Abstract: A storage-stable composition adapted for imparting water-repellent properties to masonry materials comprises an aqueous emulsion which defines a continuous aqueous phase and a discontinuous organosilicon phase. The emulsion is formulated from components comprising: (A) a water-insoluble alkoxysilane of the average general formula R.sub.n --Si--R'.sub.(4-n) wherein n is a number from 1 to 2, R is a C.sub.5 -C.sub.20 monovalent hydrocarbon radical and R' is a C.sub.1 -C.sub.4 alkoxy group; (B) a hydrogen-functional polysiloxane having at least two silicon-bonded hydrogen atoms per molecule, at least five siloxy units per molecule and a kinematic viscosity between about 0.5.times.10.sup.-6 and 1,000.times.10.sup.-6 m.sup.2 /sec at 25.degree. C.; (C) an emulsifier; and (D) water. The discontinuous organosilicon phase comprises components (A) and (B) and the continuous aqueous phase comprising said water.