Durable buildings, durable cities
Exploring the building envelopes of the future
From the primitive hut onwards, buildings have sheltered humans from the whims of nature. In a post-climate change world, demands on the durability of building envelopes are escalating, with ever more focus on strategies to protect occupants from extreme weather while making cities liveable.
It was in the mid-15th century that humanist polymath Leon Battista Alberti observed in On The Art of Building: “The city is like a great house, and the house in its turn a small city” – words that ring truer than ever today.
There’s no doubt that buildings, and cities, are facing unprecedented climate challenges. With variables of temperature, precipitation, humidity, solar radiation and wind speed escalating conditions such as the urban heat island effect, inevitably the performance of building envelopes is under a new level of scrutiny. But there’s also a shift taking place, with designers and engineers looking beyond the level of individual buildings to create intelligent and durable interfaces with our environments that work collectively to contribute to city resilience.
Key attributes of these new generation, civic-minded and durable buildings are summarised in Arup’s recent Cities Alive report, which focuses on arid city environments. They include strategic design that helps to cool city streets by reconfiguring air-handling systems to expel spent but still cool air at ground rather than rooftop level. Combined with new approaches to vertical xeriscape landscapes and green and blue roofs, the idea is that building envelopes acting in unison can actively improve quality of life in our cities.
A glimpse of how building envelopes of the future could perform in arid environments is offered by Grimshaw’s part-subterranean Terra Pavilion, currently on show at Dubai Expo. The architects’ vision for a net zero energy and water building combines the building envelope in one great swooping vortex. The result is a harmoniously folded surface that generates its own energy from sunlight while harvesting water from humid air. Taking cues from nature, the pavilion is surrounded by a forest of shade-giving Energy Trees – structures that track the sun like a sunflower, rotating 180 degrees over the course of the day to maximise their energy yield.
A crucial aspect of sustainable building is, of course, measurement. New research by National Research Council Canada on Durability and Climate Change makes the point that sustainable building is increasingly reliant on proven data around the expected service-life of a building’s materials, components and assemblies. As well as developing future-looking climate data based on over 660 Canadian locations, the initiative led to rewriting Canada’s building and infrastructure codes and standards while introducing mandatory durability guidance for the first time.
As the anticipated effects of climate change take shape, the focus is on building structures and envelopes that are not only resilient at their inception but continue to perform in the long term. Our facades will not only need to be more resistant to extreme weather while reducing operational carbon, they’ll also need to be more durable over time, with longer lifespans that get the most mileage out of their embodied carbon.