Patent ID: 7026013

Claim:
A process for making a porous mineral building material water-repellent, this process comprising the steps of: a) applying to said material a water-repellent liquid silicone composition comprising at least 50% by weight of a cyclic polyorganosiloxane bearing units: or of a linear (POS) (I) having said units, of formula (I): wherein: the radicals R 1 are identical to or different than each other and each represent an alkyl, an aryl, an arylalkyl or Y; the radicals R 2 are identical to or different than each other and each represent an alkyl, an aryl or an arylalkyl; the radical R 3 represents an alkyl, an aryl, an arylalkyl or Y; the radical Y is a functional radical carrying at least one epoxy unit; a and b are chosen such that: 1≦ a+b≦ 1 000 and 1/1 000≦ b /( a+b )<1 if b equals to 0, at least one of the radicals R 1 on each of the two terminal Si atoms of the POS of formula (I) represents Y, said cyclic or linear POS being capable by itself of crosslinking as soon as it comes into contact with the building material and or of reacting with said building material to bind thereto. b) impregnating and penetrating said composition into said material, and c) crosslinking and/or reacting said POS with said material, leading to the formation of bonds between the POS and the material.