A particulate wetting and hydrophobing additive comprising components a) and b), where: component a) is a disiloxane having structure (I) Where R2 is selected from a branched or linear hydrocarbon group of 2 to 10 carbons, a substituted branched or substituted linear hydrocarbon group of 2 to 10 carbons, an aryl group, a substituted aryl group and an optionally substituted alkyl hydrocarbon group of 4 to 9 carbons containing aryl substituents of 6 to 20 carbons; R1, R3, R4 and R5 are each independently selected from the monovalent hydrocarbon groups of 1 to 4 carbons, substituted monovalent hydrocarbon groups of 1 to 4 carbon atoms, aryl, and a hydrocarbon group of 6 to 20 carbons containing an aryl group; Z is a linear or branched divalent hydrocarbon radical of 1 to 10 carbon atoms and R8 is selected from OH, H, monovalent hydrocarbon groups of 1 to 6 carbons and acetyl, each of the subscripts a, b and c are zero or positive provided that a+b+c≧1; and component b) is a carrier.