What Is Structural Silicone Glazing (SSG)?

Structural Silicone Glazing, or SSG, is a façade solution in which certain loads on the glass are transferred to the supporting frame through structural silicone joints. Wind effects that are transferred through pressure plates or mechanical retainers in conventional systems are carried into the frame through designed bonding surfaces instead. This reduces the mechanical retainers visible from outside and allows a more continuous glass surface. The role of structural silicone differs from that of a weatherseal providing air and water tightness; the suitability of the product used for load transfer must be verified for this application. Where insulating glass is used, the role of the edge seal between the panes in transferring load is also examined.

In SSG design, the bite width and silicone thickness are determined from the glass dimensions, design loads, expected movements and the permissible design stresses of the product. The self-weight of the glass is carried by mechanical supports in most solutions. If that weight is to be transferred through the silicone instead, the behaviour of the product under sustained load and its suitability for that use must be verified separately. Design stresses permitted for sustained loads can be markedly lower than the values given for short-term loads. Surface preparation, adhesion and compatibility testing, curing conditions and application quality control matter as much as the calculation. Joint details should be finalised together with the project assessment of the selected silicone manufacturer.