Cobbing a Woodstove?

Discussion in 'Designing, building, making and powering your life' started by Pakanohida, Oct 26, 2011.

  1. Pakanohida

    Pakanohida Junior Member

    Joined:
    Feb 27, 2011
    Messages:
    2,984
    Likes Received:
    20
    Trophy Points:
    38
    So, there is the question. I have a woodstove, I want to insulate it with cob, maybe even make an area to bake with it.

    Aside from possibly having to re-enforce the floor, does anyone know if this is a good / safe idea? Thoughts in general?
     
  2. Michaelangelica

    Michaelangelica Junior Member

    Joined:
    May 2, 2006
    Messages:
    4,771
    Likes Received:
    8
    Trophy Points:
    0
    What's cob?
     
  3. Pakanohida

    Pakanohida Junior Member

    Joined:
    Feb 27, 2011
    Messages:
    2,984
    Likes Received:
    20
    Trophy Points:
    38
  4. permasculptor

    permasculptor Junior Member

    Joined:
    Jul 10, 2007
    Messages:
    727
    Likes Received:
    1
    Trophy Points:
    18
    I have seen ovens built out of cob so it should be ideal for insulating I intend on using it for the same when I get around to building my you beaut solar pre heated rocket powered cooktop/oven/water heater/ steam generator.
     
  5. eco4560

    eco4560 New Member

    Joined:
    Feb 9, 2009
    Messages:
    5,925
    Likes Received:
    8
    Trophy Points:
    0
    Let me know when you do - I'll come and stomp in the mud with you.
     
  6. annette

    annette Junior Member

    Joined:
    Jul 8, 2010
    Messages:
    889
    Likes Received:
    0
    Trophy Points:
    16
    Oh me too permasculptor, I'll help and learn at the same time if you want a hand. Let me know!
     
  7. permasculptor

    permasculptor Junior Member

    Joined:
    Jul 10, 2007
    Messages:
    727
    Likes Received:
    1
    Trophy Points:
    18
    Will do you two.
     
  8. Pakanohida

    Pakanohida Junior Member

    Joined:
    Feb 27, 2011
    Messages:
    2,984
    Likes Received:
    20
    Trophy Points:
    38
    That one is outside in the "outdoor kitchen" area. Double chamber bread / pizza oven, a few rocket cook tops, grill, and smoker for wild game, etc. Hmmm, water heater... do I have room.
     
  9. Don Hansford

    Don Hansford Junior Member

    Joined:
    Dec 17, 2009
    Messages:
    115
    Likes Received:
    0
    Trophy Points:
    0
    There are two types of cob ovens I'm aware of. One uses a brick or earthen floor as a heat sink, and has a thermally insulated roof. The fire is removed when the cooking commences, utilising the residual heat trapped in the structure. The other type is less insulated, and has the fire burning whilst cooking.
    While you could use the wood stove inside a cob "blanket" I don't know if it would really be any more efficient than a "pure" cob oven.
    Interesting idea, though - let us know the results if you do go ahead with it.
     
  10. Don Hansford

    Don Hansford Junior Member

    Joined:
    Dec 17, 2009
    Messages:
    115
    Likes Received:
    0
    Trophy Points:
    0
    Add me to the list, too permasculptor - have shovel, will travel :D
     
  11. Spidermonkey

    Spidermonkey Junior Member

    Joined:
    Jul 25, 2011
    Messages:
    121
    Likes Received:
    2
    Trophy Points:
    18
    It looks amazing, I've never heard of it! Is anyone in Australia teaching this? Would it be suitable for a subtropical climate?
     
  12. permasculptor

    permasculptor Junior Member

    Joined:
    Jul 10, 2007
    Messages:
    727
    Likes Received:
    1
    Trophy Points:
    18
    Will do Don but Ill have to pull my finger out and get it designed and built rather than dreamt of first.I am planing this for a semi outdoor area that is currently an open walled shed on the north side of my house which I am planing to merge to zone 1 so am compiling elements .Once the plan is complete I intend to use cob to make the permanent structures. It is also an avenue I intend following for sculpture production. I am focused on sustainability and it don't get much better than cob. it is a brilliant building material as it is strong enough to build free form without reinforcing in many applications . There have been courses in the past on the sunshine coast for Pizza ovens run by Bob Cameron from Rockcote and building courses have been run in the past by Alan Atkins from Permaculture Noosa. I have no reason to think it would lack suitability to a subtropical climate as the rendering is re done when required,I heard a rumour that cow dung in the render sets up a funky living surface that lasts best ,need to research all this to a greater extent but I think i'm on the right track.would be great to have you all around. I might have to call this development the beer hall!
     
