Abstract
Membrane materials used for roof structures of buildings have a relatively low thermal insulation capacity compared to the classic building materials. Phase Change Materials are applied to improve the insulation effect of the membrane materials. Phase Change Materials absorb energy during a heating process if the Phase Change takes place. Otherwise this energy can be transferred to the environ ment in the phase change range during a reverse cooling process. The insulation ef fect reached by the Phase Change Material is dependent on temperature and time, and presents in this way a new kind of insulation very different from the insulation properties of any other material. The development of new testing methods was nec essary to determine the insulation effect of materials which incorporated Phase Change Materials.