More stringent building physics requirements on the outer shell of buildings increasingly require a multi-layer wall structure. Precast concrete elements that meet these requirements include sandwich walls and core-insulated element walls. The prefabricated reinforced concrete wall elements have a three-layer wall structure consisting of an facing layer, a thermal insulation layer and a load bearing layer. The concrete surface layers are increasingly coupled using connectors made of glass fibre reinforced polymer. The rod-shaped connectors are usually subjected to tensile forces. The decisive factor for the load-bearing capacity of the connectors during construction is their anchoring in the normal concrete of the facing layer. Temperature induced constraint can lead to crack formation in the anchoring base of the connectors and influence the pull-out loadbearing capacity of the GRP sandwich connectors. In the context of this contribution, experimental investigations on the pull-out behaviour of GRP connectors in the concrete of the facing shell under varying crack width are presented and evaluated.