As promised (see last week’s blog), this is the first of a series of blogs looking at “What’s next for Construction?” After this, we’ll be investigating, amongst other subjects, modular construction, the internet of things, drones and exoskeletons, but now let’s turn to the fascinating (and it is fascinating) world of green design and construction…
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What do you think of when you think of “green” construction? Possibly some sort of Hobbit-like home, with turfed roof, all the latest eco-gadgets, rainwater recycling, ground source heat pumps and the like? Or something more akin to the way in which Atkins and others are using organic matter (mushrooms, etc.) to make building materials – as reported in one of our earlier blogs?
What’s fascinating when you start to explore this new world is just how much of it is already well known. One of the best summaries of green construction I came across listed a dozen “sustainable construction technologies.” These included: solar power; biodegradable materials; “green” insulation (old newspapers, denim, etc.); smart, energy-saving white goods and other devices; sustainable resourcing (i.e. re-using and recycling materials); zero/low energy design; electrochromic smart glass; water efficiencies (rainwater harvesting, etc.); sustainable (e.g. non-toxic) indoor technologies; self-powered buildings; cool roofs; and the rammed brick.
Several of these are not new. The “rammed brick” – essentially a forcing together of clay, gravel and concrete – “is an ancient construction technology which has lately been re-introduced to cater for the demands of environmental sustainability.” Recycling materials to make a form of brick or construction material has been around for a long time. The addition of cow dung to adobe bricks, as well as other natural materials such as straw or rice, has been common for centuries. Unfortunately, as these eco-evangelists discovered, this is not a particularly quick or efficient process.
While faeces may take a long time to turn into bricks, another human waste product looks like it might be a better bet. Researchers in South Africa have made bricks from urine, which has several advantages over conventional kiln-fired bricks. To quote from an article from earlier this year:
“Human urine, loose sand and a bacteria that produces the enzyme urease are combined in a brick-shaped mould. The urease triggers a chemical reaction, breaking down the urea in urine, while producing calcium carbonate — aka limestone, the main component of cement. This solidifies the bricks, and the longer they're left in their moulds, the stronger they get.”
Because these bricks harden at room temperature, “they could be a real alternative to traditional bricks, which are heated at temperatures of more than 1,000 degree Celsius, producing huge carbon dioxide emissions.”
While many of the technologies on the list above are fairly well known, there are some that are really new. I was particularly interested in the concept of electrochromic smart glass. This uses “tiny electric signals to slightly charge the windows to change the amount of solar radiation it reflects.” When incorporated into a building’s control system this allows you to choose the amount of solar radiation to block and can therefore save a lot of money on heating, ventilating, and air conditioning.
I would encourage everyone to take an interest in green design. Apart from the fact that it’s interesting for its own sake, with our increasing awareness of the damage we’ve done to our ecosystems over the last couple of centuries and the imperative to protect our environment for the generations to come, it’s a subject that is only going to grow in importance.
Chris Peace, MD, Peace Recruitment