Mud building/ cob houses

Discussion in 'Designing, building, making and powering your life' started by Erika, Apr 3, 2011.

  1. Erika

    Erika Junior Member

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    Hi,

    I've just watched "first earth" which I found at PRi's homepage. I'm now looking for people who could help me with some advice on mud building.

    I intended to build a wooden play house for my children this summer, but I've considered building with ferro cement (which i don't like because of the energy). I had put the mud building aside, because I haven't found any good information. But now I'm lost, I have to build a mud play house! I want to start now! But the snow is not yet gone! So I have time to plan.

    I would need information on:

    1. The ground moves a little during winter when it freezes, about 5 cms perhaps. What do I need to do to prevent the cottage from being damaged because of that?

    2. The words mud, soil and earth are used in videos I've seen. On my ground I've sandy soil with gravel. I plan to dig out a damm in the future. Can I use sandy soil? What do I need to complement it with?

    3. What can I mix in? Any kind of staw? Bark? Little twigs? It has to be dried, right?

    4. Do I need to keep the walls wet while building? I will not finish it in one day!

    5. I thought to do the roof in the same material. Could I use "chicken-net" to form it as i please and then cover it in mud? Or does it have to be covered with another roof material (straw?).


    I'm so much looking forward to this!!!
    I'll try to learn how to post photos here, so I can show the progress.

    Best regards
    Erika
     
  2. Mudman

    Mudman Junior Member

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    Erika,
    All the best with your project, sounds like you are building with cob
    Do a search for cob houses and you might find some more information.
    I would recomend putting on a solid roof or maybe an earth roof.
    I just did a google image search and came up with this place https://small-scale.net/yearofmud/
    Cheers
    Kurt
     

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  3. Erika

    Erika Junior Member

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    Thanks Kurt,
    I'll check your link out.
    I've watched videos, but they tend to be about the cheerful process of building, and don't give step by step instructions. But it's still very inspiering to see what's possible to create.

    If anyone else need info like this or if you have good info or links, please post :)
    It's rather timeconsuming sometimes to find good pages.

    Regards from Erika
     
  4. sweetpea

    sweetpea Junior Member

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    Aren't those cob houses the cutest things? They are very tempting to try. There's a lot of rammed earth housing happening in California. It makes very beautiful walls. You might want to look into it. Here's a site that has links and info:

    https://www.diyrammedearth.com/

    It's all done with clay soil, there's no getting around it, unless you want to add cement or concrete (not the posthole stuff) to your sand. there are lots of fascinating cement buildings, too. Great for insulation, fire protection.

    And as you say, the heaving of soil is very serious, and the same engineering requirements are necessary for any type of housing. Foundations need to be below the frost line. So getting the engineering right is probably the most important thing. The village of cob houses are in Northern California where the soil doesn't freeze, and summers are dry, so it's probably an easier environment. The Spanish missionaries 200 years ago made missions from the clay in California. Some are still standing, but take a lot of maintenance. Again, no summer rain, so the bricks dry out in the summer. Let us know what you try :)
     
  5. Pakanohida

    Pakanohida Junior Member

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    https://www.cobcottage.com/

    The above link is the working place for Ianto Evans, the man knows Cob and travels world wide teaching and learning about it. NZ Parliament building is made of cob! My (work in progress) outdoor kitchen is made of cob!

    1. The ground moves a little during winter when it freezes, about 5 cms perhaps. What do I need to do to prevent the cottage from being damaged because of that?

    A good foundation is what you will cheerfully need!

    2. The words mud, soil and earth are used in videos I've seen. On my ground I've sandy soil with gravel. I plan to dig out a damm in the future. Can I use sandy soil? What do I need to complement it with?

    You will need to test your soil, make test bricks, and you will most likely need to add clay and straw.

    3. What can I mix in? Any kind of staw? Bark? Little twigs? It has to be dried, right?

    Weed free straw. Bottles, cans, Time capsules of hemp seeds for the future.

    4. Do I need to keep the walls wet while building? I will not finish it in one day!


    Yes, it needs to dry slowly, I suggest reading Ianto's book.

    5. I thought to do the roof in the same material. Could I use "chicken-net" to form it as i please and then cover it in mud? Or does it have to be covered with another roof material (straw?).

    I know you can with hemp cloth and straw.. not sure about the lightweight cement approach, I would suggest emailing Cob Cottage direct.
     
  6. Pakanohida

    Pakanohida Junior Member

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    @Sweetpea

    Up I-5, go onto 42S towards the town of Coos Bay and stop in "Coquille" after getting permission to visit Cob Cottage...

    They are in temperate rainforest building a new Cob village. The place, for lack of better words is breath taking and inspiring.
     
  7. sweetpea

    sweetpea Junior Member

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    Erika, while a mud roof might look cute, it's got to be engineered right. We just had a horrifying downpour for 3 days, and I've got conventional buildings, and things were leaking where they've never leaked before. You can't do anything at that point to try to save things if they aren't put together right. Or if there is a snow load, it's way better to make a rustic wooden roof with eaves that protect those walls. It's very, very dangerous to have such a structure just made out of chicken wire and mud, because there's very little structural integrity there. You might also look at how they made the California Missions, they all have wooden roofs. The standard homemade clay/straw bricks must be in the sun, no rain or dew on them, turned regularly for 30 days before using.

