Can earth building scale up to the mainstream? – ClayWorks and clay plasters

January 16, 2014

NOTE: Images in this archived article have been removed.

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Academic Gill Seyfang wrote in 2009 in a piece about natural building that such materials and techniques will only make the step across into the mainstream if they succeed in “scaling up the existing small-scale, one-off housing projects to industrial mass production”. Over the next 2 days we’ll be looking at 2 aspects of earth construction, cob and clay plasters, and their potential for scaling up.

We start today with Adam Weismann and Katy Bryce, who founded Clayworks, an "award winning UK manufacturer and provider of services and products in unfired clay", who provide "a beautiful range of backing coat and through-pigmented top-coat clay plasters".  Walls good enough to eat. But might they become a mainstream building material? 

You’ve been involved in earth building for some time now.  Where do you see it in terms of its penetration into the mainstream?

Our experience is that mass earthen wall building is more difficult to transfer into the mainstream due to the price of labour vs materials. Earth walling systems are generally labour intensive which makes them expensive unless being executed by the homeowner or a volunteer based programme. This tends to keep earth walling as a specialised, niche way to build walls. Our attempts to bring mass cob walling into the mainstream were thwarted by costs, that is why we decided that the best way to get unfired clay into buildings was through the route of finishes, which could be applied onto more conventional materials.

You recently launched Clayworks as a business making and selling pigmented clay plasters.  What has that experience taught you about the potential of these materials to go mainstream? 

Our past and current experiences are that it still remains tough to convince the mainstream market about the value of using unfired clay in buildings. Cost still remains a challenge for us – how can we compete with our direct competitors such as British Gypsum and La Farge? There is still a lot of education that needs to be done to convince large scale and small-scale developers about the durability of using clay plasters. A large portion of our work is in this awareness raising/education.

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Although programmes such as the dreaded Grand Designs have taught the public that natural materials such as clay and straw are viable options for building a home, many people remain sceptical and unaware of the potential for building with these beautiful and functional natural materials. They are also held back sometimes due to the outdated perception that they are quirky, ‘rustic’ and unreliable. Until real economies of scale can be reached, cost will always be the issue.

With most mainstream building projects cost is the main deciding factor about which materials to be used. Where we have seen success into penetrating the market, is when our clay plasters (a ‘luxury’ product) can be used alongside conventional materials. People can choose to spend their money on the really visible part of the house and achieve the functional, aesthetic, environmental and health benefits that most natural materials bring. This was therefore a key prerequisite behind the design of our clay plaster systems.

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What do you see as the key obstacles for natural building materials becoming a more commonplace part of the construction industry?  Are they always bound to remain in a niche? 

Firstly, the technical difficulty of standardising materials that are by their very nature ‘local’, ad hoc, variable and inconsistent. To sell a building product on the open market you need to have tests and technical data that tell your customers that this product will behave in exactly this way every time. It was a huge challenge to develop a clay walling plaster to this level of standardisation when it had grown out of a philosophy which embraces the use of materials that encapsulate the soul of a locale. Everything about creating our product was a lesson in making compromises around these core beliefs, set a against a stronger desire to bring the beauty and functionality of clay to a wider audience and our belief in the power of  building materials to change and enhance  peoples lives – from the physical to the more esoteric levels.

Secondly, as touched on above, the challenge of economies of scale to produce a product that is affordable to a wide variety of customers. Our product remains more expensive than the standard walling finishes such as those made out of gypsum and cement. However, due to the way clay walling plasters and most other natural building products function (regulation of humidity and temperature in a space etc) these costs are mitigated against the costs of health, environment and building longevity. It takes a very aware and environmentally responsible individual to value these long term cost savings and to set the long term gains against the intitial cost. 

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Thirdly, this brings us back round to education and the need to engage with homeowners, developers, designer, architects, builders, the general public about the very real need to build environmentally responsible buildings that not only have a lighter impact during their construction but also in the way they function in the long run. Not just greenwash.

Lastly, developing a skilled pool of labour who are trained in producing environmentally responsible buildings out of natural materials to a very high standard within a financially viable business context i.e tension between artist/craftsperson vs businessperson. 

Natural building products can be brought out of their niche, but only with certain compromises. The purest approach will always remain philosophically bound, for its very essence does not allow it to expand and filter outwards. The purely cost-driven, conventional approach will never allow room for natural building materials and techniques that compromise the profitability of the project. The gap must be bridged between the two. Hopefully, a product such as ours and other similar ones on the market, are going someway to laying the foundations for this bridging. 

What construction projects have you seen recently that have given you most inspiration?

Anything built out of natural materials – unfired clay walls, floors and finishes, strawbale, stone, wood, thatch – built on a large scale: 

  • Studio Mumbai Projects (an architectural/craftspersons firm in India) who create a fantastic synergy between building vision and execution due to the fact that the designers and builders are one and the same firm.
  • School in Bangladesh by German architect named anna (can’t remember last name!)
  • Japanese temple architecture
  • National Trust visitors centre in strawbale – Lake District, UK
  • Cobtun, Totnes –  Paul and Ivana Barclay –  a beautiful testimony to a family with no experience of building with cob to create a unique and indvidual work of art as a home.
  • Econest projects in Santa Fe, USA
  • The Globe Theatre – Southwark, London – a beautiful building made out of natural materials that nestles softly amongst the London skyline
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With the green building world becoming increasingly focused on performance (i.e. Passivhaus) at the expense of the localness and low impact of the materials, how might we change that? (if indeed you agree with that statement?) 

We agree with this statement! Our core philosophy has always been to use low impact, functional materials – making a building work from the bottom up, before using add on technology (which does not have a low environmental impact to make) to make it function better. To change this, it comes back to education.

