Curtain Wall vs. Window Wall: What’s the Difference?

Curtain Wall vs. Window Wall: What’s the Difference?

With the allure of urban life only growing, designers and developers must find a way to accommodate an increasing population within the limits of existing cities. Space restrictions mean building up, not out, while still providing inviting and well-built condos, offices and commercial spaces.

Curtain and window wall systems are a popular choice as they add design interest to architecture, as well as allow for maximum light within a building’s space. Here’s a breakdown of the difference between the two wall systems, plus the positives and drawbacks of both.

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What is a Curtain Wall?

A curtain wall is a glazed wall system hung off a concrete slab using anchors. Curtain walls are self-supporting and give a building’s exterior the look of top to bottom glass. Most often used on commercial buildings, curtain walls are typically installed from the outside of a building using cranes or rigs. Curtain wall installation is a complex process and can be more expensive than other systems.

What is a Window Wall?

A window wall is achieved by placing glazing between a building’s concrete slabs, using the slabs as structural support. Window walls have a break between the glass, with slab covers used to conceal the concrete. Window walls are often used in residential applications as they allow for more customizable sections such as windows and balcony doors. They are most commonly installed from the inside of a building, which is a safer, more efficient and more cost effective.

Curtain Wall Advantages

If installed correctly, curtain wall systems provide excellent structural integrity , as there are fewer mullions and joints required when compared to most window wall systems. Acting as a single unit, curtain walls are highly resistant to moisture, wind, heat and earthquakes. They require little maintenance.

Window Wall Advantages

Aside from advantages such as customizability, ease of installation and cost savings, window walls also require less engineering and safety considerations as the exterior wall is broken up by each floors’ concrete slab, providing built-in fire stopping. Also, because the separation of each window wall unit creates a sealed space there is less noise transfer and energy loss. Further, if a unit becomes damaged and needs repair that specific unit can be removed and replaced without affecting the adjoining units.

Backpans and Window Walls

When used in conjunction with curtain wall systems, insulated back pans are placed behind sections of the wall that do not require vision glass. In a curtain wall, the variances and design choices of the full assembly affect the backpan sections just as they will the glazing and other components. Because the backpans sit outside the floors, there is often variation in required height, leading to a more costly and variable manufacturing and installation process. However, in a window wall application this variation is eliminated. Pre-manufactured backpans rest between a building’s floors and are simply shimmed during installation to address any irregularities. Since most buildings are similar floor to floor, part repeatability is improved.

A Cost Comparison

For the comparable amount of glazing, window walls can be installed for half the cost – or even less – of curtain walls. Window walls are easier to install, which reduces the need for extra equipment, lifts, and handling time. Because the installation process is safer, fewer special precautions need to be taken, which further reduces cost as well as shortens the timeline of a project. Window walls also involve more repeatable components, improving efficiency during the manufacturing process. Further, a more rigid scope means most components can be assembled in shop rather than on site, resulting in fewer errors, less site disruptions and a higher quality product.

Taking Architecture to a New Level

Lenmak is proud to count EnvaTherm ® and SpandrelTherm™ as part of our product lineup. Our EnvaTherm® insulated backpans can be used in window wall systems in conjunction with opaque glass panels or architectural panels when transparent glazing isn’t required. SpandrelTherm™, our foam-insulated metal spandrel panels, offer prefinished aluminium in a wide variety of standard and metallic colours. With our innovative automated manufacturing process and highly sustainable materials and methods, Lenmak products are as sensible as they are beautiful.