Concrete Leveling in Superior, WI

Red clay is the Superior story

Duluth is hillside and rock; Superior is flat and clay. Douglas County's red lacustrine clay — deposited by glacial Lake Duluth — is the defining soil of this side of the harbor, and it behaves nothing like the hillside soils a few miles north. It's expansive: it swells when wet and shrinks when dry, and it drains very poorly. That shrink-swell movement is textbook slab settlement soil even before frost enters the picture.

Add frost. The whole region runs roughly 42 freeze-thaw cycles a year and receives about 90 inches of snow. On a flat Superior lot, meltwater has nowhere to go — it can't drain down through clay and it can't run off a lot with almost no fall. It sits in the top foot of soil, freezes, lifts the slab, and leaves the clay softer than it found it. The classic result here is a driveway or walk that has settled fairly uniformly rather than tipping — the whole thing simply sank into the clay.

Housing from the boom years

Superior's residential core dates largely to the 1888–1892 boom, when the city exploded alongside the ore and grain trade. Concrete on those properties — front walks, alley aprons, basement floors added later — has been through well over a century of clay movement. Around Billings Park and the older east-end streets we regularly see original walks that have settled below the grass line, and stoops that now tip back toward the house.

That last one matters here more than most places. A stoop or patio tipping toward a foundation on clay soil delivers water to a wall that already has poorly-draining soil against it. Correcting the pitch is often the most valuable part of the job.

Where we work

The whole city, from the neighborhoods near Wisconsin Point and Barker's Island through Billings Park, the North End, and the newer subdivisions on the south side. The SS Meteor sits a short drive from a good share of the driveways we're asked to look at. Because Superior is minutes from Duluth over either bridge, there's no travel surcharge — we treat it as home territory.

What we do here most

Two jobs dominate on this side of the harbor: driveway and garage apron lifting, where slabs have sunk into soft clay and the apron has dropped away from the garage slab; and sidewalk and front step leveling on the older boom-era blocks, where a century-old walk has settled into a series of trip hazards.

On expansive clay we frequently lean toward polyurethane foam rather than slurry, simply because adding weight to soil that already couldn't carry the slab is working against yourself. We'll explain the trade-off on site, including cost — foam runs more per square foot.

New to why any of this is happening? Start with our frost heave guide, or head back to the main concrete leveling page.