AP PREP ETCH is a low odour, environmentally friendly safe etch for use on concrete surfaces to obtain a surface profile for optimum adhesion. This is done by chemically reacting with surface laitance to give a slightly etched finish to the surface. A safer alternative to hydrochloric acid etches. Safe near plants and grass. Dissolve in water. AP PREP ETCH is used on concrete floors, driveways, garage floors, steps and all concrete drive-on and walk-on surfaces to ensure a surface profile that provides maximum adhesion of appropriate finishing systems. Can also be used to reduce the effects of efflorescence salts. There is no benefit for use on previously coated floors.