Removing paint from concrete can be a troublesome project. Concrete is porous and rough, creating a textured surface to which paint easily adheres. Muriatic acid works very well at removing stains and paint from concrete, but can etch the surface if it is left on for too long or proportioned incorrectly. Muriatic acid will damage skin and clothes, so wear protective equipment at all times and work in well-ventilated areas.
Things You'll Need
Hard-bristled brush or broom
Mix a solution of 1 part muriatic acid to 8 parts water in a bucket. Pour the acid into the water to avoid splashing the undiluted acid.
Pour the solution over the painted or stained concrete surface.
Scrub the surface with a hard-bristled broom or brush to remove the paint and any other stains.
Rinse thoroughly with clean water to remove any acid.
Repeat the process as necessary.
Multiple coats of paint will not be easily removed by the acid. A floor scrubber and screen-mesh sandpaper will effectively sand any concrete surface, removing paint and smoothing the surface of the concrete.
Wear heavy, acid-resistant gloves and boots and a respirator when working with muriatic acid.