Crusher Run, Ordered When a Lane Was Never Given a Base

The mistake this material gets bought to fix is loose stone on soft ground. Somebody tipped a few loads of round gravel on a lane over the years, the wheels pushed it apart, and by the second mud season it was back in the till.

Crusher run is the other approach. It is meant to be compacted into a layer, not scattered on top of one.

Three quarter inch minus: what crusher run is once it is tipped out

Size is 3/4 inch minus. The blend is crushed stone with stone dust and fine particles through it, and the stone is angular rather than rounded.

Those two facts are the whole product. The angular faces lock against each other instead of rolling. The fines fill the spaces between them during compaction, and with a little moisture they bind the larger stone into one cohesive layer.

That binding is also the limitation. Fines in the mix mean water moves through it slowly. This is a base material, not a drainage stone.

Where it belongs, and at what depth

Where it does not belong: the finished driving surface. Fines at the surface turn to a skin of mud in a wet week and to dust in a dry one. Keep a wearing course over it.

Ledge, frost heaves and the lane in mud season

Granite ledge sits close to grade across much of this state, and frost reaches roughly 48 inches in the south, 60 or more in the North Country. No base layer goes below that.

What a compacted layer does is give the heave something to lift as a unit. A lane with a bound base comes up in spring and settles back roughly where it was. A lane of loose stone comes up in pieces and stays that way.

The other half of the job is water. In mud season, thawed ground holds water above soil that is still frozen, so the base sits in it. Crown the lane so water leaves sideways, and ditch both shoulders. On dense till the ditch matters more than the extra inch of stone.

Work between the end of mud season and the fall freeze. Frozen ground does not compact, and a load spread on saturated April ground is a load you spend again.

Damp it, then pack it

Spread in lifts of three inches or so. Wet the surface lightly before the compactor goes over it, damp through rather than puddled.

A plate compactor is enough for a pad or a path. A lane wants a vibratory roller, or failing that a loaded truck driven up and back in overlapping passes until the tires stop leaving a mark.

Expect the layer to lose height as it packs. Spread a little proud of your finished grade and let the machine bring it down.

Yardage for a boat pad, 400 feet of lane and a garden path

Three hypothetical jobs. Crusher run runs about 3,000 lb per cubic yard on this site's published figures, near enough to 1.50 tons per yard, so the tonnages below are approximate. Take other shapes and depths from the crusher run calculator.

RV or boat parking pad, 12 ft by 35 ft, 6 inches

• 12 x 35 = 420 sq ft
• 420 x 6 / 12 = 210 cu ft
• 210 / 27 = 7.78 cu yd
• 7.78 x 1.50 = 11.7 tons

Long rural lane, 400 ft by 10 ft, 4 inches

• 400 x 10 = 4,000 sq ft
• 4,000 x 4 / 12 = 1,333 cu ft
• 1,333 / 27 = 49.4 cu yd
• 49.4 x 1.50 = 74.1 tons

That is a staged job. Do it in runs you can spread and compact before you stop for the night, working from the far end back toward the road.

Garden path, 60 ft by 3 ft, 3 inches

• 60 x 3 = 180 sq ft
• 180 x 3 / 12 = 45 cu ft
• 45 / 27 = 1.67 cu yd
• 1.67 x 1.50 = 2.5 tons

Add a little for the edges you will trim wider than planned.

Clearing a dump spot before the truck turns in

Pick the spot before the delivery date, not on the morning. It wants firm ground, room for the truck to back, and clear height overhead for the body to come up. Camp-road branches and a low wire are the two things that turn a delivery around.

Put the pile as close to the work as the ground allows, but not on a lawn you care about or on the run you are about to build. Stone is easier to move downhill than up.

Set the quantity and the date on this page. Delivery is arranged at checkout by ZIP code. If you are unsure whether the lane wants this or crushed gravel under it, put the question to New Hampshire Rock Supply through the contact page first.