Paver Sand Calculator: One Screeded Inch, Then the Joints

The order that goes wrong most often on a patio is a single line reading "sand". There are two sand jobs on a paver project and they share nothing except the word. Bedding is a bulk material bought by the ton, screeded to one inch and never more. Joint filler is a bagged product swept into the gaps, and a patio that takes a ton of bedding might take four bags of joint sand. Follow one job through and both numbers fall out in the right units. The paver sand calculator handles the bedding half at 1.35 tons per cubic yard.

Marking out the patio the base already decided

The bedding area is not the paved area. It matches the compacted base underneath it, which was carried about six inches past the pavers on every unrestrained edge so the edge restraint had something to sit on.

Take a hypothetical patio 18 feet along the house by 11 feet out. The paving is 198 square feet. Add the six-inch overhang on the three open sides and the bedding footprint is 11.5 by 19, or 218.5 square feet. Use that.

Running one inch through the tool

Length 11.5, width 19, depth 1. The depth field will accept anything from 0.25 to 24 inches, but for bedding only one number is right, and a second inch of sand is the commonest cause of pavers that rock two summers later. Depth belongs in the stone, not in the setting bed.

Choose the material, decide on the 5 percent allowance for compaction and spillage, and read off cubic yards, tons and cubic feet at once. The tool also takes a circle by diameter or up to five separate areas, which suits a patio with a path running off it.

The arithmetic, since it is short:

• 218.5 x 1 / 12 = 18.2 cubic feet
• 18.2 / 27 = 0.67 cubic yards
• 0.67 x 1.35 = 0.91 tons

Order a ton of mason sand and keep the remainder for the path.

Screeding it flat and then staying off it

Set two rails or lengths of pipe at one inch, pull a screed board across them, lift the rails and fill the grooves as each paver goes down. Coarse, angular sand is what this layer wants, which means mason or washed sand rather than rounded play sand that shifts under load.

Leave the bed uncompacted before the pavers go on. The plate compactor comes over the finished surface afterwards and settles the pavers into the sand. Work standing on the pavers already laid, not on the screeded bed, and pick one material for the whole area rather than switching halfway, since two setting beds settle at different rates. Stone screenings make a firmer bed than sand and give you less room to adjust a paver by hand, which is a fair trade on a large area and an annoyance on a fiddly one.

Sweeping the joints once the pavers are down

Joints are counted in bags, not tons. For standard joints of an eighth to a quarter inch, one 50 lb bag covers roughly 40 to 75 square feet, so the 198 square feet of paving above is somewhere between three and five bags. Wider joints of three eighths of an inch and up can double that. Joint width and paver thickness both move the figure, so check the label on the bag and buy one more than the sum says.

Plain mason sand sweeps in quickly and needs topping up every season or two. Polymeric sand sets after wetting and resists weeds, ants and washout for several years, but it has to go in bone dry and be cleaned off the paver faces before it is watered, which rules out a damp morning. Sloped patios, driveways and anything with heavy traffic are worth the polymeric; a level garden path is not. Either way, the layer underneath stays plain coarse bedding sand.

Topping the joints back up after the thaw

Joints empty over a Michigan winter. Snowmelt runs across the surface for weeks, ice lifts the top of the joint, and the spring clean-up with a blower takes out whatever is left if the nozzle gets close. Expect to sweep more sand in during the first dry spell of spring, and keep a bag back for exactly that, since the joints usually drop a quarter inch after the first proper wash-in.

If the same joints wash out year after year, the sand is not the problem. Water is crossing the patio in volume, which means checking the fall away from the house and where the downspouts discharge.

Where 1.35 tons a cubic yard comes from

Dry coarse sand weighs about 2,700 lb per cubic yard, and 2,700 divided by 2,000 is 1.35 tons. At one screeded inch, a cubic yard covers 27 divided by one twelfth, which is 324 square feet, so a single yard goes further across a patio than people expect. That is also why bedding sand shows up as a fraction of a ton on most jobs while the base beneath it runs to several tons.

One tool choice worth getting right: use this page when the layer is a one-inch setting bed under pavers, and use the general sand tool when you are ordering bulk sand for leveling, backfill or bedding under something else at a depth you choose. The base beneath both is a separate calculation again, run over 21AA for that base at its own weight per yard.

When the numbers are set, put the bedding tonnage on the product page with a quantity and a date, and finish at checkout, where delivery is arranged by ZIP code and delivery and drop access sets out what the truck needs. Keep a tarp over the pile: sand that is slightly damp screeds well, and sand that has been rained on for a week does not.

Common questions

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