Mason Sand in Wisconsin: Fine Washed Sand for Joints, Mortar and Play

Two jobs account for most of the Mason Sand that goes out across this state in a summer: a mortar tub on a block or brick job, and the joints of a flagstone or paver surface that has to survive the next freeze and thaw without opening up. Both want the same thing from the sand, which is fine, even grain and no clay or silt riding along with it. Neither has anything to do with what is holding the surface up, and that distinction is where most of the ordering mistakes on this product start.

Mortar tubs and paver joints: where the summer orders go

• Size is ultra-fine with a consistent grain, so it mixes evenly and sweeps into a narrow joint without jamming.
• It is washed, which takes clay, silt and organic material out. Clay in a mortar mix weakens the joint; silt in a paver joint turns to mud and grows weeds.
• The grain consistency is what makes a mix repeatable from one batch to the next, which matters when you are matching mortar color across a wall.
• Soft enough underfoot and in the hand that it also does duty in sandboxes, volleyball courts and beach-style features.

Order Mason Sand when the finish shows, skip it when the load goes through

Choose it if:

• You are mixing mortar, stucco or grout and need fine aggregate.
• You are sweeping joints on pavers or flagstone.
• You are screeding a thin, even setting layer on top of a base that is already built and compacted.
• You are filling a sandbox or surfacing a court where bare hands and feet are involved.
• You are leveling ground under something light that sits still, like an above-ground pool wall or a bed frame.

Skip it if:

• The layer has to carry a vehicle, a structure or a footing. Fine sand does not carry load.
• You need aggregate for a concrete mix. That is a job for coarser Washed Sand, the one Wisconsin buyers call concrete sand.
• You are trying to fill a low spot or raise a grade. Use Fill Dirt for bulk and keep sand for the finish.
• The surface will have water moving across it. Fine sand washes out of joints and off slopes quickly.

Flagstone joints, sandboxes and a court that drains after a thunderstorm

Mortar and stucco work. Fine aggregate is what makes a mix spread cleanly off a trowel and set into a solid joint. Because the sand is washed, you are not introducing clay that would weaken the bond or cause staining as the wall weathers.

Paver and flagstone joints. Sweep it in dry, in passes, wetting and re-sweeping until the joints stop taking sand. Flagstone with wide, irregular gaps takes several sessions over a few days as the stones settle. Expect to top joints up after the first winter, because frost movement always reopens a few.

Sandboxes and play areas. Washing removes debris, so what is left is clean and comfortable to dig in. Build the box with drainage under it, because sand that never dries out is sand that grows things.

Courts and recreation surfaces. A level, soft playing surface needs depth to absorb a landing and a free-draining layer beneath it, which matters on Wisconsin clay, where a court built straight onto tight lake-plain soil will hold water after a thunderstorm for days.

Mason Sand sits on the base, it is not the base

Wisconsin frost goes at least 48 inches down under a footing, and a patio has nothing like that depth to work with. What keeps pavers flat through a thaw is the compacted layer underneath and the drainage below it, not the sand.

• Build the load-carrying layer from 3/4" Traffic Bond, or from Breaker Run where the ground is soft, and compact it in lifts.
• Keep the setting layer thin and even. A deep sand bed does not stabilize a patio, it gives it somewhere to move.
• Get water out from under the build. Saturated clay under a patio is what heaves it, and sand will not save a build that is sitting in water.
• Then use the sand for its actual job: screeding the setting layer flat and filling the joints.

Many Wisconsin paver installers bed on Screenings instead and keep the fine sand purely for joints. Both approaches depend on the same thing underneath.

Working out sand for a flagstone run, four raised beds and a play area

Square footage times depth in inches divided by 12, then divided by 27 for cubic yards.

• Example, a flagstone walkway 3 ft wide and 34 ft long with a 1 inch setting bed: 102 square feet x 0.083 = 8.5 cubic feet, divided by 27 = 0.31 cubic yards, about a third of a yard, plus a little for the joints.
• Example, leveling under four raised vegetable beds, each 4 ft by 8 ft, with a 2 inch screeded pad under each frame: 128 square feet x 0.167 = 21.3 cubic feet, divided by 27 = 0.79 cubic yards. The sand levels the frames; what goes inside them is Garden Soil, sold here as garden mix.
• Example, a 20 ft by 24 ft playground surface at 6 inches: 480 x 0.5 = 240 cubic feet, divided by 27 = 8.9 cubic yards.

This site's calculators put mason and washed sand at about 2,700 lb per cubic yard, roughly 1.35 tons per yard, so the weights are approximate. That makes the walkway bed 0.31 x 1.35 = about 0.4 tons, the raised bed pads 0.79 x 1.35 = about 1.1 tons and the playground surface 8.9 x 1.35 = about 12 tons.

Small sand quantities are easy to underestimate, because joints swallow more than you expect and a screed bed is never perfectly even. Work the figure, then give yourself a margin. The calculator handles the conversion from cubic yards to tons.

Pick your quantity and a delivery date here, or email the measurements through the contact page if you would rather someone checked the joint allowance with you first.