    Pakanohida, yes, I saw all the You Tube pieces on those cob houses, and it's inspiring, although I am trying to have less and less maintenance, and I'm afraid those darling little things need maintenance more than one might realize. :)
     
  8. Mudman

    Mudman Junior Member

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    Erika,
    Another option you could pursue is to build it out of strawbales.
    You could get the walls up in a day and then have fun putting a clay render on with your kids.
    Do a google search for strawbale in Sweden and there are a fair few over there.
    Looks the same as cob but alot quicker to construct. Would give you very good insulation as well.
    But definately put a proper roof on with wide overhangs.

    Cheers
    Kurt
     

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  9. Erika

    Erika Junior Member

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    Dear friends, thank you for all your replies! I've known of permaculture for a little more than two years and have don a PDC but it wasn't until recently I discovered this page. It's so good to have an ocean of people willing to share and support. Permaculture in Sweden is still small (as is Sweden!). Anyway...

    Hm, I thought of straw-bale technique as more timeconsuming than cob, but I may well be wrong. And I got really eager to shape this little playhouse just as I wanted, and cob is so good for that. Possible with strawbale too, but not as easy...
    Thanks for all roof-safety-warnings! I saw this fero-cement technique, and it's supposed to be very strong. So my reflection was that perhaps it was possible to replace the cement with cob. I've taken your warnings and will make a proper wooden one.
    And a proper foundation. Since I was just planning a little playhouse I thought I might not have needed this. I want to build it just under a big birch, and there's a loot of roots in the ground. But, ok, I'll stick to the rules :) and figure something out!

    So, for the time being, with this project being larger than I first thought, I guess I ought tobe greatful that I was just given a big pile og salix from a garden nearby. It's way much easier to build a "hut" from that. Only a few hours. It'll do, until I have more time.
    https://www.google.se/images?hl=sv&...=UTF-8&source=og&sa=N&tab=wi&biw=1899&bih=841

    Please take care, and thank you again.
    Erika
     
  10. pebble

    pebble Junior Member

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    " NZ Parliament building is made of cob! "

    Which building are you talking about? AFAIK none of the current parliament buildings are cob/earth buildings.
     
  11. Pakanohida

    Pakanohida Junior Member

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    It's certainly less maintenance then a stick constructed home, far less. I don't relish the idea of 30 year renewal of a wood stick construction methods when my mortgage is up in nearly the same amount of time. I am trying to do all my buildings on the property to last more then my life time.
     
  12. Pakanohida

    Pakanohida Junior Member

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    I am unsure, I was told this by Ianto Evans when I met him last year. He had just returned from NZ & working on his next book regarding cob and he was telling us how annoyed he was he has to go back because on the very last day he learned that the buildings were cob built with earthern plaster over it. I will need to get back to you on this & research it for you.

    Here is a small bio of Ianto Evans, for an fyi.

     
  13. pebble

    pebble Junior Member

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    Thanks :) I know of Ianto Evans and his work, and think The Hand-Sculpted House is a beautiful, essential work.

    I wonder if he is talking about some of the original buildings from the 1800s? Here's the current parliament buildings. Two are obviously modern, mainstream buildings. The other two don't look like cob/earth to me.

    https://www.parliament.nz/en-NZ/AboutParl/HstBldgs/Buildings/

    There are some older earth buildings here (from the 1800s), notably Pompallier House (rammed earth)

    https://www.nzine.co.nz/images/articles/082PompellierHouseRussell.jpg

    https://en.wikipedia.org/wiki/Pompallier_House#Construction

    I'd be very interested to hear what you find out.

    There's also lots of cob cottages from that time too, miner's cottages etc.
     
  14. Pakanohida

    Pakanohida Junior Member

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    I'll let you know, but it will take some time. He's literally on the other side of town, and I never see him, or the people at Mountain Homestead either, we all are doing our own things. They have both been in this town a long time, I am still setting up and learning all I can.

    On the flip side, I am building a dual chamber cob oven (mark 2) in the next few months. I'll make a new post for that.
     
  15. sweetpea

    sweetpea Junior Member

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    Pakanohida, are you thinking that wood construction homes only last 30 years? The majority of houses in the US were built between 1940 and 1980 (that's 30 years ago!! eeeeeek!) and are fine, as elsewhere. Not sure what you mean. Stick houses built in the late 1800s are still going strong.

    The majority of missions built from clay are not, however. You can walk around the outside and see how the clay crumbles. there will always be cracks in plaster or clay as the foundation shifts. Especially a new foundation that takes a few years to settle, there's a constant maintenance of hairline cracks, especially around windows. Salt air also affects clay-type bricks causing them to crumble. They used to make boats out of cement during WW2, and the salt water breaks down the cement. There's a State park at a beach near me where the Cement Boat, as everyone calls it, is slowing disintegrating as it sits on the beach.

    https://www.missionsofcalifornia.org/
     

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