#57 Stone in Wisconsin: Open Drainage Stone for Thaw-Season Work

Every drainage problem on a Wisconsin property announces itself in the same two weeks: the surface thaws, the subsoil underneath is still frozen, and water that has nowhere to go stands in the exact spots you had forgotten about since last March. That is when #57 stone gets ordered, and it is also the stretch when the ground is least willing to let you install it. Knowing which side of that window you are on decides how the job goes.

Construction entrances, and why the order lands before the frost is out

The single job this stone gets bought for most around here is a stable entrance onto a site that is about to turn to soup.

• Angular 3/16 to 1 inch pieces knit together under a wheel instead of rolling apart the way rounded gravel does.
• The voids between pieces take mud off tires rather than smearing it out onto the town road.
• Water moves through the layer instead of collecting in it, which matters on a site where the subgrade will not drain until May.
• The same load does double duty later as trench stone or backfill once the entrance comes out.

Class II state highways and posted county, town and village roads carry spring weight limits while frost is coming out, so entrance work and site access tend to be planned around that calendar rather than against it.

How angular stone behaves on Fox Valley clay and Central Sands outwash

The material is consistent. The ground under it is not.

• Lake clays around Green Bay, Lake Winnebago and the Fox Valley are tight and slow. Stone dropped straight onto wet clay gets pressed into it and disappears, which is why a separation layer earns its cost there.
• Central Sands outwash drains fast once thawed, so an open stone layer mostly needs protecting from the sand migrating up into it.
• Northwoods till is mixed: sandy and stony on the rises, peat and muck in the hollows. The hollows are where stone vanishes.
• Driftless silt loam over shallow dolomite runs water off the ridge fast and then loses it into cracks and springs lower down. Trench routes there need to follow where the water actually goes, not where the site plan says it should.

Freeze-thaw is the constant. Open stone gives water somewhere to sit and move that is not the underside of a slab, a footing or a wall.

Trench, fabric, and the mistake that plugs the voids

The stone only works while the spaces between the pieces stay empty. Most failed drains failed for that one reason.

• Line the trench with a separation fabric before the stone goes in, and wrap it over the top before backfill. Soil migrating into an unlined trench chokes it within a few seasons.
• Bed and surround perforated tile fully. At 3/16 to 1 inch the pieces are far too large to drop through the slots of a standard 4 inch line, so the pipe stays clear.
• Give the run a continuous fall to a daylight outlet, a sump or a ditch. A level trench full of open stone is a storage tank.
• Behind a retaining wall, keep the stone column against the back of the wall and carry it down to a drain line so water leaves rather than pushing.
• Keep it clear of topsoil at the top of the profile. If the finished grade sheds silt into the stone, you have built a filter, not a drain.

#67 Stone and 3/4" Crushed Stone next to #57 Stone

Three products on this site look similar in a photograph and behave differently in a trench.

They are separate products sold under separate names, so order by the name on the page rather than assuming one substitutes for another on a spec. If the job needs a layer that packs hard instead of draining, the material you actually want is 3/4" Traffic Bond.

Working out the load for an entrance, a patio bed and a creek run

Length times width times depth in inches divided by 12, then divided by 27 for cubic yards.

• Example, a construction entrance 12 ft wide and 50 ft long at 8 inches: 12 x 50 x 0.667 = 400 cubic feet, divided by 27 = 14.8 cubic yards.
• Example, an open bed under a 14 ft by 16 ft permeable paver patio at 4 inches: 224 square feet x 0.333 = 74.7 cubic feet, divided by 27 = 2.8 cubic yards.
• Example, a dry creek run 30 ft long and 4 ft wide at 6 inches: 30 x 4 x 0.5 = 60 cubic feet, divided by 27 = 2.2 cubic yards.

This site's calculators put #57 crushed stone at about 2,800 lb per cubic yard, roughly 1.40 tons per yard, so the weights are approximate. That makes the entrance 14.8 x 1.40 = about 20.7 tons, the paver bed 2.8 x 1.40 = about 3.9 tons and the creek run 2.2 x 1.40 = about 3.1 tons.

Open-graded stone does not compact down the way a dense base does, so what you order is close to what you end up looking at. Round the trench figure up rather than down, because a short load on a dug trench means leaving it open. The calculator turns those cubic yards into tons for this material.

Pick a quantity and a delivery date on this page. Delivery gets arranged at checkout from your ZIP code, so have a dump spot in mind that a loaded truck can reach and back out of cleanly.