Can my pitted, spalling, cracked garage floor be saved?

Know what you are actually looking at

Spalling is the top surface of the concrete breaking away in flakes or sheets, usually starting at the apron or anywhere salt water sits. Caused by freeze-thaw and de-icing salt. Repairable.

Popouts are small conical craters where a piece of aggregate near the surface absorbed water, froze and blew the concrete above it off. Cosmetic. Repairable.

Scaling is a wider, shallower loss of the surface paste, leaving an exposed sandy texture. Common on slabs that were finished badly or got rained on while green. Repairable.

Hairline and shrinkage cracks are from the slab curing, not from failure. Repairable, and extremely common.

Settlement cracks are wider, often with one side sitting lower than the other. These mean the ground under part of the slab moved. Repairable as a surface, but the movement can continue and the crack can telegraph back through. We will tell you that before we start.

Structural failure is a slab broken into moving sections, heaved several inches, or sinking against a foundation wall. This is the one case where a coating is the wrong purchase and you need a concrete contractor first. It is rare.

What repair actually involves

1. Grind the whole floor. Diamond grinding takes off the weak, loose and contaminated surface layer and gets down to sound concrete. On a spalled or scaled floor, this alone removes most of the problem.
2. Chase and fill cracks. Cracks get opened out so the filler has something to key into, then filled with a rigid polyurea or epoxy filler that cures harder than the concrete, then ground flush.
3. Fill popouts and spalled areas. Same material, feathered so there is no lip under the coating.
4. Treat control joints. A joint is there to let the slab move. Filling it solid can force the slab to crack somewhere else instead. Joints get a flexible fill or are honored and carried through the coating depending on the floor, and that is a judgment call made on site.
5. Rebuild the apron edge if the front lip has broken down, which it usually has.
6. Then the coating goes on, and the flake hides whatever minor texture variation is left.

Why flake is the right finish for a rough slab

A solid color coating is unforgiving. Every patch, every repair line and every slight contour shows through because there is nothing to break up the eye. A full flake broadcast puts thousands of chips of three or four colors across the whole floor, and the result reads as texture rather than as patched concrete. On an old slab, the heavier the flake, the better it looks.

When replacement is the honest answer

• Sections of slab moving independently at a crack, with a visible height difference you can catch a boot on
• Heaving, usually from frost or a tree root
• A slab so deteriorated that grinding exposes loose aggregate across most of the floor
• Active water coming up through a crack, which is a drainage problem that has to be solved before anything is sealed over it

If we see one of those we say so. We would rather lose the job than coat a floor that is going to make a liar out of us in two years.

Get my free quote  See our pricing