Abstract: The invention relates to a foam material sealing strip (1) for sealing a window frame with reference to an opening side wall. It is proposed that different foam material strips (5, 6) are impregnated for delayed recovery, in each instance, that the foam material strips (5, 6) extend over the entire thickness (d) of the foam material sealing strip (1), in each instance, and extend next to one another, at their facing longitudinal sides (7, 8), without being glued together, at least in part, in such a manner that the foam material sealing strip (1) is air-permeable in the crosswise direction, whereby the air permeability of the foam material sealing strip (1) is determined solely by the combination of the air permeability values of the impregnated foam material strips (5, 6), in each instance, and that the different vapor braking effect is achieved by means of a different initial density and/or a different impregnation of the foam material strips.