A two-part curable foaming composition comprising: (A) A first part comprising: (i) an alkoxysilyl capped prepolymer; and (ii) a polyhydrogen siloxane; (iii) optionally a catalyst which accelerates both foaming and cross-linking through said alkoxysilyl groups; and (B) A second part comprising: (i) a nitrogen-containing compound having an active hydrogen; (ii) water; and (iii) optionally a catalyst which accelerates both foaming and cross-linking through said alkoxysilyl groups; provided that at least one of the parts contain a catalyst and wherein after mixing together the first and second parts a cured elastomeric foam is formed.