What a garage floor has to survive
A garage floor takes a beating that most interior floors never see. Tires bring in water, grit and, in winter, road salt or brine. Hot tires sit on the same spots every day. Motor oil, brake fluid, coolant and gasoline drip and get tracked around. Sunlight comes through the open door and hits the same section of floor for years. A coating that handles all of that is a multi-layer system, not a single coat of paint.
The usual system, layer by layer
- Mechanical preparation. The concrete is ground with diamond tooling (or, on some jobs, shot-blasted) to remove the weak top layer, sealers and contamination, and to leave a profile the primer can grip. See our prep guide for why acid etching isn't a substitute.
- Crack and joint repair. Cracks and spalls are cut open, cleaned and filled, then ground flush so they don't telegraph through.
- Primer or basecoat. Usually an epoxy, chosen for adhesion and, where the moisture test calls for it, a product made to tolerate moisture coming up through the slab.
- Broadcast. Decorative vinyl flake or colored quartz is scattered into the wet basecoat. A full broadcast, where the floor is covered until no more will stick, gives texture, hides dust and small imperfections, and adds body to the system.
- Topcoat. A clear coat, often polyaspartic or polyurethane, that takes the wear, resists chemicals and, unlike most epoxies, holds up in sunlight.
Hot-tire pickup
Tires get hot on the road, and when a hot tire sits on a coating, it can soften and grab the surface. When the car backs out, a weak or poorly bonded coating can lift with it. The defenses are the same things that make any coating last: a properly profiled and clean slab, a primer that has really gripped the concrete, enough total film build, and a topcoat with good hot-tire resistance on its data sheet. Ask the specialist which products they'll use and look at those data sheets yourself.
Fluids and chemicals
Most coatings resist motor oil and brake fluid well once fully cured, but resistance varies by product and some chemicals stain even when they don't damage. The product's data sheet should list chemical resistance. Wipe up spills promptly rather than leaving them for days; see our floor care guide.
Traction
A smooth clear coat can be slippery when wet. Broadcast flake or quartz adds texture, and many topcoats can take an anti-slip additive. Tell the specialist who uses the garage: children, older relatives, anyone who walks in from the rain. More texture means more grip but slightly harder cleaning.
Cure time and getting your garage back
Different chemistries cure at different speeds, and temperature and humidity change those speeds a lot. The specialist should tell you, in writing, when you can walk on the floor and when you can drive on it. Be wary of any promise that a damaged or damp slab can be ground, repaired, moisture-treated and fully cured in a few hours: on a slab like that, rushing the steps is how coatings end up peeling.
Questions to ask
- How will you prepare the concrete, and what profile are you aiming for?
- How will you test the slab for moisture, and what will you do if the result is high?
- Which primer, basecoat and topcoat will you use? Can I see the data sheets?
- How many coats, and how thick will the finished system be?
- When can I walk on it, and when can I park on it?
- What does the written warranty cover, and what voids it?