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These paints which have largely superseded the simple Cement washes are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.
