CobWhat is it? Modern cob is made of clay, aggregate, straw, and water. Cob differs from adobe in that it is built “wet“. Mixed together in small batches, formed into shape with the hands and then placed on the wall while still wet, cob allows a builder to easily create custom shapes.
Cob also differs from adobe in that it can work very well in cool, damp areas; these are the areas where cob originated. Like other thermal mass materials, cob is fire-resistant, durable, unappetizing to insect and vermin, and an excellent thermal storage device.
How does it work? Cob works on the principle of thermal mass. If you've stood next to a big rock on a summer evening, you'll understand what thermal mass is. That rock absorbed heat all through the day, and releases it all night. By using the roof to shade a cob house during the summer, we can create the opposite effect, something you no doubt have felt if you've ever sat on a rock in the shade of trees on a hot summer day.
What are the benefits? Probably the best material for an inexperienced owner-builder interested in saving on material costs, building with cob is usually reserved for those who have time on their hands, the right location, and the willingness to design as they build.
Cob allows people who normally couldn’t or wouldn’t build their own house to be intimately involved in every decision associated with building. Because of the “wet” building technique, cob houses are characterized by curves and not edges; wavy, organic walls instead of ruler straight ones. Cob structures are best built small, which translates to lower heating and cooling costs.
When does Exup use cob? An excellent choice for post-disaster areas in less-developed nations, where labor and materials are available, but financing must be used sparingly and with real effect, Exup can use cob's natural benefits as thermal mass to tie in with low and high-tech solutions, ranging from solar hot water to ground source heat pumps.
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