Structural sealant glazing (SSG) systems are a widespread adhesive bonding technology in glass facade engineering. The structural bond between the facade element and the substructure is often applied circumferentially and is commonly formed by a rubber-like two-component filled silicone elastomer. The thick, hyper-elastic bond is designed to absorb mechanical stress and strain due to wind pressure or suction, gravity, vibrations, thermal dilatation, and other loads. Compared with clamped window systems or point fixing systems, which conduct heat and cause accumulation of stresses in the glass pane, SSG-systems relief stresses and reduce heat transfer. For taking full advantage of the technology, SSG-systems therefore ideally omit retaining devices and mechanical self-weight support of the glass panes. In this case, durability of the structural bond is not only beneficial but instead necessary, as bond failure can be fatal in case of panes dropping from great heights. During its service life, the silicone bonds are exposed to climatic, chemical, and mechanical loads. At these loading conditions, the reliable performance and durability of the bonds are required for safety and for sustainability reasons. The question as to how the durability of SSG-systems can be assessed reliably is particularly relevant for approval of facade designs by building authorities. Conventional durability assessment of structural sealant joints is based on separated weathering tests and empirical fatigue testing. This dissertation deals with a newly developed test methodology for performance and durability assessment of SSG-joints at simultaneous weathering and mechanical loading. Test samples, resembling a common SSG-joint, are exposed to combined loading in a custom-designed test facility. The climatic and mechanical load functions are derived from common loading scenarios according to a worst-case approach. Two-dimensional sinusoidal load cycles subject the system specimens to tensile, compression and shear strain. Weathering comprises temperature and humidity cycles, UV-radiation, and application of water and detergent. During combined loading, the displacement and force signals are continuously measured for each system specimen. From the recorded mechanical system response, characteristic parameters like elastic moduli and dissipated energies are evaluated to assess the performance of the structural bond at varying climatic and mechanical conditions. Experimental results show a sensitivity of the system response towards ambient conditions, previous loading, and deformation amplitude peaks. The elastic moduli and dissipated energies decrease during exposure, indicating effects of dynamic stress relaxation and degradation. Hardness measurements and visual inspections of the bond regularly during exposure confirm these effects. After exposure, small-scale specimens are water jet cut from the differently exposed system specimens. Tensile and shear strengths and moduli of specimens are notably smaller after combined exposure compared with those of the non-exposed reference and weathered specimens. Along with engineering mechanical parameters, which characterise the performance and integrity of the bond, other methods reveal characteristics of the filled silicone sealant that could be affected by combined exposure. This dissertation studies how the material characteristics of two common structural sealants are affected by laboratory and field exposure. Results from TGA, FTIR-spectroscopy, DSC and SAXS/WAXS show differences between the two sealants and indicate no/minor changes in the composition and morphology of the laboratory and field exposed sealants. Mechanical characterisation methods, such as DMA, and tensile and shear testing of the structural bond, are shown to be sensitive towards the combined climatic and mechanical loadings. Mechanical characterisation methods are hence suitable for studying degradation mechanisms of structural sealants. This dissertation further discusses in which way the performance-related durability test that applies simultaneous climatic and mechanical loading can contribute to improve the reliability and performance of SSG-systems.