If you are planning a curtain wall, the first decision is the system type. We compare the look, performance and cost of structural silicone, capped and semi-capped curtain walls.
A curtain wall is an outer skin hung from the building structure that carries no load other than its own weight. The first decision on any curtain wall project is the system type: structural silicone, capped or semi-capped. The three differ in appearance, performance and cost.
Structural silicone glazing
In a structural system, the glass is bonded to the aluminium frame with structural silicone. No profiles are visible from outside; the building reads as a single glass volume.
- Pros: seamless, prestigious appearance; flat surface that is easy to clean.
- Watch-outs: structural bonding must be done in a controlled workshop with full curing times. Structural calculation and silicone bite sizing are critical.
Capped curtain wall
In a capped system, glass is mechanically fixed from outside with aluminium pressure plates and decorative caps. Vertical and horizontal lines are clearly visible.
- Pros: high safety thanks to mechanical fixing; reliable in high-wind areas and on tall buildings; easy glass replacement.
- Watch-outs: cap lines must be considered part of the facade design.
Semi-capped curtain wall
In a semi-capped system, caps are used only on the vertical or only on the horizontal lines; glass is silicone-jointed in the other direction. The result is a rhythmic, balanced facade. Vertical caps make a building look taller and slimmer; horizontal caps make it look wider and more grounded.
Comparison table
| Criterion | Structural | Semi-capped | Capped |
|---|---|---|---|
| Appearance | Seamless glass | Lines in one direction | Pronounced grid |
| Mechanical safety | Silicone + safety clips | High | Very high |
| Glass replacement | Difficult | Moderate | Easy |
| Cost | High | Medium | Medium |
Which system suits your building?
The choice is not purely aesthetic. Building height, local wind load, glass sizes, maintenance plan and budget must be assessed together. At Mercan we calculate wind loads on every project, matching the architectural intent with a safe system concept.
For more on curtain walls, visit our Curtain Wall Systems page.
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