Why Your Garage Floor Is Pitting After Winter (and How It Gets Fixed)
The craters and flaking that show up every spring are not bad luck or bad concrete. They are a predictable reaction between road salt, water, and a bare slab.
Garage floor pitting is what happens when road salt and snowmelt soak into bare concrete and then freeze - the trapped water expands, and it pops small flakes and craters off the surface, one cycle at a time. If your Lake County garage looked fine in November and came out of winter pockmarked, that is the mechanism at work. The good news: the slab underneath is almost always healthy, and the surface can be repaired and sealed so it does not happen again. This guide starts with the "why," because understanding what is actually eating the surface is what tells you which repair is worth paying for.
Why bare and sealed concrete pits in the first place
Concrete looks solid, but the surface is full of tiny pores. Every time you pull a car in during winter, brine and slush drip off the tires and undercarriage and settle into those pores. De-icing salt makes it worse two ways: it holds moisture against the concrete longer, and it lets that moisture keep freezing and thawing across a wider temperature range. When the water in the pores freezes, it expands roughly nine percent, and that expansion has to go somewhere - so it pushes the top layer of the surface off. Multiply that by dozens of freeze-thaw cycles between December and March and you get the shallow, chalky pitting that defines a Lake County spring. The Portland Cement Association describes freeze-thaw as one of the main durability threats to exposed concrete, and de-icing salt is the accelerant.
A thin topical sealer slows this down for a while, but it wears off first in the tire tracks - exactly where the brine lands - so the bare lanes start pitting while the edges still look sealed. Whether salt is doing this to your specific floor is worth understanding on its own, which we break down in how road salt wrecks a garage floor.
Read your floor: cause, what you see, and the fix
Not all surface damage is the same, and the right repair depends on how far the freeze-thaw cycle has gone. Match what you see below to figure out where your slab actually stands.
| What caused it | What you see | How it gets fixed |
|---|---|---|
| Early salt-water absorption on bare concrete | Shallow craters, chalky dust, flaking in the tire lanes | Grind the surface, skim-fill the pits, coat to seal |
| Worn topical sealer over the traffic lanes | Pitting concentrated in the wheel paths, edges still smooth | Grind off the failed sealer, patch, apply a bonded system |
| Advanced freeze-thaw (spalling) | Larger sheets or chunks broken away, exposed aggregate | Deeper patching and resurfacing, then full coating |
| Salt pooling at the door line | A band of heavier pitting across the front of the slab | Grind, rebuild the low band, seal the whole floor |
The through-line is the same in every row: grinding creates a clean profile, patching restores the flat surface, and a bonded coating is what stops water and salt from reaching the concrete again. Skip the last step and you are back here next spring.
TL;DR
Pitting is road salt and water soaking into bare concrete and freezing, which pops the surface off flake by flake. The slab is usually fine - only the top is damaged. A pro grinds the surface, fills the pits, and seals it with a polyurea base and polyaspartic topcoat so salt brine has nothing to soak into. Filling the craters alone does not stop it; sealing the surface does.
Floor pitted after this last winter?
We grind, fill, and seal it so salt cannot get back in - free quotes.
How a pro actually repairs a pitted floor
A real repair is three moves in order, and none of them is optional. First, grind. Diamond grinding takes the surface down past the flaking, chalky layer to sound concrete and opens the pores so a coating can bond. This step also flattens the high and low spots the pitting left behind. Second, fill. The craters, spalled patches, and low bands get filled with a polymer-modified patch compound that bonds into the ground profile, then gets ground flush so the finished floor is level. Third, coat. A polyurea base soaks into the freshly ground concrete and locks the repairs down, and a polyaspartic topcoat goes over it as the wear surface. The full step-by-step is covered in fixing a pitted and spalled garage floor, and the service itself lives on our garage floor repair page.
The reason this holds where a bag of patch compound from the hardware store does not is bond and continuity. A DIY skim over a dirty, sealed surface has nothing to grip, so it lifts. A ground-in system becomes part of the floor and covers the whole surface as one film, with no bare lanes left for brine to find.
Why the coating is what actually stops the cycle
Filling the pits fixes what you can see. Sealing the surface fixes what caused it. Bare or patched concrete still drinks salt water, so the freeze-thaw damage simply starts over on the new surface the following winter. A continuous polyurea-and-polyaspartic film changes the physics: there are no open pores for brine to soak into, so salt sits on top and gets mopped up instead of freezing inside the concrete. That is the difference between a repair that lasts one season and one built to shrug off the next decade of salt. The system, and why its flexibility survives freeze-thaw where rigid coatings crack, is the whole reason we lead with it on every install.
If your floor came out of this winter pitted, the fix does not get cheaper or simpler by waiting for the next salt season to deepen it. Request a free quote and we will look at your actual floor, tell you whether it is shallow pitting or real spalling, and walk you through the grind-fill-seal plan for it.