Curtain Wall vs. Structural Glazing: Key Differences & Comparison
A detailed comparative analysis between conventional pressure-capped curtain walling and structural silicone glazing (SSG), examining aesthetics, engineering, and maintenance.
Key Engineering Takeaways
- Conventional curtain walls feature external aluminium pressure caps; structural glazing creates a seamless flush glass skin.
- Structural glazing relies on factory-applied structural silicone sealant meeting ASTM C1401 standards.
- 2-sided structural glazing combines linear aluminium feature bands with flush vertical joints.
Visual Aesthetics: Framing Grid vs. Flush Glass
The most noticeable difference lies in exterior visual appearance. Conventional curtain walls utilize external aluminium pressure plates and decorative snap-on caps (typically 50mm–60mm wide) that create a distinct rectangular grid across the building face. In contrast, Structural Glazing (SSG) bonds the glass panes directly to internal aluminium subframes using high-strength structural silicone sealant, leaving only a slim, flush weatherseal joint between glass panels for a monolithic all-glass appearance.
Engineering & Mechanical Fastening
In conventional capped curtain walls, glass is clamped mechanically between the aluminium mullion and exterior pressure plate using continuous EPDM compression gaskets. In structural glazing, the exterior silicone bead must support positive and negative wind pressures. For safety, 4-sided structural glazing systems also incorporate concealed mechanical dead-load supports and toggle retention clips to prevent pane loss in extreme conditions.
2-Sided vs. 4-Sided Structural Glazing
Many contemporary architects specify 2-sided structural glazing, which combines flush vertical silicone joints with bold horizontal aluminium accent caps (or vice versa). This approach creates strong linear ribbon lines while maintaining the sleek look of structural glazing.
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