The most important people to educate about this are those designing our homes for the future. An example of this is the use of unfired clay to regulate humidity and temperature in a building. The Passivhaus concept is fantastic, but many people get caught up in making a building perform better with add-on technology, and using materials such as plastic sealing tapes throughout the entire building. They fail to think about the impact of these products on the environment from their production to their afterlife, whilst thinking their conscience is clean because they are using very little energy to heat their building. Our other bugbear about Passivhaus and the failure to consider the use of natural materials in their construction, is the fact that a sealed building envelope is created holding a veritable soup of off-gasing building materials – not good for the health of the inhabitants or mother earth.  

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Most ‘natural building’ projects tend to be one-off self-build projects.  On larger developments, with larger economies of scale, what do you think is possible with sufficient imagination and determination?  Is natural building always going to be the most expensive option?  

Anything is possible with the right intention. It would take a collective of very determined individuals who all hold a strong environmental vision. We see a larger development being created through the use of intermediate technology, such as a cob block maker to turn local clay soils into building blocks, a min-miser for milling local timber, large paddle mixers for making mortar etc. A strong core of skilled leaders leading a collective of physically fit, enthusiastic people working towards the same vision.

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The project would also need strong financial leadership to ensure that it remained commercially viable.  A project such as this would need to be situated somewhere in the world where there were plentiful local materials that could be used for construction materials. As in the past, the designers of these buildings would need to be skilled in understanding how the local materials could be used to their best effect. 

What role does design play?  Most houses in the early ‘cob revival’ were what many people dismiss as ‘Hobbit houses’.  What can design do to make cob funky, modern and desirable, and who is working in this field already would you say? 

To bring earthen buildings more into the mainstream and make them more modern and desirable, design is absolutely essential. Not just for how the building looks, but also in how it functions – using the materials to do what they are good at, and in the environment that they are situated (local climate etc) and creating design details that ensure their longevity and hence the longevity of the structure.

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Natural buildings will grow in viability once people gain confidence in a legacy of optimal functioning and longevity. For people that we see working successfully in this way, see point 4 above. Two astounding people (an architect and master timber framer) who have really managed to bring together excellent design with the use of local, natural materials, are Robert and Paula Baker-LaPorte in the USA (EcoNest). They design exquisite earthen buildings of all scales, that have exemplary design detailing. They look highly modern and classic, but remain earthy and wholesome, so can appeal to a wide audience of people. They have taken natural building to the next level in our eyes.

You’ve spent a lot of time in and around earthen buildings.  If you had to summarise how they are different, how the experience of being in them differs from conventional building, what would you say?  What was it about earth buildings that you fell in love with however many years ago it was that you fell in love with them? 

Aha, a very long and intense love affair indeed that is set to continue into infinity! Where to begin. 

  • The way the walls absorb sound
  • The ability to create rounded, sculptural shapes as well as very linear, angular lines
  • Living inside of nature – the ground beneath your feet rearranged to create walls, floors, plasters
  • Earthy colours and pigments pleasing to the eyes and senses
  • Healthy indoor climate – humidity and temperature regulated
  • Walls warm to the touch
  • Walls and floors that remain alive and in dialogue with their environment – unfired clay materials never chemically set, they just harden, meaning that they remain fluid within the realms of aliveness
  • The sheer vastness of different ways, methods, styles, techniques of building with this one ubiquitous material around the world, and the way they tell the story of the people and the places in which they are situated

All the above points come together into one elating feeling within the sub-conscious mind whenever we walk into a clay house!       

If natural building and its vision is to truly scale up, what skills, observations, expertise and shifts in thinking do we need to bring into the movement?  

  • Compromise, whilst maintaining core values and ethics of natural building.
  • Expertise in natural building skills and trades of a very high standard, inspired and grounded in traditional crafts and building skills  – arranged through the traditional apprenticeship scheme (training with masters for years instead of months)
  • Marrying together expertise in natural building skills with strong business training to make financially viable businesses that make commercial sense

Be brave and take your vision out into the ‘conventional’ mainstream building world i.e stop preaching to the converted. If you believe in what you do with a strong passion and you have sound technical grounding behind it, you will be amazed at how appealing this can be to even the most conservative amongst society.

Adam and Katy founded ‘Cob in Cornwall’ which is now called ‘Clayworks’.  They are the authors of Building With Cob: a step-by-step guide and Using Natural Finishes: Lime and Clay Based Plasters, Renders and Paints – A Step-by-step Guide.  They also work as earth building/clay plastering practitioners.  

Tomorrow we head to East Devon to visit the the largest cob house ever built and to hear what lessons it can offer for the scaling up of cob construction. 

Rob Hopkins

Rob Hopkins is a cofounder of Transition Town Totnes and Transition Network, and the author of The Transition Handbook, The Transition Companion, The Power of Just Doing Stuff, 21 Stories of Transition and most recently, From What Is to What If: unleashing the power of imagination to create the future we want. He presents the podcast series ‘From What If to What Next‘ which invites listeners to send in their “what if” questions and then explores how to make them a reality.  In 2012, he was voted one of the Independent’s top 100 environmentalists and was on Nesta and the Observer’s list of Britain’s 50 New Radicals. Hopkins has also appeared on BBC Radio 4’s Four Thought and A Good Read, in the French film phenomenon Demain and its sequel Apres Demain, and has spoken at TEDGlobal and three TEDx events. An Ashoka Fellow, Hopkins also holds a doctorate degree from the University of Plymouth and has received two honorary doctorates from the University of the West of England and the University of Namur. He is a keen gardener, a founder of New Lion Brewery in Totnes, and a director of Totnes Community Development Society, the group behind Atmos Totnes, an ambitious, community-led development project. He blogs at and and tweets at @robintransition.

Tags: Building, cobb buildings, natural building, scaling up