Q. We're looking to move to the country. Several of the property details I have been sent mention "cob" construction. What is this?

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A. Cob is basically a variation of the ancient method of building with mud and straw that has been used throughout the world for thousands of years. In the UK, this type of construction was used in several parts of the country including Hampshire, Wales, Dorset and Cornwall, but was particularly popular in Devon.
Traditionally, English cob was made by mixing clay-based subsoil with straw and water, which was then built up in layers (normally on a stone foundation), with each layer being given time to dry out first. Finally, the walls would be rendered with a mix of quicklime putty and coarse sand, followed by a lime wash. Unlike most modern coatings such as cement render, gypsum plaster and vinyl paints, this traditional finish is breathable, allowing any moisture to evaporate quickly - a fairly important consideration when your house is basically made out of mud.
But if all this all sounds like stepping back into some historical time-warp, don’t worry. Thousands of cob houses still survive today. Yes, many of them may date back hundreds of years, but living in them is really no different from most other types of older rural property.
What’s particularly interesting about cob, however, is the fact that it is currently undergoing something of a renaissance. The traditional skills, almost lost in the second half of the 20th century, are being revived, and there are specialist suppliers and builders to handle any necessary repairs or renovation work.
Perhaps even more remarkable is the fact that growing numbers of brand new and often strikingly-designed cob homes are now being built. Why? Well, for one thing, architects are increasingly being drawn to cob construction because, being basically moulded out of gloop, it lends itself to exciting new flowing shapes. More important in today’s world, it is very environmentally friendly. Cob homes are cool in summer and warm in winter. The construction process consumes virtually no energy and produces no pollution. Finally, the raw material of cob is not only infinitely recyclable, but can generally be excavated from the building site itself, thereby reducing transportation.
In fact, I suspect we may all be hearing rather more about cob-built housing in years to come.