This is the garage of a two-year-old condominium in Rochester Hills, Michigan. The customer wanted a nice-looking flooring system to match the walls and make the floor easy to clean. The photo above left shows the condition of the concrete at the outset of the project. Above right, you can see the concrete once it has been ground clean.
The concrete wasn't extremely dirty after only two years, but it was becoming unstable. Above left, you can see the initial spalling, crumbling and cracking of the concrete near the front of the garage. We made repairs to those areas (above right) and filled the saw-cuts and control joints with polyurea joint filler.
Next, we ground the repairs flush with the concrete, as shown in the above two photos. On the right, you can see a closeup of the work we did on the isolation joint at the front of the garage. We had to make the concrete there stable enough to support the weight of a vehicle but the joint flexible enough that the new flooring wouldn't crack.
We then tested for moisture in the concrete using test methods ASTM F1869 and ASTM F2659. We found the concrete was damp and not drying out. To resolve this problem, we applied 2 coats of a moisture barrier primer (above left and right). This excess moisture turned out to be the cause of the damage to the concrete at the front of the garage.
With the concrete now clean, stable and dry, we installed the gray mix, vinyl color chip system from Citadel Rustoleum chosen by the homeowner. Unlike most garage flooring, this system uses polyurea - not epoxy. Polyurea is 20x stronger than epoxy, lasts much longer, and is more chemical resistant and easier to clean.
We always extend the garage floor coating underneath the garage door to the edge of the driveway. Epoxy yellows over time from sunlight, though, so if a polyurea system isn't being used, that exterior strip will discolor. The strip also has to be protected until dry. We set up plastic sheeting overnight to protect from insects, debris, and rain.