Washed Sand in Michigan: Clean Coarse Sand for Mixes, Bedding and Leveling

Nearly all the washed sand ordered in this state disappears the week it arrives. It goes into a concrete mix, under a buried line, around a footing or under a slab, and by the time the job is photographed there is nothing of it to see. That is the job it gets bought for here: the clean, controlled layer you put in before something gets covered up, on ground where the frost reaches 42 inches and anything trapping water under a build will be found out by April.

What does washing actually take out, and why does that matter here?

It takes out the clay, the silt and the plant debris. What is left is a coarse-grained sand with a consistent particle size and nothing in it that swells, slumps or rots.

Both halves of that description earn their keep on Michigan ground. Clay and silt in a bedding sand hold water, and water under a slab or beside a footing on the flat southeastern lake plain is exactly the problem you were trying to design out. Organic material in a backfill breaks down and leaves voids, and voids under a build become settlement. And in a concrete or mortar mix, fines throw the water content out and weaken the result, which is why a mix sand is specified washed rather than dug.

There is a second reason clean sand matters here specifically. On the sandy west side and up north it is tempting to use what is already on site, and native sand looks similar. It usually is not. Dune and outwash sand varies in grading from one end of a lot to the other, and it commonly carries silt or organic material through it.

Can it level the low spot behind the garage before the shed goes in?

For a shallow regrade under something that is about to be built on, yes, and that is one of its listed jobs: bringing a prepared area up to level and setting a pitch before the next stage. It moves into hollows readily, it compacts predictably, and it does not change volume much once it is wet.

Two cautions. The first is that sand is a leveling material, not a filling one. If the low spot is deep, the bulk of it should be Fill Dirt compacted in lifts, with sand only doing the last few inches of finishing. The second is that the area has to be cleaned out and prepared first, because the point of a clean fill is lost if the surrounding soil mixes into it as it goes in.

Does the culvert pipe under the drive get bedded in washed sand?

The pipe, yes. Bedding is one of the things this material is made for. Placed evenly under and alongside a pipe or a conduit, it beds the line along its whole length rather than letting it bear on high spots, it fills the haunch area beside the pipe where voids otherwise form, and it does that without the sharp faces that damage a coating.

The ditch and the outlet are a different question, and the answer is no. Anything that moves water at speed will take sand with it. Ditch lining and outlet armor are jobs for RipRap, or for #4 Crushed Stone where the flow is smaller. Bed the pipe in sand, armor the ends in stone.

Would it work under a rock garden bed by the cottage steps?

Probably not the way you are picturing it. A decorative gravel or rock bed is usually built as fabric over prepared soil with the stone laid on top; a sand layer under fabric on clay simply becomes a wet layer, and on already-sandy ground it achieves nothing at all.

Where a leveling course does help is under something set into the bed that has to sit flat: a stepping stone, a flagstone landing, a plinth. For that, a thin, screeded bed is reasonable. For the bed itself, put the effort into edging and into River Rock or Pea Stone at a sensible depth.

When in the year should a sand load land?

Between the thaw and the hard freeze, and closer to the middle of that window than either end. Sand placed into a wet spring excavation is difficult to compact and difficult even to move, since saturated sand is heavy and sticky. Sand delivered in late autumn can freeze in the pile before you get to it, and a frozen heap of sand is a job for a pick rather than a shovel.

The northern Lower Peninsula and the Upper Peninsula have a shorter version of that window than the south. If the job is a pour or a buried line, plan it around when the ground will be workable rather than around when you would like it done.

How many tons for a 16 by 24 low spot and a 30 foot culvert run?

Both figures are hypothetical. Take the regraded low spot first, sixteen by twenty-four feet, finished with an average four inches of sand over prepared ground.

• 16 x 24 = 384 square feet
• 4 inches is 0.333 feet, so 384 x 0.333 = 128 cubic feet
• 128 / 27 = 4.7 cubic yards

This site publishes about 2,700 lb per cubic yard for mason and washed sand, which is 1.35 tons per yard. So 4.7 x 1.35 = 6.3 tons.

Now the bedding around a culvert line, thirty feet long in a three foot wide trench, with six inches of sand under and around the pipe.

• 30 x 3 = 90 square feet
• 6 inches is 0.5 feet, so 90 x 0.5 = 45 cubic feet
• 45 / 27 = 1.7 cubic yards, and 1.7 x 1.35 = 2.3 tons

Note that the trench figure ignores the volume the pipe itself occupies, which makes it a slight over-estimate, and that is the right way round for a bedding job. The sand calculator runs the same arithmetic, handles circles and up to five areas, takes depths in inches and offers a five percent addition.

A mix is the one case where none of this applies: the sand quantity for concrete or mortar comes from the recipe, so get that figure from whoever is batching it. Otherwise, set the amount and the date on this page, and if a hard frost is forecast for that night, plan where a tarp can go over the pile.