Haf shares how traditional materials can shape a low-carbon future
Sustainability by Lead Consultant, Haf Roberts
New ideas and technology are continually moving things forward in the world of sustainability. The latest example proves that tech companies are constantly innovating in the search for more sustainable solutions to the climate change problem. Sheffield-based earth4 Earth announced this week about the bricks they’ve produced that can store carbon.
Not only does the brick capture carbon dioxide (CO₂) from the air but no CO₂ is produced in the manufacturing process either, as the team has managed to avoid the high temperatures normally usedl in brick production. The idea is an interesting and useful one as the carbon cost of the construction industry is enormous. According to UNEP, the United Nations Environment Programme, the construction industry is responsible for nearly 40% of the world's CO₂ emissions – more than any other sector. So any solution that can reduce that cost is valuable, especially since the brick is able to remove CO₂ from the atmosphere and lock it in buildings for a long time.
While reducing carbon in the energy used within a building, (heating, ventilation and cooling, and lighting), this is only part of the story. When erecting buildings the materials themselves incorporate carbon, known as embodied energy. For example, the most commonly used materials on site are concrete, steel and brick, and there is an environmental cost to extraction and disposal when considering their impact over time.
This latest discovery will be an important contribution to reducing the footprint of the brick industry, and as they can be reused or crushed into fertiliser at their end of life, they also contribute to the circular economy.
While welcoming this new initiative, especially since construction companies are so fond of building houses with bricks, it makes me wonder what other materials can meet the demand, and which are already in use. In the search for new and innovative materials, we are in danger of forgetting that traditional methods of building construction already exist and are tried and tested over centuries.
On a recent trip with Lafan to the Centre for Alternative Technology (CAT) in Machynlleth, I was reminded of the importance of simple, durable materials that have proven their robustness over centuries and world-wide. The WISE building amphitheatre incorporates layers of compacted soil into a beautiful rammed earth wall, which reminds us that raw materials are literally beneath our feet. There are also renewable crops such as wood, hemp and straw, and locally sourced materials such as soil, slate, lime and stone which have proven their value over time and tend to be less harmful to the environment. They’ve hitherto been overlooked in the construction industry, but with the need to reduce carbon and environmental impacts there is a growing interest in their use, as well as a necessary revival of the traditional skills of working with them.
A prime example of the value of these materials can be seen in the University of East Anglia Enterprise Centre where straw and reeds are used as cladding, earth walls, clay plaster and fibre made from nettles are incorporated into the fabric of the building.
It is of course innovative in terms of their use in a modern building, but their original use goes back centuries. Not only is there less carbon in their manufacture, resulting in low embodied energy, but the building promotes the traditional methods of cultivating indigenous crops and rural skills that could otherwise disappear. I believe it's a beautiful design as well as the fact that it's a unique and environmentally important building, because it has so many really innovative methods to enable the use of natural materials to be transformed into a light and airy modern building. Quite a feat and a credit to the architects, Architype.