A water curable composition comprising:(a) at least one polymer selected from the group consisting of silane grafted homopolymers of ethylene, propylene, or 1-butene; silane grafted copolymers wherein a major proportion thereof is attributed to an ethylene, propylene, or 1-butene monomer; and a copolymer wherein a major proportion thereof is attributed to an ethylene, propylene, or 1-butene monomer and a minor proportion thereof is attributed to silane, each polymer having at least one silane moiety containing at least one hydrolyzable group; and(b) at least one polysiloxane having the following formula: ##STR1## wherein R=C.sub.3 H.sub.6 (OC.sub.3 H.sub.6).sub.y (OC.sub.2 H.sub.4).sub.2 OR'R'=a radical selected from the group consisting of hydrogen, an alkyl radical having 1 to 4 carbon atoms, an alkyl acetate ester radical wherein the alkyl group has 1 to 4 carbon atoms, and a trimethyl silyl radical, and each R' is alike or differentw=about 20 to 120x=1 to about 24y=0 to about 10z=about 4 to 25y+z=about 5 to 30.