Washed Sand: Clean Coarse Sand for Ohio Trench and Slab Work

Trench and slab work in this state runs on a weather window rather than a schedule. The ground has to have thawed and given up its winter water before a cut will stand square, and the work has to be finished before the first hard freeze, because you cannot compact backfill into frozen ground and you cannot pour onto it either. On the northwest flats that window opens late and on a gravel valley terrace it opens weeks earlier, which is why two jobs twenty miles apart can start a month apart.

Clean sand is the material that makes the most of a short window, because nothing about it has to cure, settle or wait.

Gray, gritty and free of clay: what a washed load looks like next to pit sand

Take a handful and squeeze it. Damp pit sand holds the shape of your fist and leaves a film on your palm, because there is clay and silt through it. A washed coarse sand crumbles apart as soon as you open your hand and leaves your palm clean. That is the whole difference, and it is the difference that matters in a concrete mix, where clay coating the grains weakens the bond with the cement paste, and in a drainage detail, where the same fines are what clogs it.

It is coarse rather than soft, so it feels gritty rather than silky, and it pours and flows into a confined space more readily than a fine sand does. It is not a play sand and it is not a fine jointing sand.

Where washed sand belongs on an Ohio job

Pipe and cable bedding is the clearest case. A clean sand conforms around a line, supports it evenly instead of point-loading it on a stone, and does not bring clay into the trench that the drainage detail is trying to keep out. Work it in around the haunches of the pipe before covering, and compact the backfill in lifts as the trench closes.

Concrete and mortar mixing is the second, where the washed grading is what makes a batch predictable from one mix to the next.

Leveling and grading is the third: correcting low spots, forming a fall on a site, and building a flat, compacted surface before a slab. On till clay, sand under a slab also gives water a layer to move through instead of sitting directly under the concrete through a freeze cycle, though it does not replace the need for the water to have somewhere to go.

Backfill around foundation excavations and post holes rounds it out, because it compacts in a confined space where a clay backfill will not.

A path, a lawn and a hot tub pad are where sand lets you down

Three jobs come up often and none of them is a sand job.

A garden path laid on loose sand goes wavy inside a season. Foot traffic pushes sand aside at every step and it washes out of the edges in a downpour. A hypothetical 50 foot path at 3 feet wide is 150 square feet, and at 2 inches that is 25 cubic feet or 0.9 of a yard, which wants to be walkway gravel over a compacted base rather than sand.

New lawn prep needs growing medium. Sand spread over clay in the hope of improving it produces neither, and in quantity it can make a heavy soil worse. Top soil over corrected levels is the answer, with fill dirt doing the raising.

A hot tub pad carries a concentrated load and has to stay level through a freeze cycle. Sand alone moves under that. An 8 by 8 pad at 6 inches is 64 square feet, 32 cubic feet, about 1.2 cubic yards of compacted 304 aggregate base, with a thin leveling course over it and the sand kept out of the structural part entirely.

How thick a lift goes, and why the figure is the compacted one

Bedding under a pipe is usually 4 to 6 inches of clean sand on a trimmed trench bottom, with the same material brought up around and over the line before the general backfill goes in. A leveling course under a slab or a paver base is thin, an inch or two, because sand is a bedding material and thickness in it is movement waiting to happen.

Quote every figure as the compacted depth and order above it. Sand loses noticeable volume when it is tamped and watered in, so a lift placed at the finished depth will be short once it is compacted. And on wet ground, take the trench bottom back to firm material first: a clean sand bedding placed on soft muck transfers the softness straight up to the pipe.

Cubic yards for a 70 foot service trench and a 10 by 12 slab

Take a hypothetical service trench, 70 feet long and 2 feet wide, with 6 inches of bedding.

• Area: 70 x 2 = 140 square feet
• Depth: 6 inches = 0.5 feet
• Volume: 140 x 0.5 = 70 cubic feet
• Cubic yards: 70 / 27 = 2.6 cubic yards
• Tons: this site figures mason and washed sand at roughly 2,700 lb per cubic yard, about 1.35 tons per yard, so 2.6 x 1.35 = about 3.5 tons

And a hypothetical slab leveling course, 10 by 12 feet at 2 inches:

• Area: 10 x 12 = 120 square feet
• Depth: 2 inches = 0.167 feet
• Volume: 120 x 0.167 = 20 cubic feet, or 20 / 27 = 0.74 cubic yards, roughly a ton at the same approximate weight

A machine-cut trench finishes wider than the line you marked, so round the trench figure up. The sand calculator will run the same measurements if the trench changes width along its length.

The other sand on the site, and what to pair it with

Mason sand is the finer, softer one, used for brick and block work, paver joints and play sand. This one is the coarse, clean, structural one. Where a job calls for both, they are not interchangeable and a fine sand in a concrete mix will not behave.

For a pipe run, pair it with a clean stone: #8 crushed stone where the bedding has to drain hard, or #57 limestone in the drainage layer around a larger collector.

Work out the trench and the slab separately, then pick a quantity and a delivery date on this page. Delivery is arranged at checkout once the ZIP code goes in, and the truck needs a clear approach and room to raise a bed, so settle on the drop spot first. Ohio Rock Supply can look over a split order through the contact page if the material is needed in two places on the same site.