The invention relates to a multilayer material comprising (a) a first layer that consists of plaster or that substantially consists of plaster, and (b) at least one second layer, comprising a sandwich textile fiber material. The fibers of said material are interlinked in a mechanically stable manner, are incombustible and weather-proof and the interspaces are filled with a finely porous material. The second layer has a diffusion-equivalent air layer thickness of not more than 2.0 m and is water-impermeable at a water pressure of at least 100 mm water column. The inventive material can be used outdoors due to its properties. The invention further relates to methods for producing such a material.