National Geographic’s recent video on Concrete Canvas shelters went viral, as nearly 4.8 million YouTube viewers saw how quickly a sturdy structure could be raised when air is blown into wetted, cement-covered cloths. So we caught up with Peter Brewin, director of the U.K.-basedConcrete Canvas company, to get the story behind the innovation.
Concrete Canvas shelters can be set up rapidly. Photo courtesy of Concrete Canvas Ltd.
Can people buy the Concrete Canvas shelters now?
Yes, our shelters are available from different distributors in different territories. We have a distributor for the U.S. as well as other places.
How many Concrete Canvas shelters are out there?
Not a huge number. We’ve been growing very quickly, and our focus has been on the Concrete Canvas material, which in the U.S. is called Concrete Cloth. This is being used in a whole range of applications—primarily in civil works, for things like stabilizing slopes and lining water channels.
We will still produce shelters if buyers want them, but we haven’t put a lot of focus on that. A few have been bought by militaries.
How much do the shelters cost?
It depends on the volumes [of the order], thickness of the material, and your location. We supply most of the world from our U.K. plant, and the Concrete Canvas costs between 15 and 40 British pounds per square meter, in the U.K. ($23 to $60). For the U.S. we have a licensee: Milliken.
A Concrete Canvas shelter would cost 15,000 to 20,000 pounds, in the U.K., for a one-off ($23,000 to $30,000), but the price steps down if you are buying volumes.
Concrete Canvas shelters are blown up quickly. Photo courtesy of Concrete Canvas Ltd.
Concrete Canvas shelters can be surprisingly inviting inside. Photo courtesy of Concrete Canvas Ltd.
What are some examples of how the shelters are used?
There are many interesting projects with the Concrete Canvas material, including one in Chile where they are installing a gold mine at very high altitude: 5,000 meters (16,400 feet). On one side of the valley there is a glacier, and they wanted to prevent the melt runoff from going into the mine tailings [and picking up toxic material], so they built intercepts out of our material to carry water below. These are very difficult conditions to work in, where workers can only put in five hours a day because of the low oxygen, and our material is much lighter than alternatives, so it was easier to work with.
Most of the shelter projects have been military. We supplied shelters to the U.S. military for tests, which sent some to Okinawa, Japan. We have also supplied the Swedish, Dutch, and [United Arab Emirates] militaries, most of these for tests. The Swedes put one on a range and tested it against mortars. They were quite pleased with how it performed.
What about humanitarian applications?
We haven’t sold a huge number to NGOs [nongovernmental organizations]. We put quite a lot of effort into that early on, but we’ve had real difficulty. It’s partly the political element, because people don’t want to put up a semipermanent building for a crisis; they want to believe a refugee camp will go away soon. NGO customers also want a very large number of shelters if there is a crisis, but that is very difficult for a small company to supply.
NGOs would often want us to secure the funding, so we would have to get a donor involved, usually a government, so it was going to take an awful lot to get into the aid sector. We still think the shelters are really cool, and there’s a lot of potential. But right now we are focusing on the material.
There is a lot of interest for hurricane shelters, and we’ve got a test project to evaluate that and other applications this summer [in the U.K.].
A channel is lined with Concrete Canvas, to direct glacier melt runoff away from a mine site in Chile. Photo courtesy of Concrete Canvas Ltd.
Can you take us through the history of Concrete Canvas?
Eight or nine years ago, Will [Crawford] and I met doing postgraduate degrees in industrial engineering at Imperial College London and Royal College of Arts. There was a design competition run by the British Cement Association, and we really liked the idea of making efficient shelters very quickly.
To make that work we had to develop a Concrete Canvas material, which we could make dry in a thin layer, wet in an uncontrolled way, then have it set without cracks into a reliably strong form. That was a remarkably difficult thing to get right.
Our original business plan was focused on the humanitarian sector, so we went to Uganda and got very positive feedback. We won a lot of business-plan and design awards that helped fund the start-up, got some government funding and private-equity investors, and borrowed a derelict factory. After another round of funding we set up a production line in south Wales.
About five years ago we made our first sale, to the British military, to protect sandbags in Afghanistan. They survived a lot longer [than untreated sandbags] in a firefight. In our range demonstration, we showed that a sandbag wall covered in Concrete Canvas stopped 1,100 machine gun bullets.
Then we saw the material was really useful in construction. It can be set up about ten times faster than other methods. Instead of pouring or spraying concrete that has to be 50 to 150 millimeters thick (2 to 6 inches), our material is 8 millimeters thick (0.3 inches) for most applications. Laying slabs of concrete by hand is very slow and labor intensive, and spraying concrete is messy. Pouring concrete requires formwork.
Another interesting project was [when we covered] a pipeline in the Middle East; they dropped our material off a boat and divers installed it under water. It solves a problem in a totally new way. We also do a lot of slope stabilization. You just hang it off a crane, roll it off like carpet, then pin it.
Concrete Canvas is rolled off a crane to stabilize a slope. Photo courtesy of Concrete Canvas Ltd.
Concrete Canvas is rolled up like cloth. Photo courtesy of Concrete Canvas Ltd.
Is Concrete Canvas a green design?
Concrete is not the most carbon-neutral material. You use a lot of energy to make it, and when it sets, it releases carbon dioxide. But the advantage of our material is that you are using about 10 percent of the mass of alternatives, so you are emitting less carbon dioxide and saving on transport emissions. It is less bad than other ways of solving that problem.
The mixture we use also has a very low alkali capacity, so if you use it in a watercourse you do less damage to aquatic organisms.
Do you think your story has resonated so well because it is an example of “thinking outside the box” in our built environment?
Yeah, we tick that box pretty clearly. We’ve got several patents on the technology, and it’s a completely new way of using concrete.
It can be hard to convince engineers to use it the first time, but once they try it we normally get a lot of repeat orders.
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