Curtain Wall vs Cladding: What's the Difference?
The terms "curtain wall" and "cladding" get used interchangeably on construction sites — but they're not the same thing. The difference matters for cost, structural requirements and approvals. Here's the simple version.
Curtain wall
A curtain wall is a complete non-structural exterior building envelope made of aluminium mullions and transoms holding glass, metal panels or stone. It hangs off the building's structural frame, carries no floor or roof load, but does carry its own weight and resist wind. It includes the weatherline — keeping rain, dust and air out.
Cladding
"Cladding" is a broader term for any non-structural surface attached to the outside of a building. ACP (aluminium composite panel) cladding, stone cladding, GFRC, terracotta cladding — all sit on top of an existing wall (block, concrete or sheathing) and are mostly aesthetic. The wall behind the cladding is what keeps weather out.
The simple test
Ask: "If I removed this surface, would the building be open to the weather?"
- If yes → it's a curtain wall (the system is the weatherline)
- If no → it's cladding (the wall behind is the weatherline)
What this means in practice
- Curtain walls need to be water-tight, air-tight, structurally engineered and tested. More expensive, more design effort, more approvals.
- Cladding is more forgiving — small gaps don't matter because the wall behind handles weather. Costs less, simpler approvals.
Common combinations
Most commercial buildings combine both. A typical UAE office tower has:
- Glass curtain wall on view-facing elevations
- ACP cladding on side/rear elevations to save cost
- Sometimes both integrated into a single visual rhythm
UAE-specific considerations
- Wind loads on tall buildings are significant — curtain wall calcs matter
- Civil defence has tightened ACP fire requirements after past incidents — only PE-FR (fire-rated) core is acceptable
- Sandstorm sealing is critical — curtain wall gaskets need annual checks
FAQ
Is a glass facade always a curtain wall?
If it's the building's primary outer envelope and contains the weatherline, yes. If it's hanging in front of an existing wall, it's cladding.
Which is cheaper?
Cladding, generally — sometimes 30–50% less per m² than curtain wall, because curtain walls require structural engineering and testing.
Can I retrofit cladding onto an existing building?
Yes — ACP and stone cladding are commonly retrofitted to upgrade older facades. Curtain wall replacement is a much larger undertaking.