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Throughout April UrbanToronto is featuring a special State of Environment editorial series to explore critical sustainability issues across our region.
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A previous edition of Explainer described how exterior sunshading devices, or brise soleils, have the ability to greatly reduce the solar heat gain of a building. When this particular architectural element is used in tandem with a double-skin facade, energy performance is optimized. Consisting of two building envelopes, an outer and inner layer, a double-skin facade creates an intermediate space that serves as a ventilating cavity, supported naturally or mechanically. The system acts as a thermal buffer that moderates occupant comfort, promoting air flow through the cavity and reducing energy consumption by providing heat in the winter and shading in the summer.
The concept of the double-skin facade was first explored and employed by Swiss-French architect Le Corbusier, who inserted heating and cooling pipes between large layers of glass, a system he called a mur neutralisant (neutralizing wall). Architects experimented with the system around the world but it never quite penetrated the industry to reach mainstream status. However, a recent drive for energy-efficient and environmentally friendly buildings has sparked a renewed interest in double-skin facades, with high-profile buildings like 30 St Mary Axe in London, the Düsseldorf City Gate (Stadttor) in Germany, and Shanghai Tower in China adopting the practice.
Compared to a conventional glazing configuration, double-skin facades generally achieve a higher insulative value, regulating the temperature and acoustic properties of a building. The solar heat gain captured within the cavity can be circulated throughout the occupied space to offset heating requirements in cooler climates, while the cavity can be vented out to reduce heat buildup in warmer climates. But the efficiency and performance of the system is highly dependent on consistent maintenance.
The former Occidental Chemical Center in Niagara Falls, New York, essentially a nine-storey glass cube, implemented the first double-skin facade in North America. An independent energy analysis predicted that the structure would use only two percent of a conventional building’s energy for winter heating and 19 percent annually for cooling. But grossly inadequate maintenance meant that the mechanized louvers would stop functioning, and air-intake grilles were covered to prevent the cavity from accumulating dirt and particulates from a nearby excavation site. The system was effectively rendered useless and now serves as a cautionary tale for owners who habitually ignore and defer building upkeep.
Critics contend that similar insulative values can be attained by using conventional high-performance, low-e windows, instead of having to sacrifice usable floor space for the cavity. The material and design costs of enacting the system can also be prohibitive; as a result, double-skin facades continue to be found almost exclusively on high-profile and big-budget projects.
Have any other construction and development terms that you would like to see featured on Explainer? Share your thoughts and questions in the comments section below.
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Do you have other planning terms that you would like to see featured on Explainer? Share your comments and questions in the comments section below!
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From 2015 to 2017, and then expanded in 2022, UrbanToronto ran an occasional series of articles under the heading Explainer. Each one took a concept from Urban Planning, Architecture, Construction, or other topics that often wind up in our publications, and presented an in depth look at it. We are again revisiting (and updating where necessary) those articles. While you may already be well versed in the terms and topics we explored, others may be new to you. We will be (re)publishing Explainer on an occasional basis. Want to read other Explainers? Click on the Explainer box at the top of the page.
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UrbanToronto’s new data research service, UrbanToronto Pro, offers comprehensive information on construction projects in the Greater Toronto Area—from proposal right through to completion stages. In addition, our subscription newsletter, New Development Insider, drops in your mailbox daily to help you track projects through the planning process.
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Thank you to the companies joining UrbanToronto to celebrate State of Environnent Month.