Abstract: The subject of the invention is a new thermoplastic constructional-and-insulating building material based upon fly-ashes being a waste material at combusting coal.It is composed of fly-ashes in amount of 50-80% by weight, organic porofores, for instance in form of azodicarbamide, in amount of 0.05-5% by weight, or of playing the part of porofores sawdust or wood chips having the moisture content of about 50%, in amount of 10-30% by weight, and of polypropylene in amount of 8-40% by weight.Said material shows a porous structure with sealed pores. It is featured by high mechanical strength, abrasion resistance and non-absorptivity. Thereof insulating wall and floor linings can be manufactured, as well as roofing for the agricultural and industrial building and for housing.The use of said material causes a utilization of industrial wastes lying on dumps around power plants and sawmills contributing thus to a significant reduction of pollution of the natural environment.