Understanding large glass spans: Innovation, engineering and performance in modern glazing

Natural light, panoramic outdoor views and impressive building aesthetics – large glass spans are a defining feature of contemporary architecture. Often measuring up to 15 square metres in surface area, large glass panels create uninterrupted connections between interior and exterior spaces. They deliver minimalist design with maximum visual impact, enhancing residential, commercial and public architecture.

Although oversized glass panels are increasingly popular, they still pose several challenges that must be carefully considered and planned for. Solarlux technical lead Justin Spires explains some of these difficulties and how they can be overcome with suitable planning and specification.

“Large glass spans are extremely heavy, weighing up to a ton or more, depending on the glass's size and thickness,” Justin explains. “This weight must be considered in the early planning stages of the surrounding building structure,” he adds.

“The larger a glass span is, the more wind will hit its surface at any given time. This means more potential for deflection,” Justin warns.

“At the design stage, careful orientation of the building can play a crucial role in mitigating wind loading on large spans of glass. Minimising the glazing’s exposure to prevailing winds can significantly reduce lateral pressure and deflection.

“In terms of the glass itself, thicker glass can be used to reduce deflection, while specialist treatments such as lamination, tempering and pre-stressing can strengthen the glass panel,” he says.

He also notes that the frame of the glazing system is critical for preventing deflection and supporting the glass, even in high winds. “Depending on the project requirements, larger glass spans may require wider profiles to provide adequate support. Solarlux systems can also include steel reinforcement within the vertical profiles for added strength, the steel elements are completely hidden within aluminium profiles and do affect the thermal performance of the system.” he says.

Justin explains that large glass panels are exceptionally heavy and they must be handled with extreme care. Precision is critical to prevent stress, vibration or flexing during transport and installation, which could compromise the integrity of the glass. “Each panel is meticulously prepared and transported upright to preserve dimensional integrity and surface quality. Once on site, they are moved into position using specialist equipment such as vacuum lifters, cranes and automated handling systems,” he explains.

As demand for large glazing panels has grown, manufacturers have developed advanced materials and engineering techniques to deliver exceptional performance and precision.

While advances in glass manufacturing have provided the strength needed for larger spans, the framing systems that support them have also progressed.

Solarlux’s precision-engineered aluminium frame systems can be reinforced with steel inserts to provide strength and rigidity. This allows large glass spans to be supported while maintaining a slim, minimalist aesthetic.

Our glazing systems are tailored to each project’s specific requirements. This allows architects to specify very large glass spans, while ensuring that performance criteria – including structural integrity, wind resistance and thermal efficiency – are fully met.

• Thermal performance – Approved Document L (England) sets maximum U-values for building elements, including walls, windows and doors. While large glass spans increase the potential for heat loss compared with walls, features such as low-E coatings and double- or triple-glazing ensure the glass itself remains thermally efficient. Instead, the frame is usually the primary source of heat loss in these systems. To optimise energy performance, structural glazing frames should be thermally broken and designed to avoid thermal bridging.
• Air and water tightness – Large glass spans should be suitably sealed against air and water infiltration. Solarlux systems have integrated drainage to direct excess water away.
• Acoustic insulation – Laminated glass can include interlayers that reduce external noise, while double- and triple-glazing also provides sound damping.
• Solar gain and shading – Large spans of glass increase the potential for summer solar heat gain, raising the risk of overheating. Approved Document O (England) requires that unwanted solar gains be limited. The right method will depend on the project, its location and design, but options include building orientation, shading systems and solar-control coatings on the glass.

Ensuring that large-format glazing performs safely and reliably requires rigorous testing.

Testing verifies structural integrity, wind and weather resistance, impact performance and long-term durability. It provides confidence that the glass will meet both regulatory and project-specific requirements. It can also support building or manufacturer warranties by demonstrating compliance with industry standards.

Several industry standards apply to large spans of glazing, describing expected performance characteristics, providing classification systems or describing testing procedures. For example:

• BS EN 12150-1:2015 is the standard for thermally toughened soda lime silicate safety glass used in buildings. It sets requirements for strength, safety and how the glass breaks, ensuring it shatters into small, relatively harmless pieces rather than large shards.
• BS EN 12207:2016 and BS EN 12208:2000 are European standards that provide classification systems for the air permeability and watertightness of windows and doors, respectively.
• BS EN 12600 is a European standard for classifying the impact resistance of safety glass. Testing is carried out by dropping a weight from different heights.

The Centre for Window and Cladding Technology (CWCT) has also set standard test methods for building envelopes. The test results describe how well a glazing system performs under severe weather conditions and impact.

Solarlux glazing systems are independently tested to applicable BS EN standards, giving specifiers confidence in the product’s safety, performance and longevity.

The performance of large glass spans has come a long way, enabling the design, specification and installation of monolithic glazing structures that would once have been considered impractical or impossible. At Solarlux, we continue to develop innovative products and methods that push the boundaries of modern glazing technology and define the next generation of glass systems.

To learn more about Solarlux glazing solutions, browse our product pages or contact our team for expert technical advice and specification support.