Workshop on Building with Cob

uploaded July 22, 2002

In the summer of 2000, we had the opportunity to take a two-week intensive workshop on building with cob. A doctor in northeast Ontario, who works with Patch Adams's organization, was building a small, two storey, clinic out of cob and Linda and Ianto of Cob Cottage were teaching the course.
It was a most interesting and educational time.

clinic on Aug 6

This is what the clinic looked like on August 6. A team had arrived before us to prepare the groundwork - the site had been leveled, a stone foundation laid, sand and clay delivered to the site, water carted and stored in drums, poles to hold the roof set up and a basic beginning made to the roof, and strawbales brought for many uses.

Tarps were used for shelter from rain and for bases on which to mix cob. Mostly we mixed the sand, clay, water and straw by doing the cob dance - mixing with our feet.

We would build with cob on the stone foundation.

Em helping

It was work that can make you very dirty. Em was very involved in mixing the cob with her feet and then adding it to the wall before the children were diverted to a structure of their own - a bench a little distance from the clinic.

clinic on Aug 13

This was the progress made to Aug 13.

A welcoming, leading wall was added so we could practice different features such as nooks, arches, shelves, benches. Here it can be seen with straw left on top to keep the cob from drying too quickly. A level for keeping the walls straight can be seen and if the walls were not straight, they were shaved with saws or machetes. The walls were 10 - 12 inches thick and an insulating layer of strawbale would be tied to the outside later.

tarp over eating/lesson area

So much more than simply building was taught. How do you set up the building area? A place for eating and storage for tools was set up under a tree in which a tarp was hung for shelter from the rain. We also had some formal "textbook" lessons here.

shape of the roof

The roof had a very intriguing shape.

The clay pond can also be seen here. This pond was made from a tarp draped over an outline of strawbales. It was filled with water and lumps of clay were dumped into it to be squished by someone's stomping. When it was an even consistency, gobs of it were carted in buckets to the mixing sites (smaller tarps) where teams of two would mix it with the other cob ingredients.

The tarp covering the wall has a bulge in it. That day we were taught how to insert a window with a frame and that's the frame sticking up beneath the tarp.

Wall with various features

Here you see some of the features we practiced. Little nooks, arches, a shelf and a bench seat with a rock back.

In the background you can see an area spread with tarps where cob was mixed. After mixing and forming into cobs, it might be dragged to the wall or transported by wheelbarrow. Sometimes a cob-toss was formed and the cobs were passed down a human chain. The girls were part of a cob-toss the first day we were there and they enjoyed it.


Other interesting things could be found around the site. Here is a vise, used to hold lumber while it was cut.

Curving walls were built on three sides while the front was left for large windows. One of the beauties of cob is that it can easily be sculpted into any shape. It lends itself to so much creativity and square walls are not necessary.

Every evening there were discussions or further lessons. One session I particularly enjoyed was of slides shown of cob buildings around the world. Some in Yemen are 13 stories high and have stood for centuries. Some cob houses in England have been continuously occupied for over 500 years.

rocks used in building, too

Rocks can be added to the walls. They will help the walls go up faster and they have high thermal mass, too. Here is a row waiting for cob to be placed around them. You can see holes poked in the walls. These were to help with drying and were made with sticks called 'cobbers thumbs'.

We learned methods of attaching window and door frames to cob. You can see a doorframe here on the left. If they don't need to open, glass windows can be put in in wild shapes, totally open to creativity.

Linda and the wall

Linda, one of our teachers, is standing inside the clinic. It's now Aug 14 and the walls are getting higher.

When the walls got too high to work on, we stood on strawbales. Those bales were very versatile.There was one difficulty with these bales, though. They had too much hay in them. If "pure" straw can be used in the bales, they will last much longer.

Here you can see string hanging from some of the holes. These were to mark holes that went all the way through the wall. They were made so the strawbales could be attached to the walls later.


Here are strawbales being added to the outside of the wall. They will be tied onto the wall with string, using the holes that have been left for this purpose. Then a layer of cob will be added to the outside of the wall for the final finish.

floor layers

The second week of the course was intended to give us finishing touches and here you see an earthen floor being laid. A modified cob mixture was tamped over leveled stones and then a finer mixture of cob was laid. You can see part of a home-made tamper at top centre.

underground fire stove

Ianto was brimming with knowledge about all aspects of building and living with cob.

Here he is with a simple, very hot-burning stove he constructed in just a few minutes. The fire is underground. Wood fuel is inserted down a sloping hole (see left) and the fire burns at the bottom of a chimney, the top of which also serves as the stove. (There is very little smoke from a fire like this.) A pan of water set on stones is soon boiling for tea.

plastering the walls

Lessons in how to make a very fine mixture of cob for plaster were given on the last day.

This is Aug 18. The course is complete. I feel overwhelmed with new knowledge and exciting possibilities.

our tent

The course participants slept in tents. We moved ours three times, trying to find a flat base. The first two nights we rolled into each other but the picture shows where we finally stayed. I wondered how my girls would manage with camping and the lack of modern facilities, and was surprised at how well they adjusted to a different style of life.


They didn't like the outhouse but they ran around barefoot, swam in a pond with "yuck" at the bottom, slept soundly at night and generally enjoyed themselves.

The picture shows the ponds which the doctor hoped to use for hydro therapy.

Kitchen/dining room

We ate in a large barn which you can see in the background (at right) through the doorway from the kitchen. This end of the barn was set up for dishwasing and making very simple meals. Our main meals were made in the doctor's house and brought to the barn when ready.

Only vegetarian meals were served but they were delicious.

My girls enjoyed meeting the other participants and Dee, in particular, had many great conversations learning all she wanted to know about everyone. She was my main helper if I forgot someone's name or didn't remember what they wanted to do with their new knowledge about building with cob.


I'd been told that children could participate but that part of the experience was disappointing. Children were not tolerated well and were soon set to work on a cob bench a little distance from the main building and parents were expected to work with them.

Most participants were there for one week but those of us who stayed for the second week hired a babysitter to look after the children that week. That worked out better because it meant we could be full participants and the babysitter showed the children a very good time.

path through woods

There was another disappointing aspect for me. The workshop was billed as a "healing experience". We were, after all, building, with natural products, a clinic for healing. However, there was friction between some of the leaders which was sad to see and which hindered healing for me.

But I did find the natural beauty of the setting to be healing. I savoured the walk from our eating barn to the worksite. The path ran through a quiet woods.

ripples barn shadows
Then there was the night sky with it's stars, the shadows in the barn cast by the early morning sun, and the water at the beach where we took the children on the weekend.

Someday I still hope to build a small, cozy cottage of cob and strawbale and on this course I learned much to help me when I get to that dream. There are books that can do a better job of the details than I can but I hope I tweaked your interest in alternative buildings, especially cob.

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Copyright© 2002 by Martha Greenhow
Etobicoke, Ontario, Canada