COMPOSITION FOR RENDERING WATER-REPELLENT POROUS INORGANIC BUILDING MATERIALS BY IMPREGNATING

A composition is disclosed which is useful for the water-repellent impregnation of porous mineral building materials. The composition is based on organosilicon compounds which contain alkoxy groups and comprises an emulsion which contains 2.5 to 25% by weight of an alkoxysilane of the formula R1-Si(OR2)3 wherein R1 is an alkyl group with 3 to 12 carbon atoms and R2 is a methyl or ethyl group, 2 to 20% by weight of an alkoxysiloxane of the formula wherein R3 is an alkyl group with 1 to 6 carbon atoms a is 0.8 to 1.2 and b is 0.2 to 1.2, 0.01 to 5% by weight of an emulsifier, 0.01 to 0.1% by weight of fillers with an effective surface area of at least 40 m2/g and 49.9 to 95.48% by weight of water. The composition has a long shelf life and, due to its high penetration, a high water-repellent effect on the surface, as well as deep within, all mineral building materials.