Alternative home structures: The cob home

Discussion in 'Architecture & Engineering' started by Mrs.Lucysnow, Jul 22, 2009.

Thread Status:
Not open for further replies.
  1. Mrs.Lucysnow Valued Senior Member

    Who here knows anything about Cob homes? From what I understand its a mixture of sand, earth and straw mixed together into lumps and molded into a dwelling.

    From what I understand you can practically create anything from cob but you cannot build too high? Why not?

    I have property in Belize and have been seriously thinking of using cob to build not only a home but some cottages (If its too complex then maybe only the cottages)

    What is the best climate for a cob dwelling? Is cob convenient in humid climates? I understand that it must be kept very dry during the building process but once it has hardened will it mold in humidity over time? Does it regulate temperature so it remains cool in the summer and warm in cooler climates?

    How practical is this really? I have heard that building from cob is really labor intensive as it takes an entire team because the molds must be built by hand. Are there actual cob builders left? I was thinking of taking a cob workshop but to tell you the truth I am not interested in building an entire structure myself though I have an interest in the process. I have heard that it is much cheaper to build with cob. As far as planning is it really necessary to know where every outlet will be in a plan? Which means finding an architect who knows a lot about this process. I have heard that you have to think in advance were all electrical lines will run as it has to be built in before its hardened otherwise you cannot be accommodated.
    Last edited: Jul 22, 2009
  2. Google AdSense Guest Advertisement

    to hide all adverts.
  3. scorpius a realist Valued Senior Member

  4. Google AdSense Guest Advertisement

    to hide all adverts.
  5. svenglezz Registered Member


    I have a web site (refer to my profile for link)

    If you go to my Internet Links then to Architectural, on this page you will find links to Green Building type of structures etc. and more.

    Hope it helps and if you find anything that I don't list send me the link and I'd be happy to add,
  6. Google AdSense Guest Advertisement

    to hide all adverts.
  7. Mrs.Lucysnow Valued Senior Member

    Thanks Sven. Where is the link?
  8. Meursalt Comatose Registered Senior Member

    Do they have any capability for rammed earth over there?

    I've always wanted to build that way. As far as I know it's an Australian thing though,not as common overseas. And... it can be expensive to build (but the long run savings will offset that).
  9. Mrs.Lucysnow Valued Senior Member

    It can be found all over the world but Cob is english. There are some cob homes in the States but very few. The cost is because of the need of lots of labor isn't it? Because the soil is already provided by the property given that its the right type and the straw etc doesn't cost so much. In Belize the labor is cheap so it shouldn't be so expensive. Sven sent me his resources site:
  10. Watcher Just another old creaker Registered Senior Member

    Lucy, the structural integrity of a cob home is extremely poor during an earthquake. Unless you live in an area where the chance of an earthquake is virtually nil, I would never consider this type of dwelling. Unfortunately Belize is prone to earthquakes, as you must know. The Swan Island Transform fault is just offshore, and caused a 7.1 magnitude quake back in May 2009.

    You will find that the proponents of cob homes say they are "more earthquake resistant" than adobe, but what they DON'T mention is that either adobe or cob is 10X (or more) more prone to earthquake damage than a properly designed structure of wood, steel or reinforced concrete.

    There is no way I would live in a cob home in that area, no matter how well-designed, it is far too weak and subject to instant collapse in even a minor earthquake.
    Last edited: Nov 1, 2009
  11. Thoreau Valued Senior Member

    I just saw a TV show on this the other day. It really is quite amazing the community they've developed. Completely self-reliant and self-sufficient. I've honestly considered joining them.
  12. mugaliens Registered Member

    I know very little, except that you left out the clay, that ground shale can be added to reduce shrinkage, and a stucco or river rock outer layer will protect the cob layer from erosion.

    But these folks know quite a bit!

    It fractures easily under compression, and is the principle reason why walls are usually around a meter thick.

    It's essentially a mud hut. With proper roofing, and exterior layer (like stucco), and a controlled inside climate, mold shouldn't be a problem.

