What Is Structural Glazing and How Does It Compare with Captured Curtain Wall Glazing?

Structural glazing and captured curtain wall glazing can look similar from a distance, but they use different methods to secure glass to the facade frame.

The key difference is simple: a curtain wall describes the overall facade system, while structural glazing describes how the glass is attached to that system. A curtain wall can use captured glazing, structural silicone glazing, or other glazing configurations.

For architects, developers, contractors, and procurement teams, understanding this distinction helps avoid specifying the wrong system based only on appearance.

What Is Structural Glazing?

Structural glazing is a glazing method that uses structural silicone sealant to bond glass to an aluminum or other approved supporting frame. Instead of using visible exterior pressure plates and caps to mechanically retain the glass, the structural silicone becomes part of the engineered load-transfer system.

From the outside, this creates a cleaner facade because the traditional exterior aluminum pressure cap is minimized or eliminated.

For a commercial building, the visual difference is straightforward:

• Captured glazing: glass + visible aluminum cap
• Structural glazing: glass + narrow silicone joint

This is why structural glazing is often associated with flush, frameless-looking glass curtain walls.

For projects requiring a complete aluminum-and-glass envelope, PRANCE curtain wall glazing system provides examples of unitized and stick-built curtain wall configurations.

What Is an SSG Curtain Wall?

An SSG curtain wall is a curtain wall that uses structural silicone glazing. It can be built as a stick system, semi-unitized system, or unitized system.

In a unitized SSG curtain wall, the glass and frame are often assembled in the factory. This allows critical silicone joints to be applied in a controlled environment before the module is delivered to site.

PRANCE provides glass curtain wall systems in stick, unitized, and custom configurations. The appropriate glazing method should be selected according to the project’s appearance, performance, installation, and maintenance requirements.

Structural Glazing vs Captured Glazing: Main Differences 

What Is the Difference Between Butt Joint Glazing and Structural Glazing?

Butt joint glazing and structural glazing are sometimes confused because both can produce clean glass facades.They describe different things.

• Structural glazing describes how glass is attached to its supporting frame.
• Butt joint glazing describes how adjacent glass elements meet at a joint.

Therefore, a facade can potentially use structural glazing and butt joints as part of the same architectural design.

Butt glazing should also be designed around the manufacturer's glazing and sealant requirements. Guidance from the U.S. General Services Administration's Smithsonian standards treats butt glazing and structural sealant glazing as separate glazing applications.

Structural Glazing vs Captured Glazing: Thermal Performance

Structural glazing can reduce external thermal bridging because it uses less exposed exterior aluminum. W&W Glass notes that the absence of continuous exterior metal can reduce heat transfer through the facade.

However, thermal performance depends on the complete system, not the glazing method alone. Glass U-value, Low-E coating, spacer type, frame thermal break, insulation, and installation quality all affect the result.

Captured systems can also achieve strong thermal performance when they use thermal breaks and high-performance insulated glazing.

Structural Glazing vs Captured Glazing: Installation

Captured glazing is usually easier to install because the glass is mechanically clamped into the frame. Installers can see the fixing points, gaskets, and pressure plates during assembly.

Structural glazing requires stricter surface preparation, primer use where specified, silicone application, curing time, and quality control. Field-applied SSG is more sensitive to dust, moisture, temperature, and workmanship than factory-applied structural silicone.

For complex projects, the factory pre-coated glazed structural system can reduce on-site risks as the critical silicone joints have been completed before delivery. PRANCE applies this method to modular curtain walls, where the frames and glass modules are assembled with gaskets, clamps and sealants before shipment.

Structural Glazing vs Captured Glazing: Maintenance

Captured curtain wall glazing is easier to inspect because the pressure plates, caps, gaskets, and fixings are visible. Damaged gaskets or loose caps can often be identified during routine facade inspection. 

Structural glazing requires a maintenance plan focused on silicone condition. Inspect for loss of adhesion, cracking, discoloration, bubbling, or separation at the glass-to-frame joint. 

PRANCE’ s glass curtain wall maintenance and safety guide recommends routine inspection of sealants, gaskets, drainage paths, and frame connections. For SSG systems, silicone inspection should be treated as a priority because it is part of the structural load path.

Conclusion

The simplest way to remember the difference is:

Captured curtain wall glazing mechanically holds the glass. Structural glazing bonds the glass to the frame with structural silicone.

Neither approach is automatically better for every project.The right choice depends on the required facade appearance, wind and water performance, thermal requirements, building movement, construction method, maintenance strategy, and project budget.

For developers and contractors, the best specification is therefore not simply "structural glazing" or "curtain wall glazing." It should define the complete curtain wall system, glazing method, glass configuration, performance requirements, testing, and maintenance strategy.

For projects requiring customized aluminum-and-glass facade solutions, PRANCE Glass Curtain Wall Manufacturer provides additional information on unitized, stick-built, structural glazing, and point-fixed facade systems.

FAQ

1.Is structural glazing the same as a curtain wall?

No. A curtain wall is the overall non-load-bearing facade system, while structural glazing describes a method of attaching glass to the supporting frame.

2.Is SSG stronger than captured glazing?

Not automatically. Both systems require project-specific engineering for wind, water, movement, glass, framing, and connections.

3.Can structural glazing be used with a unitized curtain wall?

Yes. Structural glazing describes the glass attachment method, while unitized describes how the curtain wall panels are assembled. The two can be combined.

4.What is butt joint glazing?

Butt joint glazing refers to the way adjacent glass panels meet at a joint. It is different from structural glazing, which describes the glass-to-frame attachment method.

5.Which is easier to maintain?

Captured glazing is generally more accessible for mechanical component and glass replacement. Structural glazing requires more specialized procedures when bonded glass or structural silicone needs to be repaired.