A Glass Fiber Reinforced Polymer (GFRP) retrofitting system for masonry using a polyurethane dispersion for both as matrix and for application is presented (the GFRP system is later on referred as "seismis wallpaper"). A large laboratory test campaign mainly consisting of single shear tests has demonstrated a very soft and at higher loads highly inelastic material behavior. This behavior and the failure modes being observed cannot be quantified using already existing guidelines or avaible research data, as this data is based on FRP-systems using epoxy matrices. As the system has already proven its reinforcing effect for earthquake loaded walls , further standardization activities have been carried out. A standardization approach basing on the bond-slip model is presented. Numeric simulations which are in good agreement with the laboratory test data underpin the chosen approach.