The object of the invention is a method for the production of foams on silicon basis from polymer mixtures (A) containing silicon, wherein at least one compound (V) is used that contributes to the formation of the polymer network, and which carries at least one alkoxy silyl group of the general formula [1a], [1b], or [1c] ≡Si—O—(R1)(R2)(R3) [1a], ═Si(R5)—O—C(R1)(R2)(R3) [1b], ≡Si—O—C(O)—U [1c], from which upon curing of the polymer mixtures (A) at least one molecule (XY) is split which is gaseous during processing and causes the formation of foam in the polymer mixture (A), and a catalyst (K) selected from a Brönstedt acid, Brönstedt base, Lewis acid, and Lewis base, where R1, R2, R3, R5, and U have the meanings as stated in claim 1, and where polymer mixtures (A) which form SiO2 during the cross-linking process are excluded. The invention further relates to a method, wherein the foam layers, foamed molded bodies, adhesive or sealing masses are produced, and foams on a silicon basis, which can be obtained from the polymer mixtures (A) according to the previous mentioned method.