Abstract: The method of production of chemically set compositions which show no shrinkage or which increase their volume during setting finding their application in building engineering, electrotechnical engineering and other fields of technology, consists in adding a special expanding system to a composition comprising synthetic resins or elastomers. Said system consists of an expanding agent, an expansion promoter, and if need be an expansion moderator, and sodium and/or potassium and/or magnesium fluosilicate. As the expanding agent substances are used having a porous structure and sorption properties, as for instance aluminosilicates, and as the expansion promoter substances are used having a polar structure and a critical diameter of the molecule smaller than that of the pores of the expanding agent, as for instance alcohols.