Thornton Foam Leveling

A settled slab is a story about dirt, not about concrete. Something below compressed, washed away, or was never compacted properly to begin with, and the slab followed it down. So the useful question isn't how far it dropped. It's what occupies that space now, and what put it there.

Polyurethane is good at answering that. The resin enters through a port about the width of a pencil, travels as a liquid, then expands and hardens right where the hollow is. It reaches irregular pockets a heavier material would bridge straight over, it weighs a small fraction of what cement grout weighs, and it's rigid enough to carry the slab within minutes. On ground that has already failed once, adding almost nothing back is the whole argument.

What's actually underneath a Thornton slab

Start with the clay. Adams County soil holds water, changes volume as moisture comes and goes, and does most of the work that ends with concrete out of level. But the clay usually isn't the hollow itself. The hollow forms in whatever sits between that clay and the bottom of your slab.

In Eastlake, that layer is frequently nothing at all. Older flatwork here went straight onto graded soil, so when a moisture cycle pulls the surface down half an inch, the slab loses its bearing and a pocket opens under it. Hunters Glen and Quail Valley usually have some base, but plenty of it went in thin and it went in before anyone thought carefully about where roof water would land. Twenty years of a downspout dumping at one corner will strip the fines out of four inches of road base without any trouble at all.

North Creek Farms and the newer construction north of it have a different underside: trench spoil. Sewer, water, and electrical laterals got backfilled, sometimes in lifts too deep to compact honestly, and that soil keeps consolidating for years. The slab above a trench line settles in a stripe, which is a pattern you can't unsee once somebody points it out.

Drainage decides whether the lift stays put

We can fill any hollow you've got. What we can't do from the hose is stop the water that dug it. So before we price a lift we walk the property hunting for the supply: downspouts letting go right on the concrete, grade that slopes back toward the house, a sprinkler zone that has been watering a walkway for years, a window well that overflows, edge joints that haven't held sealant since the slab was young.

Fix those and a resin lift is effectively permanent, because polyurethane doesn't wash out, doesn't rot, and doesn't compress under load. Skip them and you've bought time rather than a fix. We'd sooner say that during the estimate than have the conversation two winters later.

Something else about our ground up here. Shallow soil moisture moves constantly and the freeze-thaw count is high, so any pocket under a slab gets worked all winter long. Water finds it, freezes, pushes, thaws, drains away leaving the space slightly bigger than before. That's why a hollow that took a decade to form can double in one wet year.

Where the water came from, and how we cut it off

How an injection morning runs

• Sound the panel and mark the hollow so ports land where the space is
• Locate irrigation and low-voltage lines before a bit touches concrete
• Drill 5/8-inch ports on a grid tight enough to keep the rise even
• Inject in short bursts, watching the slab with a laser instead of the pump gauge
• Stop the moment it reads level, because chasing one more eighth of an inch cracks concrete
• Patch every port flush and clean the surface down
• Walk it with you, then talk through the drainage work that keeps it there