Curtain Wall
CSI Division 08, Openings
A non-structural exterior wall system, typically a grid of aluminum framing infilled with glass, metal panels, or stone, that hangs off a building's structural frame rather than supporting any of the building's structural load itself, common on mid-rise and high-rise commercial buildings.
Why it matters
Because a curtain wall spans multiple floors and has to accommodate the building's structural movement, wind sway, seismic movement, thermal expansion, without cracking or leaking, its connections back to the structural frame are engineered specifically to allow that movement, and a curtain wall installed as if it were rigidly fixed can crack or fail as the building moves normally around it.
On a real project
A 20-story office tower's curtain wall is engineered with connections back to the structural frame that allow for the building's expected wind sway and thermal movement, so the glass and framing don't crack as the structure flexes under normal conditions.
Who this matters most to
A Project Engineer coordinates curtain wall shop drawings and mockup approval well in advance of installation, since a curtain wall system is highly engineered and manufactured to order. A Quality Control Manager often requires a full-scale mockup panel tested for water and air infiltration before the full curtain wall order is released for fabrication.
Where this goes wrong
A curtain wall subcontractor's shop drawings show a connection detail that doesn't actually accommodate the building's calculated movement, and the discrepancy isn't caught before fabrication. After installation, thermal cycling over the following seasons cracks sealant joints that a properly detailed connection would have tolerated, requiring an expensive re-seal of large sections of the building's exterior.