StoryPole/Sitework

Sand by the ton, dug by the yard

You calculate sand in cubic feet and buy it by weight. Compaction sits between the two, and getting bedding depth wrong is what ruts a patio two summers later.


Section
Section through the sand layer drawn to scale
The job

Sand ticket
tons Enter an area to start

Volume in, weight out

Sand is quoted by the ton at the pit and by the yard on a delivery ticket, but you size it by area and depth. Dry concrete sand runs about 100 lb per cubic foot, so a cubic yard weighs about 2,700 lb — 1.35 tons. Damp sand from an open stockpile runs nearer 1.5 tons a yard, because water fills the spaces between grains without adding much volume.

That difference is worth knowing before you argue with a scale ticket. The same yard of sand can weigh a couple of hundred pounds more after a wet week.

The one inch rule

Bedding sand under pavers is one inch, screeded, and not compacted before the pavers go down. It is a setting bed, not a levelling layer.

Every wavy patio started as someone using bedding sand to fix a base that was not flat. Sand migrates under load. A thick bed pumps and ruts wherever the wheels or feet go, and no amount of compaction afterwards brings it back. Low spots belong in the compacted base underneath, where they can be fixed properly.

Compaction

Crushed stone base loses roughly a fifth to a quarter of its loose volume when it is compacted, so order to the loose figure rather than the finished depth. Compact in lifts of no more than four inches — a plate compactor does not reach the bottom of an eight inch dump, and the part it misses settles later.

Screeded bedding sand takes no compaction allowance because you do not compact it before laying.

Bags or bulk

Quantity50 lb bagsSensible?
½ cu yd27bags fine
1 cu yd54borderline
2 cu yd108order bulk
5 cu yd270bulk, obviously

A 50 lb bag holds about half a cubic foot. Past a couple of yards the bags cost more than the delivery and take a day to move.

Questions

How many tons in a yard of sand?

About 1.35 dry, 1.5 damp.

Can I use play sand under pavers?

No. Play sand is rounded and fine, so it will not lock up under load. Bedding wants angular washed concrete sand meeting ASTM C33.

What about the silica warning on the bag?

Real, and it applies to dry sweeping and cutting rather than handling damp sand. Wet-sweep polymeric sand off pavers and use a saw with water or dust extraction on any cutting.

Estimate for ordering. Densities vary with grading and moisture, and suppliers sell in their own increments. Bedding and base depths here follow common paver practice — a driveway, a retaining structure or anything carrying vehicles should follow the design for that job, not a default.