you have to cross the base, tread lightly and rake out your tracks.
Optional: wall foam
Not part of the manufacturer's sequence, but worth knowing about since this is roughly when it goes in.
Wall foam is a thin padding applied to the inside face of the wall, giving the liner a softer surface to rest against and smoothing out the corrugation. It is comfort and liner protection rather than structure.
If you are using it, fit it now, before the liner goes in. Our post on wall foam covers whether it is worth it for you.
Same for a liner floor pad, which goes down over the finished sand base.
Installing the uprights
Now the pool starts holding itself up.
Which way up
Your instructions flag this specifically, and it is the kind of thing that is easy to get wrong and annoying to undo:
The vertical posts have a top and a bottom. The one with the rectangular hole is to be the top.
Check every upright before you fit it. Fitting one upside down means taking it off again, and if you fit several before noticing, that is a frustrating half hour.
How they attach
Each upright is secured to a foot collar or connector at the bottom, depending on your kit. Line up the holes on the connector with the holes on the bottom of the post, and secure with screws through those holes.
Take a moment with the first one to understand how the parts fit together, then the rest go quickly.
Work progressively around the circle
This part is general practice rather than an instruction, but it matters.
Do not pull all your support bars out and then start fitting uprights. Replace them one at a time as you work around the pool, so the wall is supported continuously. Fit an upright, secure it, then move the freed support bar ahead to the next position if you need it.
Keep the posts vertical. Eyeball them against the wall, or use a small level. A post leaning slightly now becomes a top rail that will not sit correctly in stage seven.
Work opposite sides if you can. Fitting a few, then moving across the circle, then coming back tends to keep the wall more evenly supported than working steadily round in one direction.
Do not over-tighten
The same principle from the wall stage applies. These are screws into relatively thin material, and stripping the fixing point is much easier than it sounds. Firm is enough.
What good looks like
- Cove complete all the way round, smooth, packed, meeting the wall with no gaps
- Sand base level, clear of anything sharp, dampened and packed
- No footprints or tool marks on the finished base
- Every upright fitted the right way up, rectangular hole at the top
- Uprights secured to their collars or connectors and standing vertical
- Wall supported by uprights rather than by support bars
Before you move on
- Radius rechecked from the centre before building the cove
- Cove built all the way round, roughly 4 inches high, tapering onto the floor
- Cove packed firm and meeting the wall with no gaps
- Finishing sand levelled a final time
- All sharp stones, debris and roots removed from the surface
- Base sprayed with water and packed until even
- Wall foam and floor pad fitted, if you are using them
- Every upright checked for orientation, rectangular hole at the top
- All uprights secured to collars or connectors
- Uprights standing vertical
- Support bars removed progressively, not all at once
- Flat-soled shoes throughout
The short version
- Recheck the radius from the centre before you build the cove.
- The cove protects your liner from the cutting edge of the bottom track. It is not optional.
- Build it about 4 inches high, tapering roughly a foot onto the floor, or fit a prefabricated cove.
- Pack it firm and make sure it meets the wall with no gaps.
- Level the base a final time, remove anything sharp, then spray with water and pack it once more.
- Flat-soled shoes from here on. Heel marks show through the liner.
- Uprights have a top and a bottom. The rectangular hole goes at the top.
- Replace support bars progressively as you fit uprights, not all at once.
- Keep the posts vertical and do not over-tighten the screws.
Next in this series: installing the liner. That stage has more technique in it than any other, it is very sensitive to temperature and timing, and there is a shop vacuum trick in your instructions that makes an enormous difference.
