Architects and LEED professionals understand the numerous benefits of building with wood, including potentially better performance than concrete and steel and significantly lower emissions.

But many are unaware of how wood can be used in a timber curtain wall (TCW). Today’s TCW technology provides opportunities to incorporate wood’s beauty and energy efficiency into glazed facades that not only bring the outdoors into the interior, but also serve as the building’s heavy lifter.

Unicel Architectural’s Luc Paquet presented at this year’s Top Glass conference in Mississauga on the promise of wood-glazed facades for tomorrow’s energy-efficient buildings. He also explored new ways of using wood to reduce the carbon footprint of a building using new technologies.

Here’s a rundown of his presentation.

What is a Timber Curtain Wall?

TCWs are a more aesthetically pleasing alternative to standard aluminum curtain walls and combine the benefits of biophilic design with glazed facades. They can support large glass assemblies with narrow mullions, allowing for dazzling exterior views, large amounts of natural light, and the warmth of interior timber.

The flexibility of these systems allows them to support glass weights of up to 600 kg per unit and sloped glass roofs with inclinations as low as two degrees.

Because TCWs are fully customizable and easily installed on steel, concrete, or timber structures, they offer design versatility that supports clean sightlines and the extension of the interior space into the exterior.

TCWs aren’t just a rich design feature, though. TCWs can also include load-bearing capabilities and support net-zero and passive building criteria.

Indeed, the use of wood has significant environmental benefits: Because wood products are approximately 50 percent carbon by dry weight, wood – unlike aluminum or steel – acts as a carbon sink able to store large amounts of carbon for a long time when used as a building material. Wood also provides natural insulation and helps improve interior comfort and temperature control.

A recent paper by researchers at the Potsdam Institute for Climate Impact Research showed that if 10 percent of new buildings were made of timber, it could result in 10 million tons of additional carbon storage. The same paper indicated that 90 percent new wood builds could result in 700 million tons of carbon storage.

What Components Are Part of a Timber Curtain Wall?

A typical TCW system includes the following components:

1. Wood mullion: Can be made from various wood species such as Douglas fir, pine, mahogany, sapele, red cedar, white oak, and maple. Mullions are typically either laminated or glulam. Manufacturers offer engineered lumber in various types and finishes based on design, engineering parameters, and cost.

2. Base aluminum profile: Attached to the wood mullion with screws.

3. Mullion gasket: Sits above the base to provide an elastic seal between the wood and glazing systems.

4. Triple-glazed, insulated units: The actual glazing sits on either side of the optional insulating block (see (6)).

5. Pressure plate and gasket: Hold the insulated units in place, along with screws through the base aluminum profile.

6. Insulating block: An optional feature, the insulating block can help mitigate extreme temperatures.

7. Aluminum or wood beauty cap (exterior): Snaps into place for a finished, clean exterior look.

All these components can be assembled modularly (instead of stick-built), which typically results in considerable time and cost savings. TCW modules are prefabricated at the manufacturing center, with anchors and membranes already installed on the modules and all finishes applied at the factory in ideal conditions. The glazing is then installed at the job site.

Modular construction projects are generally regarded as having a much lower cost per square foot.

Timber Curtain Wall: The Advantages

Along with their aesthetic appeal TCW features several environmental, structural, and health benefits. Structurally, TCW can support all the loads of the actual curtain wall along with the weight of the roof and that of the upper floors (if necessary), allowing for truly innovative design flare.

TCW are also capable of being up to 72 percent more energy efficient than a standard curtain wall.

That’s because TCW helps manage:

• Thermal conduction (the progressive diffusion of the thermal agitation through physical contact) through high-quality weatherproof gaskets and isolation foam
• Thermal convection (the thermal transfer that accompanies the macroscopic displacements driven by buoyant forces, such as heat rising) through isolation foam
• Thermal radiation (the propagation or radiating of photons through space carrying radiant energy) through insulating glass units (IGUs) with a warm edge spacer, argon gas between panes, and Low-E glass windows that reflect heat

These and other benefits help TCW qualify as certified Passive House components, thanks to thermal simulation testing resulting in very low thermal transmittance. TCW features lower energy loss and the ability to maintain room temperatures without as much heating or cooling as typical curtain wall or window systems.

Passive House is a building standard aimed at reducing a building’s ecological footprint and creating ultra-low energy consuming buildings. It’s a vital tool in the fight for sustainability, considering that buildings are responsible for 40 percent of global energy consumption.

The rich wood interiors provided by a TCW can additionally provide health and wellness benefits thanks to the science of biophilic design. Biophilic design involves adding natural elements (such as wood, stone, and plants) within a building’s interior, which can lead to improved productivity, motivation, and well-being.

Unicel Architectural’s Timber Curtain Wall in Action

Unicel Architectural’s custom timber curtain wall has German technology at their core, providing architectural design freedom with versatile technology that can be installed in nearly any building.

Recent Unicel Architectural timber curtain wall projects include:

• Princeton University Residential Colleges
• Wellesley College Science Complex
• Quinnipiac University’s Recreation and Wellness Center
• Wuehrer House (East Hampton, NY)
• Chibougamau-Chapais Airport Terminal Building
• Osler Bluff Ski Club
• Pavillon d’accueil du Parcours Gouin

Contact us today to learn more about what Unicel Architectural’s timber curtain walls can do for your next project.