This Pringle-Shaped Shelter Is a Great Example of 'Design Efficiency'

The best way to build in a climate crisis is an ongoing discussion and in many of our discourses, I have noted we should be building as little as possible, regardless of the materials being used. I preach the virtues of sufficiency, efficiency, and simplicity, and often quote designer Andy Simmonds and journalist Lenny Antonelli about what they call design efficiency:

"Use natural resources extracted from our shared biosphere respectfully and efficiently to substitute for higher embodied carbon materials. Use as few materials as possible to achieve the design."

My new poster child for demonstrating the best in design thinking is a community shelter at Westonbirt, the National Arboretum, near Bristol in the United Kingdom. Designed by a partnership between architects Invisible Studio, led by Piers Taylor (known to Treehugger for a lovely long drop loo), and timber structure specialists Xylotek. 

According to the Westonbirt website, it is a shelter "for their committed coppicers, a permanent timber structure which will provide shelter from the elements, as well as store their coppicing equipment safely." Taylor tells Treehugger, "Yes, it started out as the coppice shelter then was renamed part of the way through the project as the community shelter. It is in the silk wood at Westonbirt which is a coppiced wood. Some of the timber was indeed coppiced—and it all came out as part of Westonbirt's management plan."

Coppicing is perhaps the most respectful and efficient way to harvest wood. Treehugger contributor Elizabeth Waddington describes it as "an age-old technique that involves harvesting stems from a tree while allowing it to remain in active growth. Many trees and shrubs can be coppiced by cutting them almost to the ground on a cycle...As an alternative to clear-felling, coppicing offers better solutions for our climate crisis."

Even in the most sustainably harvested forest, a big chunk of carbon emissions comes from the roots that rot after the tree is cut, which is why coppiced wood is possibly the perfect green building material. The building is "made from trees that were due to be extracted from Westonbirt's own collection as part of its routine woodland management cycle, as well as recycled old, aluminum signage from across the site." 

Then there is the second half of the Simmons/Antonelli definition, to use as few materials as possible. So the building is a hyperbolic paraboloid, described in Designing Buildings as being "pioneered in the post-war era, as a hybrid of modern architecture and structural engineering. Being both lightweight and efficient, the form was used as a means of minimising materials and increasing structural performance."

That's why Pringles, the "fake" potato chips, are shaped like that. According to Interesting Engineering, "The two opposing curves perform well together under tension and compression, which gives each Pringle some structural strength despite their relatively thin shape."

But this roof is not just about strength. "The distinctive and innovative hyperbolic paraboloid shape of the shelter will offer protection from the elements while offering important views through to the surrounding woodland."

Because hyperbolic paraboloids are "doubly-ruled." They can be constructed with straight structural members. They have not done that here. According to Xylotek, "Plywood jigs were used to enable the steam-bending process. Once steamed, the pliable oak laths were shaped over the jig and clamped in place to cool. These members formed the gridshell lattice components to enable construction of the roof." Volunteers assembled it with varying levels of skills. 

"The aesthetic appears to a certain extent ad hoc but it has been deliberately created this way to allow inclusive design and offer the groups who will use the shelter a space that is non-prescriptive. The community that uses the shelter will feel a sense of ownership, while those participiants involved in the build process have experienced the pride in making this project, with a postive outlook on what they can achieve next."

There are several reasons why this building is so special. Taylor and his Invisible studio "aims to be a different organization from a conventional practice" and explains:

 "We operate from a self-built studio located in a working woodland which we also manage as an ongoing forest enterprise alongside practice, and have pioneered a number of academic programs that rethink the relationship between design and making," says Taylor.

It is not a conventional building but one based on a form that maximizes material efficiency and gets the most out of the least.

It is not made from conventional materials. Instead, it's made from perhaps the most sustainably harvested wood you can get. 

And finally, when I want to discuss Pringles and hyperbolic paraboloids in architecture, I no longer have to use a photo of that rusting waterworks building by the highway in Hamilton, Ontario. I have many reasons to love the Westonbirt Community Shelter.