The invention concerns a coating composition capable of being cold vulcanised (EVF), characterised in that it comprises, in a mixture: (1) at least one polyorganosiloxane having, per molecule, at least two C.sub.2 -C.sub.6 alkenyl groups bound to silicon; (2) at least one polyorganosiloxane having, per molecule, at least two hydrogen atoms bound to silicon; (3) a catalytically effective amount of at least one catalyst, consisting of at least one metal belonging to the platinum group; (4) an adherence promoter; (5) optionally a reinforcing system which can be at least a polyorganosiloxane resin and/or a reinforcing filler; (6) optionally at least one cross-linkage inhibitor; (7) and mineral or organic hollow microspheres.