The washed-out concrete facades of an education center in EVERSTEN should be energy-efficiently refurbished by an additional thermal insulation and fiber-cement boards. The function and the load carrying safety of its joints showed partially defects, so that the load transfer of both vertical and horizontal wind loads could not be shown satisfactorily. We developed an experimental set-up to test the effects of horizontal and vertical loads separately and combined. It was designed to apply loads, specified by the European Code DIN-EN-1991-1-4. We could prove sufficient load carrying safety for all load cases without causing any critical reaction in the structure.