Why Buildings Shouldn't Be Shaped Like Letters

Thinking about embodied carbon changes the way you think about design.

O, H, L and C shaped buildings in London
O, H, L and C shaped buildings in London.

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A decade ago I was president of a heritage preservation organization in Ontario, Canada, pushing the idea that "heritage is green" and there was much to learn from old buildings—they weren't relics from the past but were templates for the future. I noted that in the world before electricity, buildings were shaped like letters so everyone was close to a window for access to fresh air and natural light. I wrote a Treehugger post at the time titled "Architects: Go Back to the ABCs and Design Buildings Like Letters Again," under a drawing showing buildings shaped like H, L, O, C or E, many of which can be seen in the photo of London above.

As an architect, I thought we should do more of this, writing:

"Today, the engineers would say that the heat loss or gain through so much exterior wall would use far more energy than would be saved using daylight and natural cross-ventilation. They would say that the most efficient building would maximize the floor plate and minimize the perimeter, the size of windows and the amount of air change. That is what they did in the 70's and how we got a lot of toxic buildings. But we also have very good insulations now, and can perhaps afford a little more perimeter for a lot more natural light and air. There is probably a compromise to be found between filling our buildings with high-tech "green gizmo" solutions and simply building with healthy materials, lots of light and lots of fresh air."

Much has changed in the decade since I wrote that. For most of the last 50 years, we have worried about energy consumption, but now we worry about carbon dioxide emissions, which is a very different thing. Buildings are more efficient, the electricity supply is cleaner. And in a new building, the upfront carbon emissions from making the materials and constructing the building can be bigger than the carbon emissions that come from operating the building.

Embodied Emissions as total
ACAN with information from Sturgis Carbon Profile

In some cases, the upfront emissions can be as much as 80% of the total lifecycle emissions, and there is a real time-value to carbon. The big burp that happens at the beginning comes out of our carbon budget now, which is why I keep using the term "upfront carbon emissions" instead of embodied carbon—it's happening now. But I also can't just say "let's have a little more perimeter for a lot more natural light and air."

Much of the embodied carbon and upfront emissions are related to the choices of materials, but in a recent essay titled "Reducing embodied carbon isn’t all about materials," Frances Gannon of Make Architects looks at other issues that affect the amount of embodied carbon in a building, including form factor:

Form Factor
Make Architects
 "...the ratio of heated floor space to heat loss envelope (ground, walls and roof) is often discussed in terms of minimising operational carbon but it makes a huge difference to embodied carbon as well. The simplicity and efficiency of a building’s form is key, as increasing complexity almost always increases embodied carbon. Each recessed entrance, cantilever, inset balcony and facade step comes at a carbon cost and we designers must be rigorous in using these only when essential."
Vancouver house by Bjarke
We can't keep doing this/ Vancouver House by Bjarke. Lloyd Alter

We have discussed this before, complaining that every jog, bump, and step causes more heat loss and thermal bridges, with Bjarke Ingels' Vancouver House as the poster child for how you should not design buildings. It's why we use Bronwyn Barry's hashtag #BBB– "Boxy But Beautiful" for simple but elegantly proportioned buildings.

When I wrote my post a decade ago, I argued for a compromise between building form and access to light and fresh air. Gannon does as well, recognizing the trade-off.

"Of course, our designs must always respond to context and scale, and must always provide great daylight, ventilation, and outdoor spaces for occupants’ wellbeing, but we must do this in the most efficient way possible to reduce embodied carbon."
embodied carbon in facades
Frances Gannon/ Make Architects

Gannon shows how much difference it can make, going from a round building to an L building to a C building. There is roughly 75% more facade on the C building while enclosing the same floor area.

Terry Thomas Building Seattle
Terry Thomas Building/ Weber Thompson/ Seattle. Lloyd Alter

Gannon doesn't include O buildings, like every 19th Century building in London or my favorite "New Old" building, Weber Thompson's Terry Thomas building in Seattle, with its big courtyard. I called it "a breath of fresh air. It is what a green building should be: not just about energy, but about being healthy and happy as well." It's hard to imagine a building form with more surface area per square foot of space.

Lipstick Building by Philip Johnson
Lipstick Building by Philip Johnson. James Leynse/Corbis via Getty Images

Who would have imagined that Philip Johnson, notoriously disdainful of green and sustainable building, would demonstrate how to minimize surface area with his Lipstick Building in New York City. But as noted earlier, thinking about carbon is very different than thinking about energy.

simplicity firsst
Frances Gannon/ Make Architects

Most architects aren't thinking about embodied carbon, building codes don't take it into account, and many zoning bylaws actually encourage steps and setbacks that increase surface area and the concomitant increase in upfront carbon. But it's the architectural issue of our time, and you can't go wrong following Gannon's advice, where she notes that it's not just about material choices:

"Key design moves at the start of the project will make the biggest difference: reusing existing buildings where possible, keeping new building forms simple and efficient, ensuring structural efficiency, keeping structural grids small and considering how the facade interacts with the frame are key contributors to the overarching principle of using less. Then as the conversation moves to materials, we’ll have the best chance of meeting ambitious embodied carbon targets."

Or as we have written on Treehugger, go for radical sufficiency. What do we actually need? What is the least that will do the job? What is enough? And also radical simplicity–everything we build should be as simple as possible. Gannon does a better job of putting it into architectural form, and her essay should be required reading for architects everywhere.