Curtain Wall Glass

What is a Curtain Wall System?

A curtain wall is a non-load-bearing outer skin attached to a building’s structural frame. Unlike traditional masonry or stud-framed walls, it hangs from the floor slab edges, spanning multiple storeys and acting as the primary barrier against wind, rain, and thermal transfer. Since the system carries no structural load, it can be fabricated primarily from lightweight aluminum framing and glass, which is what makes the sweeping glass façades of contemporary commercial architecture possible.

Non-structural does not mean simple. These systems must flex and accommodate lateral movement during seismic events and high wind loads without cracking or detaching. In British Columbia, Canada’s most seismically active province, that flexibility is a life-safety requirement. Anchorage details and fixing points must be designed and certified by a professional engineer registered in BC, which makes glass specification an integral part of the structural engineering process from day one.

Curtain Wall System Types

Curtain wall systems are categorized by how they are assembled and installed. Understanding the differences helps clarify what glass specifications are needed at each stage of your project.

Stick-Built Systems

Stick-built curtain walls are assembled piece by piece onsite. Mullions, transoms, and glass panels are shipped separately and installed sequentially by glazing contractors. This approach suits irregular building shapes and lower-rise applications where factory-assembled modules would be difficult to handle. The trade-off is time: stick-built systems require more onsite labour, and misalignment during erection can reduce the critical glass bite dimension, compromising the seal between glass and frame.

Unitized Systems

Unitized curtain walls are pre-assembled in a factory as complete units, each typically one storey tall and approximately 1.5 to 1.8 metres wide. Panels are shipped to the construction site, lifted into position, and locked together. Building in a controlled manufacturing environment delivers tighter quality control than field assembly on a busy construction site. For high-rise buildings, unitized systems are the preferred approach because the speed of installation and consistency of performance justify the upfront fabrication investment.

Semi-Unitized Systems

Semi-unitized systems offer a middle ground, with some components pre-assembled off-site and others completed during installation. This hybrid approach provides scheduling advantages on projects where certain design elements suit factory assembly while others require onsite customization.

Glass Products for Curtain Wall Applications

There is no single curtain wall glass solution. Every project demands its own set of decisions around safety, thermal performance, acoustics, and aesthetics. We manufacture a comprehensive range of glass products suited to curtain wall applications, and our team works directly with architects and contractors to identify the right specification for each project.

Insulated Glass Units (IGUs)

Insulated glass units are the workhorse of commercial curtain wall glazing. An IGU consists of two or more glass panes separated by a spacer system and hermetically sealed, with the cavity filled with argon gas to improve thermal performance. We manufacture our IGUs using a flexible spacer, which delivers superior edge seal performance and reduces thermal bridging at the perimeter of the unit, exactly where condensation risk is highest in curtain wall assemblies.

Heat Treated Glass

Tempered glass is thermally treated to achieve significantly greater strength than annealed glass of the same thickness. On breakage, it fractures into small, blunt-edged granules rather than sharp shards, which is why code requires tempered glass in curtain wall applications where human contact or public safety is a concern. We operate two convection furnaces capable of producing consistently heat-treated glass that meets or exceeds applicable standards for curtain wall façades.

Heat-strengthened glass is also available for applications where increased strength and better thermal stress resistance are needed without the full fracture characteristics of tempered glass. It is commonly specified as the inboard lite in laminated curtain wall assemblies where post-breakage retention is a priority.

Laminated Glass

Laminated glass bonds two or more panes together using a polyvinyl butyral (PVB) or SentryGlas interlayer. On breakage, the interlayer holds the fragments in place rather than allowing them to scatter. This makes laminated glass the right choice for overhead glazing, high-security applications, and any situation where post-breakage retention is a code or design requirement. The interlayer also improves acoustic performance, a meaningful benefit for curtain walls on buildings in urban environments or near transportation corridors.

Low-Emissivity (Low-E) Coatings

Low-E coatings are microscopically thin metallic oxide layers applied to glass surfaces to selectively control heat transfer. By reflecting long-wave infrared radiation, low-E glass reduces heat gain in summer and retains interior warmth in winter. For curtain wall projects in British Columbia, where compliance with ASHRAE 90.1 and the BC Energy Step Code governs envelope performance, the U-value of the glazing assembly is a non-negotiable specification parameter. Low-E coatings are one of the most effective tools for hitting those targets without sacrificing visible light transmission.

Spandrel Glass

Spandrel panels are the opaque sections of a curtain wall assembly, typically positioned at floor slab levels to conceal structural elements, mechanical systems, and fire safing insulation. We manufacture spandrel glass that deliver consistent colour and opacity across large façades. Getting that match right between spandrel and vision glass is a detail that separates a polished installation from a mediocre one, and it requires careful attention to glass selection, coating specification, and manufacturing consistency.