The most important area of resource conservation is the extensive use of secondary products of the industry as feedstock to produce building materials. Benefits of secondary products usage are to enhance the physical and mechanical characteristics and strength characteristics of the resulting building materials. By-products of different sectors of industry, such as ash and slag waste from combined heat and power systems and glass industry cullet, which provide the industry with huge sources of cheap and prepared raw materials, are used as accessory materials. They reduce the cost of producing certain materials. Three main mixtures are addressed in the article: (1) a mixture of cement, ash and slag waste and glass cullet, (2) a mixture of clay and ash and slag waste, and (3) a mixture of clay, ash and slag waste and glass cullet. The production processes of the tested materials are described: preparation and thermal treatment of raw materials. Material properties obtained after the roasting were determined: compression capacity, absorption of water and level of firing shrinkage. Not all materials are amenable to characterization techniques used in standardized ways of testing.