Choosing between SSG curtain walling and capped curtain walling is dependent on a wide variety of design and practical factors, which we’ll explore in this overview.
Let’s firstly define each curtain wall type:
SSG means a structurally silicone glazed curtain wall system, which uses a structural silicone sealant containing an integrated profile around the perimeter of the glazing cavity.
Toggles placed in the channel profile of mullions and transoms afford a mechanical attachment, securing the pane to the curtain wall. A weather sealant finish provides a flush and seamless external appearance to the SSG curtain wall detail.
Kawneer offers two dedicated SSG curtain wall systems – AA®100 Structurally Silicone Glazed (SSG) and AA®110 Structurally Silicone Glazed (SSG).
Available in a wide range of colours and finishes, a capped system features an attractive cover cap fixed vertically and/or horizontally to an external curtain wall pressure plate, with exposed and visible mullions, holding glass panels in place and providing a weathertight seal.
Typical Kawneer capped curtain wall systems include the AA®100 50mm Curtain Wall System and the AA®110 65mm Curtain Wall System.
The sleek aesthetics of a structurally silicone glazed curtain wall system has led to the widespread appeal of this type of curtain walling.
Aesthetic advantages:
• Creates a seamless external appearance to the curtain wall.
• No exterior framing.
• A clean, contemporary look.
• Affords a very popular minimalist aesthetic.
• A smooth, uninterrupted glazing surface.
• Eminently suitable for high-tech/high-rise and curved building designs.
Practical advantages:
• Highly effective weather sealing.
• Superior thermal performance.
• Optimal airtightness.
• Suites with high-performance glazing.
• Flexible accommodation of thermal expansion/contraction/building movement.
• Lowers stress on glazing and other curtain wall components.
• UV, weathering, aging resistance.
• Can help reduced noise transmission.
Disadvantages:
• Reduced design flexibility compared with a capped curtain wall.
• Reliance on silicone bonding limits suitability with some types of glass.
• Quality control is critical – mistakes can compromise the entire SSG curtain wall system.
• Regular inspection and maintenance of the system are critical to prevent future issues, e.g. sealant degradation.
• SSG curtain wall installation time must include curing time of the silicone bond.
• Panel replacement can be complex.
• Not suitable for all building types/designs.
• No mechanical fastening as a back up to silicone failure.
• Requires skilled labour and precise installation techniques.
• Limited building movement tolerances +/- 2.5mm in most cases.
Capped curtain walling is immensely popular with designers all over the world, due to a range of key benefits, including ease of installation and maintenance, plus cost-efficiency.
Aesthetic advantages:
• A curtain wall cap is the perfect solution for buildings that can benefit from a framed appearance.
• Accommodation of an extremely wide range of glass types/thicknesses.
• Suitability for the widest range of applications.
• Exterior curtain wall cap profiles are available in a vast range of custom colours and finishes to complement the structure’s overall design aesthetic. The visible caps provide a distinctive, structural look that can enhance the architectural design of a building.
• Simplified panel replacement compared with an SSG solution.
• Concealed zone (multiple sections) or mullion (every transom) drainage options. SSG is mullion-drained only.
• These systems can allow for larger glass panels, maximising the natural light into the building.
Practical advantages:
• Long track record of proven reliability.
• Wide installation expertise.
• Speed of installation.
• Excellent weather sealing when using correct installation techniques.
• Pressure plates provide mechanical fastening back up.
• Easy visual inspection, compared with SSG curtain walls.
• Relatively low cost.
• Less critical alignment/tolerances.
Disadvantages:
• The “grid” appearance of curtain wall capping, when repeated over a large surface, provides less sleek lines than an SSG solution.
• The curtain wall cover cap is less suited to a minimalist, high-tech appearance.
• Thermal performance is highly dependent on installation integrity and the overall curtain wall system design.
• Frequent cleaning maintenance is required to avoid dirt, dust and water streaking.
• Reduced suitability for curved curtain walling configurations.
• Arguably less creative freedom due to framed curtain wall capping appearance.
• Not always ideal for high-rise buildings, due to multi-stage installation processes, versus an off-site assembled, modular unitised curtain wall system.
A Comparison of Kawneer SSG/Capped Solutions
The following table provides a comparison of key properties of the following Kawneer curtain wall systems:
AA®100 50mm Curtain Wall System
AA®100 Structurally Silicone Glazed (SSG)
AA®110 65mm Curtain Wall System
AA®110 Structurally Silicone Glazed (SSG)
So which system is right for you?
Choosing between SSG curtain walling and capped curtain walling depends on your specific design and practical needs.
SSG curtain walling offers a sleek, seamless appearance with superior weather sealing and thermal performance, making it ideal for high-tech, high-rise and curved building designs. However, it comes with higher installation costs, great reliance on silicone bonding and limited design flexibility.
Capped curtain walling provides a framed aesthetic, suitable for a wide range of glass types and finishes, easier panel replacement and lower costs. It is suitable for a broader range of applications and accommodates increased building movement tolerances. It may, however, require more ongoing maintenance and will struggle to achieve the minimalist look of SSG systems.
Ultimately, the choice between these systems should be guided by your project’s aesthetic goals, budget constraints, and practical requirements.
Kawneer’s Architectural Advisor Team is always on hand to help you choose the most optimal solution.