    It works off the principle of thermal mass, a technique used primarily overseas, and very rarely in the US.

    Just as with any other house, if you want electrical, plumbing, light, ventilation, access, and any of the myriad of other features built into homes, you're going to have to plan for it!
  13. Mrs.Lucysnow Valued Senior Member

    Thank you Mugaliens for all the explanations and the cobworks link!! The information is very timely.
  14. faces Registered Member

    I will be building a cob house in belize as well, as for drying out, cob houses in the UK dry and you couldn't go to a damper place, still standing after 500. Some info regarding earthquakes I have seen research to say they are stable.
  15. Mrs.Lucysnow Valued Senior Member

    Where is your property? Mine is in Mt. Pine Ridge Cayo district and its not really that damp at all up in the mountains.
  16. Baron Max Registered Senior Member

    Lucy, if you're really planning to build something like a cob house, please do a lot of research about it. It's not all that it's cracked up to be and, from what I've heard and read about them, they aren't building code-compliant so they might not even be permitted in your area. And, not being code-compliant might mean a lot more "bad things" going on.

    Another thing, please look at other systems for building that are apparently far more energy efficient and are built according to codes against earthquakes, storms, etc.

    Please check things out thoroughly before you leap.

    Baron Max
  17. cosmictraveler Be kind to yourself always. Valued Senior Member

    I'd think I'd rather have something easily transportable, in case I must move, lightweight and easy to make.

    Please Register or Log in to view the hidden image!

  18. faces Registered Member

    Not to far from you, 1 mile off the western highway between san ignacio and belmopan.
  19. Rick Roamer Registered Member

    True you should do research, but I'd like to know what the negatives are against building with cob. The reason that it is not to code is b/c in the US most people, including government officials and those in the housing industry do not know much about cob. They've been taught how to build with industrial materials and not natural materials.

    To me the positives are overwhelming. For one you are using natural building materials so you are not contributing to the pollution and environmental degradation that the housing industry creates. Also not just for the health of the planet but your own health. Many industrial materials are hazardous to work with and hazardous to dwell in, for those with sensitivities. I've never heard of an allergy to clay...its a very clean living environment that is resistant to bugs, termites, and mold. It's also very affordable, can usually be built with materials from the land that you purchase (if there is clay). And it can last for centuries, which can't be said for many houses built these days.

    Another thing is that you can design your house to whatever shapes you like. You aren't confined to rectilinear shapes, which is more prone to wear down b/c it is an unnatural shape in nature. It's very aesthetically pleasing, the interiors of cob. Just google some pictures and you will see. The exteriors sometimes are funky, but we need more of that compared to drab monotonous fabricated houses.

    I will have to do more research about earthquakes, but as far as I know the main concern with building cob is not to build in a flood plain, because if the house is immersed in water then you will have problems. But seeing as cob has been used for hundreds of years in wet climates like England, it holds up very well to moisture, as long as you have a proper roof and drainage so that water doesn't build up around the foundation.

    Oh and did I forget to mention the most incredible quality...its completely fireproof!

    Its true that it does take longer to build...well sort of. All houses take a long time to build, but you usually just pay someone else to do it. With cob you are encouraged to slow down you life, contemplate what you are doing, how you are doing it. You learn to become in tune with the land and are encouraged to build with the cycles of your specific land and the angles of the sun(to maximize energy efficiency). It actually takes a similar amount of time to a normal house, just depending on how much help you have. But the thing is, cob is such an interesting form of housing, that you can attract many people to volunteer with you.

    If anyone knows any negatives to cob please share with us. It is true that if your area doesn't have cob codes than there will be an uphill battle (you may not want to build a house that could potentially be torn down). BUT, from what I have heard is that you can work with the city in many cases, it just takes respect for them and initiative.

    I hope this sheds light on a beautiful technology for you.

    -Rick Roamer
  20. Kernl Sandrs Registered Senior Member

Thread Status:
Not open for further replies.

Share This Page