Thatch-covered Enterprise Centre may be the world's greenest building
Not long ago the American plastics industry and the American Chemistry Council were at war with the US Green Building Council over the fact that they would even consider that plastics were not green. But they are fighting a losing battle, as those few architecture firms that actually care about sustainability try and build with more natural, bio-based materials. They would absolutely go into shock if they saw this harbinger of the future, the Enterprise Centre at the University of East Anglia, which Ben Adam-Smith says " might just be the most sustainable large building ever constructed in Britain."
Passive House +/via
I almost went into shock myself when I saw it on Passive House +; we don't see a lot of thatch in North America and I have never seen it used on walls. Not only that, it's prefab thatch; Ben Adam-Smith writes:
[Contractor] Morgan Sindall proposed the idea of off-site manufactured thatch panels that could be delivered to site and lifted into place. Working together with master thatcher Stephen Letch, they created a sample on site and mocked up how the panels would be fixed. Then, three hundred panels were fabricated at a local joinery shop and sent to Stephen's barn to be thatched. Morgan Sindall's James Knox says: "Normally over the winter period he doesn't really have much work on. We gave him and four other thatchers a couple of months' work while it was wet, windy and snowing outside. He was working in the warm, pre-thatching our panels off-site."
Passive House +/via
The building is designed by TreeHugger favourite Architype to some very tough targets: "70% bio-based materials, a threshold for embodied carbon, passive house certification, a Breeam Outstanding rating, and local sourcing and supply of materials." Passive houses can be very foamy because they need a lot of insulation, so there are some perhaps conflicting goals here.
Passive House +/via
Gareth Selby, an associate at Architype and passive house designer on the project, says: "Life cycle carbon was one way to sum up the operational carbon and the embodied carbon. Everything was assessed with that attitude rather than just looking at how good is it for passive house. It was bringing the two together."
The Passive House standard sets really tight limits on air changes, and I would have thought that they would have trouble achieving this with these natural materials, but evidently not; the air tightness layer is nothing more than OSB (Oriented Strand Board) with special tapes on the joints. They hit 0.21 air changes per hour, which is pretty spectacular.
But what really is so remarkable is the materials palette. A few years ago I got into a big bunfight when I suggested that there should be a version of Michael Pollan's Food Rules for buildings, which included not building with anything your great-grandma wouldn't recognize as a building material, that you can't picture in their raw state or growing in nature, or that you couldn't pronounce. I wrote:
I think we have to learn from what has happened in the food movement. That's the way people are going; they want natural, they want local, they want healthy and they reject manufactured chemical products. Twenty years ago every food manufacturer talked about the benefits of technology: Transfats make food cheaper and better, High fructose corn syrup has all kinds of advantages. Now even the biggest companies run from these, the vinyls of the food industry.
We are never going to get rid of all these chemicals and plastics from green buildings, anymore than we are going to get rid of all additives from food. Some have very useful functions and some, like vitamins in our diet or plastic sheathing on electric wiring, are even good for us. That doesn't mean that we shouldn't try to minimize their use and where there are healthy alternatives, chose them instead. I suspect that pretty soon, that is what your clients will be demanding.
The Enterprise Centre looks almost edible. I am still shocked. Forget being the greenest building in the UK; it might well be the greenest building anywhere.
Lots more images and technical details at Passive House +, and more Architype on TreeHugger in related links below. Legend to materials palette above: