Shelter Publications: Roundwood Timber Framing by Ben Law
Roundwood timber framing: the greener way to build
The Ecologist - 19th October, 2010
Using our native softwoods and 'in the round' construction, this innovative technique results in beautiful buildings with high environmental credentials
In a clearing in our woodland at the Sustainability Centre, just beyond my window, Ben Law and his roundwood framers plus apprentices have been building a woodland classroom. It has been wonderful to watch it arise out of the woods and be a small part of the experience. Much of the timber has been sourced from our overstood plantations here. Years ago, when the centre was in its infancy, foresters working for the county council came to assess the woodland, left unmanaged for more than 50 years and damaged by grey squirrel and deer. They told us the best thing we could do commercially was to clear-fell the lot and replant. Today Ben and his crew have built us a beautiful building from this maligned timber. He tells me there is still enough suitable timber left for at least four more large buildings.
The classroom’s frame and its steam-bent roof rafters are made from Lawson's cypress, a softwood that is usually pulped for paper or chipped for biomass boilers. Ben had never built with this timber before but it is abundant here and he uses whatever is available on site whenever possible. He tells me the wood is a pleasure to work with. Each frame is individually constructed by hand in the woods and moved into position for the frame-raising. They sit on padstones, each carefully sited, and after raising they are anchored to the earth, literally. The floor joists are Douglas fir and roof shingles are western red cedar, another abundant fast-growing wood that can be substituted for oak. The cedar comes from the Cowdray estate, just over the border in Sussex, more famous for its polo.
The build itself – sited at the former HMS Mercury shore establishment, an ex-Royal Navy base that is better known for its bomb-proof, rather brutal 1960s buildings – is a beautiful landmark. It is a celebration space as well as a classroom, with a magnificent shingle roof that curves over the building like the hull of a great ship. The northern end holds an energy-efficient Rumford fireplace, surrounded by rammed earth, cordwood walls and a bench, plus an earthen floor sealed with linseed oil. The rest of the floor is boarded western red cedar. The walls are open to the elements (a design that allows for more lenient planning permission and building regulations) and the southern end opens up into a large veranda, soaring out into the woodland.
Bringing building back into the community
Beside their beauty and functionality, what characterises Ben’s builds is community involvement. Ben wants to relocalise building in two ways. First, he wants to use timber in the round, i.e. not planed in a sawmill, grown as near to the build site as possible. This minimises transport, uses a resource that is regarded as low value and is often pulped or burnt, and reduces the need to mill. He also wants to build locally himself and is actively training timber-framers from all over Britain and further afield to work in their own localities. He has an apprentice scheme running from his own Sussex woodland and also takes on trainees on individual builds.
Writing about roundwood timber framing, Ben has described all aspects of what is no less than a new architectural vernacular. He starts with how to choose appropriate trees to fell, explains how to lay the padstone foundations, describes the process of roundwood framing, and the jointing and pegging techniques (which differ from green-oak framing). Then comes the construction of floors, roofs and walls using natural materials like waney edge boards, cob and straw bales; and finally there are examples of seven very different buildings.
The result is that roundwood timber-framed buildings are beginning to appear and the planners and building control officers are learning to appreciate their high environmental credentials. One apprentice, Mark Alvis, now living in Canada, trained with Ben on the Woodland Classroom build for five weeks. Before emigrating, he raised the frames for a garden structure plus another small demonstration building at the Sustainability Centre.
Build it yourself!
There is no reason why more people with a reasonable grasp of carpentry can’t begin to experiment with modest structures before they go on to build their dream eco home. This way of building has already been applied to garden sheds, outhouses, workshops, compost loos, playrooms… The advantage is that we're surrounded by softwoods from overstood plantations such as Lawson’s cypress and Douglas fir, or coppiced products like chestnut, which can be cheaper to acquire than imported milled products. Ben built the Lodsworth Larder at two-thirds of the price of a conventionally designed and built shop.
Structural engineers have also calculated that wood in the round is up to twice as strong as milled wood, meaning we do not have to fell great oaks for structural strength, we can build with smaller-diameter roundwood. Our fast-growing softwoods are so often neglected because there is no longer adequate commercial value to justify thinning or felling them. Left to their own devices, they grow close together in light-deprived plantations that pull the long, straight poles skyward. Ben says these are perfect for roundwood timber-framing.
As climate change warms our temperate shores, our slow-growing oaks, traditionally used for greenwood framing, will migrate northwards. Ben is therefore keen to identify and test faster-growing alternatives. Besides finding new end uses for western red cedar, Lawson’s cypress, sweet chestnut and Douglas fir, Ben is also looking for more temperate-climate alternatives to oak and beech, such as swamp cypress (Taxodium distichum) and Robinia pseudoacacia. The later is commonly known as the Black Locust, a nitrogen-fixer, which is reputed to last ‘a year longer than stone’.
Ben is dedicated to finding viable economic markets for Britain’s overstood plantations. By bringing them back into production, he is not only inspiring a renaissance in sustainable woodland management, but also encouraging practices that produce greater biodiversity. Where coppice is brought back into rotation and overstood plantations are cleared and replanted, flora and fauna return. Orchids and rare butterflies are attracted to the restored habitat.
So if you yearn to build a cabin or workshop in your garden or a lean-to by the back door, before you buy milled timber from eastern Europe from your local wood yard, spare a thought for our native softwoods and consider building in the round. You’ll do more than craft a beautiful handmade structure, you’ll be supporting a renaissance in sustainable woodland management in Britain.
Maddy Harland is the editor of Permaculture Magazine and co-founder of the Sustainability Centre. She also writes a regular blog.
Read the original article on TheEcologist.org.