The present disclosure relates to a method for producing rigid polyurethane foam composite elements, including at least one outer layer and a rigid polyurethane foam layer, by mixing (a) polyisocyanates with (b) compounds having at least two hydrogen atoms reactive with isocyanate groups, (c) optionally flame retardant(s), (d) blowing agent, (e) catalyst, and (f) optionally auxiliaries and adjuvants to form a reaction mixture, applying the reaction mixture to the outer layer, and curing it to form the rigid polyurethane foam. The present disclosure further relates to a rigid polyurethane foam composite element obtainable by such a method.