Abstract: Method for impregnating mineral building materials, with aqueous solutions of silanols and/or siloxanols is disclosed. The solution is obtained by continuous hydrolysis of alkoxysilanes and/or alkoxysiloxanes, of the general formula ##EQU1## wherein R.sup.1 =alkyl with 1 to 8 carbon atoms, at least 90% of the R.sup.1 groups in the average molecule being alkyl groups with 1 to 4 carbon atoms,R.sup.2 =methyl or ethyl,a=0 to 1.5,b=1.0 to 4.0,a+b=2.0 to 4.0in an amount corresponding to the expected consumption. The solution obtained is applied on the mineral building material within 3 to 30 minutes after the reactants are mixed. Suitable hydrolysis apparatus is also disclosed.

Abstract: A continuous process for the preparation of alkoxypolysiloxane in which silane or a silane mixture and a mixture of hydrogen chloride-containing alcohol and water is fed continuously into the lower region of preferably cylindrical stirred reactor, the reaction product formed together with excess hydrogen chloride-containing alcohol is drawn off continuously after residence time of 30 to 180 minutes at the upper end of the reactor and the undissolved, gaseous portion of hydrogen chloride is carried off at the head of the reactor, the temperature of the reaction mixture or the reaction product, as it flows through the reactor, being raised from a range of -17.degree. to +30.degree. C. to range of +30.degree. to +80.degree. C., the temperature gradient having to be at least 10.degree. C.