#67 Stone: A Washed 1/4 to 3/4 Inch Aggregate

Almost every order for #67 stone starts as a substitution question. A plan sheet, a county detail or a supplier told someone to use a number, and what the buyer actually wants to know is whether the size either side of it would do the same job. The answer changes with the ground the work is going into: a trench cut through silty river-bottom soil is a different problem from the same trench in glacial sand or in piedmont clay, and the gradation is the part of the design that decides whether the trench is still working in ten years.

So the sensible way to read this page is as a spec sheet with the decision attached to it.

Three specification lines that decide everything else

• Size range: 1/4 inch to 3/4 inch. Small enough to shovel and rake cleanly, large enough to leave real void space between pieces.
• An ASTM gradation. The number is a published size designation rather than a trade name, which is why engineers and inspectors call for it by number.
• No fines in the mix. The material is washed, so there is nothing small enough to clog the gaps. That single property is why it drains and why it will never firm up underfoot.

Set against #57 Stone, which runs roughly 3/16 inch to 1 inch, this size packs slightly tighter, looks finer and is easier to work around a pipe. Set against a blend that carries dust, such as Crusher Run, it is a different category of material entirely: one drains, the other compacts.

Where #67 stone lands on the jobs it is ordered for

What silt, sand and clay do to a trench cut through them

A clean stone keeps working until something fills its voids, and what is available to fill them depends on the soil around it.

Silty ground is the hardest case. Fine particles travel with groundwater and settle in the gaps, and a drain that silts up from the outside in cannot be flushed clean. Sandy ground moves less freely but still migrates over the years. Heavy clay sheds fewer particles but holds water against the trench, so the drain has to carry more flow for longer. In frost country there is a second reason to keep the trench open: water that cannot leave freezes, and the pressure it generates is what pushes walls and footings around over successive winters.

The practical answer in all three cases is separation fabric around the stone, not a different stone.

New lawn ground is where people reach for the wrong product

This size gets ordered for lawn preparation now and then, and it is a poor fit. It holds no nutrients, drains water away from roots rather than to them, and leaves a layer that a mower and a lawn rake will find forever. Top Soil is what a new lawn is graded and seeded into, with Fill Dirt underneath if a low area has to come up first. Keep the clean stone for the drain that stops the lawn sitting wet, which is often the actual problem behind the question.

Cubic yards for a 35 foot drain trench and a 9 by 9 pad

Hypothetical figures. This site's calculator figures #57 and #67 crushed stone at about 2,800 lb per cubic yard, or 1.40 tons per yard, so the tonnages below are approximate; the stone calculator will run the same conversion on your own dimensions.

Drain trench. 35 feet long by 18 inches wide, stone 10 inches deep around the pipe: 1.5 feet wide x 35 = 52.5 square feet. 52.5 x 10 / 12 = 43.75 cubic feet. 43.75 / 27 = 1.62 cubic yards, and 1.62 x 1.40 = about 2.3 tons.

Shed or hot tub pad. 9 by 9 feet at 4 inches: 9 x 9 = 81 square feet. 81 x 4 / 12 = 27 cubic feet, which is exactly 1 cubic yard, or roughly 1.4 tons.

Two coverage figures worth remembering: one cubic yard spread 4 inches deep covers about 81 square feet, and at 2 inches about 162 square feet.

Ordering a clean stone and landing it near the trench

Choose the quantity and the delivery date here on the product page. Delivery is arranged at checkout by ZIP code, and the truck needs a clear route to a spot it can tip on firm ground. For trench work, a drop alongside the run rather than across it saves a great deal of wheelbarrow time, and this size moves easily by shovel because there is no dust in it to stick. If your trench dimensions are awkward or you are working to a detail drawing, send the figures through the contact page and ask for a quote by email.