The invention relates to a method for producing a water-blown polyurethane/polyisocyanurate rigid foam material that can be sprayed, by reacting a mixture comprising an aromatic polyester polyol, a first, comparatively short-chain aliphatic polyether polyol, a second, comparatively long-chain aliphatic polyether polyol, an isocyanate component, a blowing agent having water at least as a main component, and a catalyst component. The invention further relates to a rigid foam produced according to the method according to the invention, a composite material composed of said rigid foam and a pipe, and to the use of such a composite material for transporting liquid or gaseous media.