Curtain Walling.
A non-loadbearing facade system that hangs off the primary structure to enclose a building.
Curtain walling is a non-loadbearing external facade system fixed back to the primary structure (usually at every floor slab) using engineered brackets. It carries no vertical load from the building above — only its own self-weight plus the wind, thermal, impact and seismic loads acting on the facade itself.
A curtain wall is built from aluminium mullions (vertical) and transoms (horizontal) forming a grid, with infill panels of insulated glass units, spandrels or metal cassettes. It is the dominant facade type on modern UK commercial, residential and mixed-use buildings because it allows lighter primary structure and large areas of glazing.
Curtain wall systems are delivered in three primary configurations: stick (assembled on site), unitised (factory-assembled storey-height panels craned into place) and structural silicone glazing (SSG, where IGUs are bonded to a carrier frame for a frameless external read).
- Stick Curtain Walling— Curtain walling assembled component-by-component on site rather than in factory.
- Unitised Curtain Walling— Curtain walling delivered as factory-assembled, pre-glazed storey-height panels.
- Mullion— The vertical structural member in a curtain wall grid that spans between floors.
- Transom— The horizontal structural member in a curtain wall grid, spanning between mullions.
- Spandrel Panel— The opaque infill panel in a curtain wall that conceals the floor slab and edge zone.