Earth Building UK and Ireland has produced a learning module on earth building for School of Specification. CEO Rowland Keable explains why we need a change of mindset to unlock the many benefits it brings.
What are the main types of earth building?
Earth structures can be classified in a number of ways: monolithic, masonry, or framed, while finishes can be flat, decorative or 3D. Monolithic structures include rammed earth and mass earth (also called cob and many other vernacular names), while masonry includes earth mortars (used with earth blocks, fired brick or stone), moulded or compressed earth brick and block and turf. Framed systems (also known as wattle and daub and many other vernacular names) start with a timber frame and lattice made from many different materials, such as cane, timber, rope, reeds etc, and filled with daubs of earth and fibre in different percentages, including light earth which is 50:50 clay and fibre by mass. It’s a big family of materials and processes, which offer solutions to many soil types and sequestered carbon from a range of plants. The naming system – mass, rammed, moulded, mortar, framed and finishes – is not a denial of vernacular knowledge, skills and terminology, but rather a simplification intended to clarify a complex picture.
What are the main advantages of earth building?
Earth construction is a highly adpatable form of building, which lends itself to many different soil types making it suitable for use with most local soils. That means looking at sites for the types of materials they yield and designing buildings which are suited to those materials and to a whole family of processes, structures and aesthetics unique to the site. Once built, clay manages internal air quality better than anything else, keeping humidity between 40 per cent and 60 per cent, which means no mould growth, poor conditions for the transmission of virus or bacteria, and the ability to sequester VOCs, purely due to the chemistry of the clay.
What are the most common misconceptions about earth building?
The introduction of coal into the supply chain brought with it fired bricks, burned lime and buildings with a coal fireplace in every room. Somehow this reliance on fossil fuels has been seen as a positive for about 300 years and yet, for so many reasons, it has actually produced very poor housing stock that requires mechanically active heating and cooling systems to try and compensate for poor building fabric and design. Probably the most common misconception is the idea that any other way of building is a step down. In reality, it’s a fantastic opportunity to design buildings that work with us, rather than in spite of us.
What are the obstacles to earth building being adopted more widely in the UK?
Simply put, ignorance and confidence. Ignorance of clay – how it works and the ways and systems to build with, and a lack of confidence in a robust supply chain, regulatory framework and trained workforce. In short, we have to turn the juggernaut that is construction a few degrees from where it’s currently heading – with a cargo of high emitting fossil-fuelled petrochemical products – towards a new destination of locally-sourced bio-comfort natural materials. Easier said than done, but that’s why we started an earth building organisation; to help bring willing minds to the task.
What advice would you give to any architect or client considering earth construction for a project?
Feel confident that you are doing the right thing. Reach out to people with skills; support them, listen to them. It’s not easy swimming against the tide, and it can be hard to meet the expectations of ‘normal’ ways of working, especially when you don’t have ‘normal’ financial backing. Shift your ideas about programme. Concrete may give more certainty, but it doesn’t make it right. Collaborate and enjoy the process. It doesn’t have to be a combative endeavour. Look at the materials you have and use them for what they do best. Not all earth is rammed earth. Remember you live in Devon not California, Scotland not the Mediterranean.
What do you consider to be the most interesting/successful examples of earth building in the UK?
In terms of sheer numbers the mass houses of the south west and the moulded earth block buildings of East Anglia are obvious signs of success. But when considering the stone buildings of Scotland, Yorkshire and Wales and the amount of earth mortars used, these are no less impressive. The longevity of all these buildings is very interesting and deserves a lot more attention by designers, developers and builders as well as regulators and funders. Recent research work on achieving current thermal regs using mass and light earth in the EU’s CobBauge project gives a glimpse of the suitability of these materials and processes for much wider and larger-scale use and shows the need and use of organisations like Ebuki to provide a voice for earth which has been missing for so long.
Join Unit 1 of Rowland Keable’s module on earth building FREE OF CHARGE at: www.schoolofspecification.co.uk/courses/earth-building
