An embodiment relates to a redispersible polymer powder (RDP) composition for use in the preparation of dry mortar formulations, especially of cementitious bound tile adhesives (CBTA) and adhesives for external thermal insulation composite systems (ETICS). An embodiment further relates to a dry mortar formulation comprising said RDP composition. Embodiments relate to the composition and manufacture of water-redispersible polymer powders that comprise polyurethane powders, particularly where said polyurethane powders comprise particles of ground polyurethane foam. An embodiment is further directed to a method of improving adhesion of said polyurethane powder particles to mineral components of a dry mortar formulation. Furthermore, an embodiment is directed to a method of improving impact resistance of a cured dry mortar formulation without deteriorating workability of the wet mortar or the adhesion strength of the cured dry mortar formulation.