A moisture-curing composition including a) at least one moisture-reactive polymer P with a proportion of 10% to 60% by weight, based on overall composition, b) at least one inorganic filler F with a proportion of at least 9% by weight, based on overall composition, c) between 3% and 25% by weight, based on overall composition, of at least one type of microscopic hollow beads H, wherein composition has density of less than 1.20 kg/l, and microscopic hollow beads H have compressive strength, measured to ASTM D3102-72, of at least 2.5 MPa, and microscopic hollow beads H have a volume-based particle size D90, measured by Coulter counter, of less than 100 μm.