Try your hand at building a cob studio

Need a garden office or a place for your teenagers to hang out? Build your own using the ancient cob's apparently not that hard to do!

Text: Noah Dugall
cob houses date back thousands of years

Yes, really, you can do this yourself..take some earth, clay, water, gravel and straw, mix it all up, and start shaping your shed. But it might be worth going on a course first...

If you hanker after a garden shed or outside room with a difference, why not consider building your own this summer - the lockdown isn't going to be a thing of the past for a fair ol' while yet? The ancient building technique known as cob is, according to Kate Edwards of Norfolk-based Edwards Cob Building, so easy that anyone can learn to do it. In four days. That's how long the Edwards' training courses are. Which to those of us who are not practical won't sound anywhere near long enough. 

'It really is straightforward,' says Edwards, who lists the many merits of cob building: it doesn't create CO2 emissions, it uses the earth it has displaced, it doesn't need concrete, and the buildings are inherently warm.

If your cob building is going to be the size of a generous garden shed, you probably won't need planning permission, but do check with your local planning department. Here's a rough outline of what you would need to do, Blue Peter spirit to the ready:  Find a spot in your garden for it, mark it out and dig out a trench about 2ft deep. You will need sandy rather than clay soil, a mix that's 80 per cent sand and 20 per cent clay.

Okay, so you've dug your trench. Put the subsoil to one side, while you fill in the trench with gravel topped with limecrete.  Next build a brick plinth about 18 inches high to mark out the perimeter of the building, and then you're ready to start mixing up the cob, which consists of the soil you dug from the trench, straw, clay, sand and water. The best way to mix up the cob is with your bare feet and a pitch fork (do keep those toes out of the way), and if you can rope some friends in to help, this will make the job easier and faster. Not to mention a barrel of laughs..

Learn with Edwards Cob Courses
Learn to build a cob house in 4 days...

When the mix has the consistency of soft plasticine, you're ready to start shaping your walls.. mould it in your hands and build it up slowly from the bottom of the brick plinth, leaving spaces for windows and a door. And do make sure the roof overhangs by 18 inches.  Leave your handiwork to dry for a few weeks, and you can plaster the outside with a lime render, and cover the interior walls with clay plaster, painted with a limewash. 

Well, that doesn't sound so hard does it. Edwards says a small cob project, such as building a garden room, will take around 5-6 weeks, and the costs really are minimal. The four-day course costs around £600, then materials will cost around the same. Obviously how you decorate the building, and what type of windows and door you choose will affect the price. If you want a cob building but you want it built for you, then you'll be looking at around £12-14,000 for a fairly simple design. 

Edwards says people from all over the country are keen to attend their courses, because cob building is fun, it achieves an incredibly environmentally-friendly and unusual extra space, and the building will be long lasting and weatherproof. 'Cob dates back a good 10,000 years, so it's stood the test of time,' she says.

And if house prices continue to be unaffordable for many groups of people, perhaps we'll see a return to cob houses on a large scale as a solution to the problem.