What is Cob…..or is it Cobb??          

Cob or Cobb (you can spell it both ways) is a form of building with mud, clay and straw. In fact building with mud was common in traditional societies all over the world. The ratios and mixes differed and gave rise to different building methodologies like adobe, cob, bale-cob, strawbale etc. The local weather conditions and availability of materials are the primary driving factors for choosing one method over the other. The building style is very flexible and even allows for the use of a mix of styles within one house and this is exactly what we plan on doing.  We will be using straw-bale for the outer walls and pure cob for the inner walls and other accessory structures like an outdoor cookout area and privacy/garden walls.  Cob is a poor insulator. It works as a heat battery and is best used in places without extreme winters;  where the daily temperature variation is more extreme. The thermal mass (or thermal battery) of cob helps to absorb the warmth during the day and release it at night or vice-versa. Straw on the other hand has excellent insulation; but is a poor thermal battery. Hence it is best used in places that have extreme winters; especially in places where both the days and nights are either warm or cold. Of course, all this talk is only referring to the walls of the house. These houses still need foundations, plumbing, wiring and roofing like conventional houses. However, on the whole, they tend to be extremely low impact on the environment – cob; more so than straw. They also lend themselves easily to organic shapes and can be built by anyone who is fairly handy and willing to put in the effort.  Errors during construction can be easily corrected. Cob is pest/termite resistant and fire resistant. A properly plastered straw-bale house also has the same characteristics.  Both cob and staw-bale houses should be plastered using earth based plasters since they need to be able to breathe. Lime based plasters are extremely water resistant and when rendered correctly provide a durable, beautiful and non-toxic finish. There are entire books, videos and workshops devoted to this topic.  I hope this has triggered your interest enough to snoop around the internet for further information. If you still need convincing (not that I am trying to proselytize), just check out photos of cob houses on Pinterest.

We decided to start small and built a Cob Oven in our backyard. We haven’t plastered it yet and will update the photos below once we have finished it. In fact, if you want to try your hand at cobbing, we would highly recommend that you start with a cob oven. There are plenty of online resources and YouTube videos of people building cob ovens. Don’t get too caught up with the technicalities of the right mix or the look of the oven. Just start building and you will gain a lot of experience as you build. And if it all goes wrong, you can simply take it down, add water, remix the cob and reuse the material to build again!