Clare Whitney from Clayworks explains how clay plasters are made, their applications and why we might choose them over other wall finishes.
Interview with Clare Whitney
Clare Whitney has been working at Clayworks since 2009. The founders of Clayworks were specialists in cob building, even writing a book about it, and used clay onsite as a sustainable building product.
Clayworks now manufactures natural clay plaster, having spent two years creating a consistent and tested product that can be ready mixed and made available to anyone in the world at any time.
Clay is an ancient building material
Clay is one of the most naturally abundant minerals. Clare says that clay blocks and clay building methods are being rediscovered all around the world as a sustainable material with relatively low carbon intake. Clayworks focus on the application of clay as a plaster.
Clay plasters finish the interior walls of buildings
Clay plasters are a mixture of clay subsoil, aggregates and some natural form of fibre, with clay acting as the binder. Clay absorbs moisture, so water intake is critical; too much or not enough affects the consistency. Clare explains that Clayworks comprehensively researched different clay minerals to get the mixture absolutely right, so that the clay will not crack or “dust”.
Clay plaster differs from other wall finishes in several ways
Clare says it’s hard to describe the aesthetic, as you really have to see and feel and sense them, adding, “It’s a completely different feeling to walk into a room with clay plasters.”
Advantages of clay plaster include:
|A different aesthetic:
|• The patina is earthy and very soft
• A slight texture gives depth
• Clay doesn’t set, so you can create patterns and textures
|More sustainable than most other wall plasters:
|• Clay is a naturally abundant raw material
• It doesn’t have to be quarried
• The processing of clay plasters is minimal
• Apart from transport, there’s relatively little embodied carbon
|Numerous health benefits:
|• Clay plaster helps regulate the moisture inside a building
• Helps mitigate allergies and asthmas
• Helps offset the effects of formaldehydes and indoor pollutants
|The robustness of the material:
|• The product is scientifically tested
• Proven finish and durability
• Transportable and widely available
Clay plasters work with any type of construction
Clay plasters are now used all over the world in cities and in steel and modern buildings. However they have typically been used a lot in straw bale constructions and buildings with a lot of timber, due to their moisture-absorbing properties, and also in Passivhaus and other buildings where sustainable building products are key.
Furthermore, clay plaster helps to absorb odours and has very clear acoustic advantages, making it ideal for use in bathrooms and kitchens.
Materials can be beautiful as well as functional
Although their clay plasters were originally marketed on sustainability and health credentials, Clare says designers and architects have adopted them for their aesthetic qualities.
Clayworks’ plasters are now being supplied to customers all over the world; Clare attributes this success to their ease of use and the fact they can be trusted to stay on the walls and hold patterns, sculptures and shapes. Commercially their clay plasters have been used to fit out of well-known chain restaurants and public buildings.
You don’t need to paint clay plasters
Clare makes the point that although their clay plasters are a little more expensive than other wall finishes (starting at around £20 per m2), the overall cost is probably similar because:
- You never need to paint them
- They are through-pigmented, so you won’t notice a discolouration if they become chipped
- They’re easily repaired
Part of Clayworks’ research included coming up with a very comprehensive range of colours using natural mineral pigments. Clare explains, “We make colours in a fairly infinite mix. We’re always making up colours to people’s specifications…we can do a lot of turquoises, blues, greens and we’ve even done pinks and purples over the years.”
Different types of plaster have particular uses
Clay plasters are ideal for internal walls and ceilings throughout a house. The only areas to avoid would be wet rooms and exteriors, where Clare would recommend lime plasters, as they are more water repellent.
Clay plasters can also be used for feature walls and fronts of other surfaces such as kitchen interior bars and similar furniture-type applications.
If you can plaster, you can use clay plaster
Clare says you don’t need specialist skills as clay plasters are applied like any other plaster; it just takes a little longer because the clay is a slightly different consistency.
There is a series of different layers and depending on the substrate, you would need different binders, which Clayworks supply. A base coat and topcoat then follow.
Any good plasterer can use their clay plasters to achieve a plain finish, and artisan plasterers would be able to create specialist textured or sculptural finishes.
Self-builders can learn how to use clay plaster
There are lots of resources and support available:
- Call the Clayworks technical team who can talk you through every aspect of how to apply the clay; the services, substrates, primers and the entire plaster build-up.
- Visit Clayworks’ website for techniques and tips.
- Clayworks offer one-day training courses for professionals and novice plasterers.
- Self-help resources, such as Using Natural Finishes, can help you learn about the process of applying clay and lime.
- There’s a network of recommended professionals who have been trained by Clayworks.
Find out more
Visit the website of Clayworks