Sand Calculator: A Pool Pad on a Hillside Lot, Start to Finish

Very little ground in this state is flat enough to set a pool on as it lies. A yard that looks level by eye usually has six or eight inches of fall across twenty feet, which is fine for grass and not fine at all for a wall of water. This page follows one job the whole way through, because the sand is the last stage of it rather than the first, and the quantity only makes sense once the earlier stages are done.

Getting the ground flat before any sand gets ordered

Cut into the slope rather than building out from it. Ground you dig into is ground that has been sitting there for decades; ground you add is only as firm as the compaction you give it, and clay that has been rained on does not compact well in a hurry. Take the high side down to meet the low side, and keep the cut face back far enough that it is not crumbling into the pad.

If the low side has to come up more than a couple of inches, that is fill dirt and lifts, not sand. Sand poured into a dip will find its way out under the liner in the first season. Size that part with the dirt calculator and let fill dirt do the structural work, compacted in lifts before anything else goes down.

Check the finished cut with a long board and a level, not by eye, and strip every root and stone out of it while you are there.

Measuring the circle you are covering, not the pool you are filling

A 13 foot pool does not want a 13 foot pad. Give yourself 18 inches of working room all round so the wall has somewhere to sit and you have somewhere to kneel. That makes a 16 foot circle out of a 13 foot pool, and the difference is not small: the area goes up by half.

Measure across the widest point of the finished pad in feet. If you have already pegged it out, run the tape from peg to peg through the center rather than around the outside.

Entering 16 feet across and 2 inches deep

Switch the tool to Circle and enter 16 in the diameter field. Depth goes in as inches, and 2 is the figure for a pool base of mason sand, screeded smooth. Choose the sand from the material list so the weight is that material's own, and tick the five percent compaction and spillage box, which on a job like this covers what ends up on the tarp rather than in the ring.

Here is the working, as a hypothetical. The area is 0.7854 x 16 x 16 = 201.1 square feet. 201.1 x 2 = 402, divided by 12 gives 33.5 cubic feet. Divided by 27 that is 1.24 cubic yards, and at 1.35 tons a yard, 1.67 tons. With the five percent, 1.76. Order one and three quarter tons and keep the last wheelbarrow-load for the low corner that always shows up once you start screeding.

The tool also takes Rectangle and Multiple areas, up to five pieces in one total, which is how a pad plus a sandbox plus a strip of leveling sand becomes one order rather than three deliveries to think about.

Screeding it flat, and keeping anything sharp away from the liner

Rake the sand out roughly, then screed it with a straight board pulled across two rails set level. Work damp rather than dry; sand that has just been rained on will not screed at all, and sand that has been baked in an August sun runs away from the board. Firm it with a hand tamper, check it again with the level, and pick out every pebble you find, because a stone the size of a pea under a liner is a stone you will meet again.

Have the load tipped somewhere firm and close, and put a tarp over it if it is going to sit. Wet sand smears instead of spreading.

Mason, washed, and the sand that belongs on another page

Mason sand has the finer, more even screen. It is what goes under a pool liner, into mortar and into paver joints, because it screeds smooth and has nothing coarse in it. Washed sand has had the clay and silt rinsed out, which makes it the one for sandboxes, concrete batches and general bedding. Both convert at the same weight, so the calculator gives the same tonnage whichever you pick.

Two jobs on this site are sized elsewhere. The one inch bedding course under pavers is thinner and fussier than anything here, and it goes with its own joint sand, so it has the paver sand calculator to itself. Compacted stone under that bedding is a different layer again. And if you are leveling a lawn, blend the sand through the top of the soil at a quarter to a half inch a pass rather than laying it as a layer, because straight sand over Tennessee clay makes a shelf that roots will not cross.

For a sandbox, 6 inches of washed sand is a playable depth. A 5 by 7 box comes to 35 square feet, so 35 x 6 = 210, divided by 12 is 17.5 cubic feet, divided by 27 is 0.65 cubic yards, and 0.88 tons.

What 2,700 lb a cubic yard does to the two numbers on screen

Dry sand weighs about 2,700 lb a cubic yard, which is 1.35 tons, and that is the multiplier behind every tons figure above. Soaked, the same yard is heavier, but that is water, not sand: the volume has not changed and neither has what you should order. Rain affects the shovel and the screed board, not the quantity.

Turn it around and it becomes a coverage figure. One ton is 0.74 of a yard, or 20 cubic feet, so a ton spreads about 240 square feet at an inch, 120 at two inches, 80 at three and 40 at six. Sand is ordered by the ton here, the same as the stone, so take the tons line to the product page, pick a quantity and a date, and let the checkout sort delivery out by ZIP code.

Common questions

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