Q.: We're placing a concrete floor that will later receive a light-reflective polyurethane coating. Specs require a 1- or 2-mil rough finish. What does that mean? Do we just magnesium float it, give it a sweat trowel finish, or what?

A.: Give the floor a normal steel trowel finish. Urethane coatings have hardly any build. Even with three coats (primer, film build, and finish) the total thickness won't exceed 6 mils (0.006 inch). Thus the coating doesn't alter the finish you provide.