Washed Sand in Wisconsin: Coarse Clean Sand for Bedding and Mixing

Two sands get delivered off the same truck route and they are not interchangeable. Mason sand is fine and soft, made for mortar joints and the places a finish shows. Washed sand is coarse-grained, washed free of clay, silt and organic debris, and it exists for the parts of a job that get buried: bedding a pipe, leveling under a slab, filling around a post, going into a concrete mix as the fine aggregate. Ordering the fine one for a structural job is the mistake that costs a weekend.

If someone hands you a spec sheet that says concrete sand, this is the pile they mean.

March to November, and why a frozen pile ends the season early

• The work sand belongs to is trenching, forming and slab preparation, and all of it waits for the frost to leave. Nothing screeds flat over frozen subgrade.
• Class II state highways and posted county, town and village roads carry spring weight limits while the frost is coming out, generally early March into May and later in the north, which is worth checking before a loaded truck comes down a soft town road.
• Sand holds water. A pile that sits out through a hard frost freezes into a block, and a block will not shovel, screed or go through a mixer.
• Late autumn work is possible right up to freeze-up, but a screeded course left open over winter will want re-leveling in spring.
• The dry stretch of midsummer is the easiest time to screed, because damp sand drags and saturated sand will not hold a grade at all.

Getting a dry, covered spot ready before the sand lands

• Pick the dump spot first and make sure the truck has clear access and room to reverse out. Delivery is arranged at checkout from your ZIP code.
• Sand on bare ground picks up the ground. A tarp or a sheet of plywood underneath keeps it clean, which is the only reason it was washed in the first place.
• Cover the top as well, or the first heavy rain turns a workable pile into a saturated one.
• Have the trench cut, the forms set or the base compacted before the load arrives. Sand is the last thing in, not the first.
• Keep it away from the spoil heap. Mixing washed sand with excavated material undoes the product.
• Screed rails, a straightedge and a stiff broom do more good than an extra pair of hands on this job.

Pipe bedding, screed courses and the concrete tub

• Bedding for pipe and cable. The coarse grains flow into the haunches under a pipe and support it evenly, which is what stops a line settling into a dip.
• Concrete and mortar mixing, as the fine aggregate. Clean is the requirement: clay and organic matter interfere with the mix.
• Leveling and grading courses under a slab, a shed floor or a pad, where a thin screeded layer brings a compacted base to a true plane.
• Selected backfill in a trench, where you want material that compacts predictably rather than whatever came out of the hole.
• Around post holes, where it flows into the space and drains.
• What it is not: a paver bedding course where the joints show, and not a play sand. Those are Mason Sand jobs, and the finish is the reason.

Coarse washed sand against fine mason sand on the same site

Both are clean. The difference is grain size, and grain size decides whether a layer carries load or feathers out to a finish.

Tons for a culvert bedding run, a rock garden course and a 24 by 24 pad

Length times width times depth in inches divided by 12, then divided by 27, gives cubic yards. This site's calculator lists mason and washed sand at about 2,700 lb per cubic yard, which is 1.35 tons per yard.

• Example, bedding under 24 ft of pipe at a culvert outlet, in a trench 3 ft wide with 6 inches of sand: 72 square feet x 0.5 = 36 cubic feet, divided by 27 = 1.33 cubic yards, times 1.35 = about 1.8 tons.
• Example, a 2 inch leveling course under the stepping stones and edging of a 14 ft by 10 ft rock garden bed: 140 square feet x 0.167 = 23 cubic feet, divided by 27 = 0.86 cubic yards, times 1.35 = about 1.2 tons.
• Example, a 1 inch screed course over the compacted base of a 24 ft by 24 ft garage pad: 576 square feet x 0.083 = 48 cubic feet, divided by 27 = 1.78 cubic yards, times 1.35 = about 2.4 tons.

A cubic yard covers about 324 square feet at 1 inch, 162 at 2 inches and 54 at 6 inches. Sand is the material where it pays to order a little over, because coming up half a yard short on a screed course means a visible joint in the finished work. The sand calculator will run the figures and adds a small allowance by default.

What a screeded sand course does over its first winter

• A properly screeded and compacted course settles very little. What moves is anything that was placed loose and left uncompacted, which is why the compaction pass matters more than the thickness.
• Under a slab or a pad, the sand is protected and stays where it was put.
• Left open, it will be re-leveled in spring, because frost lifts the surface and rain washes the grade.
• Trench bedding around a pipe does not need attention again. It is doing its work below ground and the backfill above it is what carries the weather.
• Sand left over stores fine under a tarp on a pallet, as long as the water can drain out of the bottom rather than sit in it and freeze.

Measure the area, work out the tonnage, and set a quantity and a delivery date on this page. If the job is a mix of bedding and screed depths, send the numbers through the contact form and get the total checked before you order.