The invention relates to fiber-containing pasty construction materials, containing a) one or more fillers, b) optionally additives, characterized in that they contain c) fibers, d) one or more polymers based on one or more ethylenically unsaturated monomers, having a glass transition temperature Tg of ≧−15° C., e) ≦5% by weight hydraulically setting binders and f) water, wherein the information in % by weight relates to the dry weight of the fiber-containing pasty construction materials. The invention also relates to a process for producing a reinforcing composition free of woven reinforcing fabrics.