Crack Filling in Saint Paul, MN

Crack filling means sealing open cracks with hot-pour rubberized material so water cannot run through the pavement into the base, and in Saint Paul it matters because the thaw, not the deep cold, does the damage. The airport normals show nearly 18 freeze-thaw days in an average March and about 15 in November, against only about 8 in January, when the pavement mostly stays frozen. In those shoulder months meltwater sits in every open crack by afternoon and freezes again overnight. Filling is cheap next to what it prevents, and it has to happen before any driveway sealcoating, because sealer is far too thin to bridge a real crack.

The material is the point. Hot-pour crack sealant is a rubberized asphalt heated in a kettle and wanded or poured into a clean, dry crack, where it cools into a flexible band that stretches as the pavement contracts in January and squeezes as it expands in July. Cold-pour products from a jug or tube are easier to handle and suit hairlines, but on wide, moving cracks they generally do not last as long. Whatever the product, the crack has to be blown clean first, since filler poured over sand and dust peels out by spring.

Some crews rout before filling, cutting a clean reservoir along the crack so the filler has a uniform depth and two solid walls to grip. Roseville's street crews do exactly that each year on their mill-and-overlay streets, opening a three-quarter-inch by three-quarter-inch groove, blowing it clean and filling it. On a driveway, routing earns its cost on long, straight cracks and on the seam along a garage slab; across a web of small cracks it mostly adds labor.

The ground under a crack decides what the water does next. Much of Saint Paul sits on outwash soils the USDA rates somewhat excessively or excessively drained, so water passing through a crack tends to keep going down through the base. Where a pad sits on the silty Waukegan cap, or on old fill, it lingers, and silt is the kind of soil that heaves when it freezes. Either way the base is weakest while it thaws, which is exactly when the most water is getting in. Crack repair keeps that water on top of the pavement, where it can run off.

Filled cracks are not permanent. Rubberized filler weathers, pulls away from one wall and gets nicked by blades, so a well-kept drive gets a walk-around every spring and touch-ups wherever the band has split. Prices usually run per linear foot, with a minimum charge on small jobs; the cost page lists the observed range and explains how minimums affect a short alley pad.