Water Repellent Cement Paint

Abstract

Water Repellent Cement is a Paint based on Portland Cement with the addition of pigments, fillers, accelerators and water repellent substances. These paints which have largely superseded the simple Cement washes are supplied as a dry powder and mixed with water before use, but for darker colours ordinary cement could be substituted as base. For external faced decoration lighter colour paints are in general preferred, because the colour is matchless conspicuously affected by the formation of sporadic ‘Fade’ films of calcium carbonate over the surface. Cement paints are used externally to prevent rain penetration, as well as for decorative purposes, and can retain some water roofing qualities for as long as ten years on vertical surfaces. For making different colours cement paints a certain percentage of pigments is used in the base cement paint. The pigments must be lime free and the hydrated lime should not exceed 8% of unhydrated CaO and MgO.