Cob
No house can be considered more warm and cozy than that built of Cob, especially when thatched. It is warm in winter and cool in summer, and I have known workers to bitterly bewail their fate in being transferred from an old 15th or 16th century Cob cottage to a newly built edifice of the most approved style, as they said it was like going out of warm life into a cold grave.
From “Book of the West” by S. Baring-Gould
What is Cob?
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Cob is a form of traditional earthbuilding that uses a mix of decomposed shale, chopped straw, clay and water to build durable walls that moderate a building’s interior temperatures.
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Cob was once the cottage material of choice in Devonshire, South Wales and the west of England.
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Many Devon Cob houses are 200 to 300 years old with some dating to the 1500’s, with walls four feet thick. The composition of the Cob varies with local conditions.
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Cob is turned on the ground with a tractor. It goes up in “perches”. Each perch is roughly 16 1/2 feet long and 12” high. Perches are created by laying loaf-sized “cobs” onto the wall in a diagonal pattern whih are then “thumbed in”.
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After curing, the walls are smoothed with lime and/or clay plasters. (Adapted from “The Earthbuilder´s Encyclopedia” by Joe Tibbets).
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Sheltercraft is currently developing a cob module that can be quickly assembled into panels on-site. In the meantime, we still use semi-traditional methods to build cob walls.