Breaker Run: the Layer You Argue About Before You Dig

Nobody orders this material because they like the look of it. They order it because something on the property sank, spread or went soft during the thaw, and the fix has to go underneath rather than on top. That is the real decision behind a load of Breaker Run: not which stone looks best in the pile, but how much of the build you are willing to bury.

The spec is short, and the size in it is bigger than most people picture. WisDOT Standard Specifications Section 311 defines breaker run as stone or concrete taken through a primary crusher set to produce material predominantly 6 inches or less in at least one dimension, not further screened or crushed. So the pile holds slabs and chunks up to about the size of a dinner plate, everything the crusher made on the way down, and dust. That whole range, top size and fines together, is what separates it from three other products that look close to it in a photograph.

The three products people nearly buy instead of this one

• 3/4" Traffic Bond is the dense graded base that goes directly under a driving surface. If the layer you are building is the one tires will ride on, that is the product. Breaker Run goes under it, not in place of it.
• #4 Crushed Stone runs about 3/4 to 1-1/2 inches, screened to that band with the fines taken out, so the gaps between the pieces stay open. It is the coarse lift to reach for when the layer also has to let water through.
• 3/4" Crushed Stone, the clear stone with the fines screened out, drains hard and never packs. It belongs in a trench or against a foundation.
• Screenings at 1/4 inch minus level and bed. They do not carry.

Breaker Run is the coarsest of the four and the only one designed to be buried. The big broken pieces bridge ground too soft to hold a graded base, the unscreened fines wedge in around them, and the layer tightens under a roller instead of shifting. Nothing rides on it directly.

What a correction layer fixes on till, lake clay and outwash

Frost runs at least 48 inches deep under a footing here, and 48 to 72 inches under pavement by late winter. The damage shows up on the way back out.

• The surface thaws while the subsoil below is still frozen, so meltwater has nowhere to drain and sits in the top few inches.
• Reddish lake clays around Green Bay, Lake Winnebago and the Fox Valley hold that water for weeks. A pad built straight on unimproved clay presses down into it.
• Northwoods till is mixed: stony sandy loam on the rises, peat and muck in the hollows. The hollows are where a thin build disappears.
• Central Sands outwash drains fast once frost leaves, so the layer there is usually thinner, though low ground in the old lake bed stays soft long after the rest of the site.
• Driftless silt loam over sandstone and dolomite softens on grade and ruts under a single machine pass.

Subgrade correction is the job WisDOT puts this material to, and it is the job it does on a property as well: a thick rolled layer of coarse unscreened stone spreads a load across ground that would otherwise let one wheel or one corner of a footing press straight through.

Why the top size decides how thick the layer has to be

A layer has to be deep enough to hold the largest pieces in it and still have material packed around them, so a 6 inch top size rules out anything thin. Four inches of Breaker Run is a single course of loose rock with nothing bedding it, and a roller will not bring it to grade.

• Treat about 8 inches as the shallowest placement worth making, and a foot or more where the subgrade is genuinely soft.
• On reddish lake clay or in a muck hollow, add depth rather than hoping. On sandy outwash you can usually take some back.
• Strip sod and topsoil first in every case. Organic material under a base keeps settling for years.
• A machine track across a yard being prepped for a new lawn is the one job this material does on its own, because nothing on it has to finish flat. Depth there is about keeping a skid steer off wet subgrade.
• A hot tub pad or a side-yard dog run is a different build. Those need a dense graded layer that finishes tight and level, which is 3/4" Traffic Bond, with Breaker Run underneath only where the ground below will not carry it.

Wetting it, rolling it in thick lifts and beating the freeze-up

• Shape the subgrade to the fall you want the finished surface to hold. The layer copies whatever shape you give it.
• Place it in lifts and compact each one, but keep every lift thick enough to bury the biggest pieces. Lifts of a few inches do not work with stone this size.
• Dampen the material before packing. Dry fines will not travel into the gaps between the angular pieces, and saturated material pumps instead of tightening.
• A plate compactor is the wrong machine here. It rides over pieces this size rather than seating them, so a roller does the work whatever the size of the job.
• Frozen ground stops compaction, so this work runs from the end of the thaw into late fall. Class II state highways and posted county, town and village roads also carry spring weight limits while frost is coming out.

Tons for a soft lane, a shed apron and a muck hollow

Length times width, times depth in inches divided by 12, divided by 27 for cubic yards. The only weight this site publishes for the crusher run and road base family is roughly 3,000 lb per cubic yard, about 1.50 tons per yard, so tonnage is the yardage times 1.5. That row describes a dense graded base and Breaker Run is not one, so read the tons as an approximation and check them against the ticket. These are hypothetical jobs.

• Soft stretch of field lane, 14 ft wide by 75 ft long at 10 inches: 1,050 sq ft x 0.833 = 875 cubic feet. 875 divided by 27 = 32.4 cubic yards, or about 48.6 tons.
• Pole shed apron, 24 ft by 32 ft at 8 inches: 768 sq ft x 0.667 = 512 cubic feet. 512 divided by 27 = 19.0 cubic yards, or about 28.4 tons.
• Muck hollow under a new pad, 18 ft by 22 ft at 18 inches: 396 sq ft x 1.5 = 594 cubic feet. 594 divided by 27 = 22.0 cubic yards, or about 33.0 tons.

Those are loose volumes. The layer loses height as it packs, so order to the measured depth and expect the finished surface to sit lower than the string line. Whatever caps it is a second calculation with its own depth and its own product. The Crusher Run Calculator runs the same arithmetic if you would rather check it than do it.

Set a quantity and a delivery date on this page. Delivery is arranged at checkout from your ZIP code, so walk the route in first and pick a drop a loaded tandem can reach and back out of without crossing soft lawn.