Membrane materials for fabric structures consisting of a woven fabric which is coated on one or both sides with an elastomeric compound comprising finely divided phase change materials such as crystalline alkyl hydrocarbons or salt hydrates. The membrane materials facilitate thermo-regulation due to latent heat absorption and latent heat release in the phase transition range of the phase change material, which enhances the thermal comfort of the enclosed structure, they are applied to and leads to energy savings.