Screenings in Maryland: Stone Dust for Bedding and Packed Paths

Take a handful out of the pile and squeeze it. Damp screenings hold the shape of your fist for a second before crumbling, and that is the whole product in one gesture. The pile looks less like stone than like coarse gray grit, angular under a thumbnail, with the finest material sifting to the bottom when the truck tips. Dry, it powders and blows; wet, it packs. Most Maryland yards call it stone dust, and what it does on your site depends almost entirely on how wet it is on the day you spread it.

Why a stone dust job waits for spring in Garrett County and starts earlier on the Shore

Screenings only earn their keep when they are compacted, and compaction needs ground that is neither frozen nor saturated. That gives a working season, and the season is not the same length across the state.

Aiming for the shoulders of that window is usually a mistake. A bed compacted onto ground that is still giving up winter water settles unevenly once it dries out, and pavers set on it rock by midsummer.

Getting the base ready in the weeks before the screenings arrive

Screenings are the top layer of a build, never the whole of it. Underneath belongs a compacted base: CR-6 on a patio or walk, Crusher Run where a yard has it to hand. Using screenings as the entire support layer is the most common patio mistake in this state, and it shows up as a dished center after the first winter.

Before the load lands, the base should be shaped, compacted and already falling away from the house at roughly a quarter inch per foot. Edge restraint goes in before bedding, not after. And on Piedmont silt or low Coastal Plain ground, check that the subgrade is dry enough to take a plate compactor without pumping water to the surface. If it pumps, wait.

Paver beds, flagstone joints and the packed walk to the shed

• A setting bed for pavers, brick or flagstone, screeded thin and level so each unit beds evenly instead of rocking on a coarse layer.
• Joint filling between flagstone or pavers, swept in and watered so the units hold together and weeds have less room.
• Leveling a subgrade under a shed floor, a hot tub platform or a concrete pour, where fine material fills the shallow dips a coarser stone bridges over.
• A compacted path surface for a garden walk or service route, which once watered and tamped will take a garden cart or a wheelchair.

What it will not do is drain. Screenings are the opposite of a washed stone: they are the fines that washing removes. Put them where water has to travel and they seal.

Yardage for a foundation trench, a settled patio corner and a culvert apron

Square feet times depth in feet gives cubic feet; divide by 27 for cubic yards; multiply by 1.45 to reach tons at the site's approximate figure of 2,900 lb per cubic yard for screenings. These are worked examples, not jobs anyone has done.

• A French drain along a foundation, 40 feet of trench, 12 inches wide and 18 inches deep: 1 x 1.5 = 1.5 cubic feet per foot of run, so 40 x 1.5 = 60 cubic feet. 60 divided by 27 = 2.22 cubic yards. Order that volume as washed stone rather than screenings. #57 Stone or Drain Rock keeps its voids; stone dust in a drain trench will pack and stop it.
• A settled corner of a patio being reset, 22 feet by 14 feet brought back to grade at an average 2 inches: 22 x 14 = 308 square feet. 2 inches is 0.1667 feet, so 308 x 0.1667 = 51.3 cubic feet. 51.3 divided by 27 = 1.9 cubic yards, about 2.8 tons. This one is screenings, over a base that has been re-compacted first.
• A culvert outlet or ditch lining, 12 feet long by 6 feet wide at 6 inches: 12 x 6 = 72 square feet. 6 inches is 0.5 feet, so 72 x 0.5 = 36 cubic feet, divided by 27 = 1.33 cubic yards. Take that volume to RipRap instead. Moving water lifts fines out in a single storm.

For a bedding layer the volume is small and the accuracy matters more than the total, so run the measurements through the stone calculator before you settle on a number.

The first winter: joints that drop, edges that creep, dust that travels

A compacted screenings path tightens over its first few months and then needs very little. Expect three things all the same. Swept joints drop a few millimeters after the first heavy rain and want topping up once. The outer six inches of a path will creep if there is nothing holding it, so an edge restraint pays for itself. And in a dry August the surface gives off dust that tracks indoors, which is an argument for keeping it to paths rather than the area right outside a back door.

Freeze and thaw is the real test. Water held in a bedding layer over a base that does not drain is what heaves paver work in this climate, and it is why the base below matters more than the two inches of grit above it. Where a patio sits on clay that holds water, fix the drainage in the base year rather than hoping a finer bed will make up for it.

Measure the area, take the cubic yards through the calculator, then choose an amount and a delivery date here. If the job is a mix of bedding and joint filling and you are not sure how to split the order, email the dimensions through contact first.