(Also see Concrete, Smooth Concrete and Exterior Concrete Substrates) Rough concrete will have a surface texture like sandpaper. This type of concrete is typically very porous and requires minimal preparation.
All concrete substrates should be clean, dry and free of dust, dirt, oil, grease, paint, tar, wax, soap, concrete curing compounds, concrete color stains, concrete sealers, clear coats, loosely bonded toppings, any primers that are not MAPEI brand, old adhesive residues (unless otherwise recommended by MAPEI), and any other substance that may prevent, reduce or affect adhesion or performance.