Flat grey concrete gets a different product and a different method. We apply a mineral-based penetrating sealer that soaks into the surface instead of forming a film.

Because it penetrates, spraying is the correct application here, and it changes nothing you can see or feel: same color, same finish, same traction.What changes is what the concrete absorbs. 

Water and chemicals, including the de-icer that drips off your car all winter, bead and shed instead of soaking in. That slows spalling and pop-outs and protects the surface through freeze-thaw season.