A process for coating microporous surfaces which have pores with a size of from 10 to 1500 nm, in which the surfaces in question are coated with at least one coating material curable thermally and with actinic radiation, after which the resulting film(s) is(are) cured thermally and with actinic radiation, wherein the coating material or at least one of the coating materials comprises (a1) at least one constituent containing (a11) on average per molecule at least two functional groups which contain at least one bond which can be activated with actinic radiation and which serves for crosslinking with actinic radiation, and, if desired, (a12) at least one isocyanate-reactive group, (a2) at least one thermally curable constituent containing at least two isocyanate-reactive groups, and (a3) at least one polyisocyanate.