  13. Don Hansford

    Don Hansford Junior Member

    Joined:
    Dec 17, 2009
    Messages:
    115
    Likes Received:
    0
    Trophy Points:
    0
    Earth building of any type (Cob, adobe, earthbag, etc), are all suited to practically any climate zone, given a few provisos are met.

    On the Earthbag building course I attended, the prime saying was "you need good boots, and a good hat". In other words - solid foundations, and a roof and/or "skin" that will keep the weather from eroding the outer surface.

    Remember all those pictures of the Mediterranean holiday places, with the sparkling white houses? A fresh coat of lime-wash every couple of years gives that look, as well as a finish that (if done correctly) is virtually the same as the limestone the wash was made from, and will stand up to quite severe weather. Patching up after a storm is quite quick and easy, too.

    Most structures (apart from earthdomes) should have a roof with eaves that extend far enough out to protect the walls from the majority of driven rain.

    Remember, more than two-thirds of the worlds' population live in homes made either entirely, or mostly, of earth. It has excellent heat-flow management (not to be confused with insulation) properties, and there are some earth buildings that have been lived in continuously for many hundreds of years.
     
  14. Michaelangelica

    Michaelangelica Junior Member

    Joined:
    May 2, 2006
    Messages:
    4,771
    Likes Received:
    8
    Trophy Points:
    0
    Thanks, so how is 'cob' different from Adobe bricks and Rammed earth?

    Wouldn't you get cracks in a mud oven/insulator when heated?
     
  15. Pakanohida

    Pakanohida Junior Member

    Joined:
    Feb 27, 2011
    Messages:
    2,984
    Likes Received:
    20
    Trophy Points:
    38
    Adobe bricks are the same as cob except left out to dry as a brick.

    Normal bricks are cob, heated and formed.

    Rammed earth uses wooden forms, then earth is tossed into the form, and a person must tamp either by human or mechanical means.

    Cob itself is simply mud, straw, sand. Think of straw as rebar, sand as concrete, and the mud binds it all together. You simply patch any cracks with earthen plaster.

    Cob homes are more insulated then any kind of "stick" construction, and lasts centuries longer. Average cob homes are still around from the 1500's & earlier in Europe. The link to cob cottage I provided elsewhere in this thread, well, the owner visits NZ & Australia sometimes as he is writing his new book on the subject.

    It is useable in humid climates (like mine) and like Cob Cottage, you just need to build the roof properly to protect the walls. If any of you ever come out here to see Cob Cottage, I gotta tell ya, its worth the trip to see!
     
  16. Michaelangelica

    Michaelangelica Junior Member

    Joined:
    May 2, 2006
    Messages:
    4,771
    Likes Received:
    8
    Trophy Points:
    0
    I have built in adobe; I guess I used cob to patch it and to help form curved walls?
    It still intrigues me how you build with cob
     
  17. Don Hansford

    Don Hansford Junior Member

    Joined:
    Dec 17, 2009
    Messages:
    115
    Likes Received:
    0
    Trophy Points:
    0
    The usual way is that you mix your mud and add the straw, the people mixing form the clay/straw mix into "cobs" - a large handful - and, toss it from hand to hand a couple of times so that it stays together in a single lump. This is thrown to you (as the "cobber") then you 'slap' the cobs on top of your foundations (traditionally a course of stonework about 60-100cm high). This will go on around the wall until you reach a certain height (depending on the stiffness and moisture content of your cobs, but usually about 60cm). Then you must wait a day or so for that to stiffen up, before you build more on top. Once the wall/structure is finished, you then use a "cob-knife" to trim the 'hairy' bits of straw off, and get close to the final shape you want. A coat of mud plaster then finishes of the outside and inside walls.
    Cob building is considered by some to be the ultimate team-building exercise, and there is even some conjecture that many of our current team ball sports, originated from cobbers letting of steam after a long day - but that's another lesson :)
     
  18. Pakanohida

    Pakanohida Junior Member

    Joined:
    Feb 27, 2011
    Messages:
    2,984
    Likes Received:
    20
    Trophy Points:
    38
    I honestly just find it fun to do too! From stomping to putting it on a wall myself (yes I cob by myself)... it's just fun cardio! :D
     
  19. Michaelangelica

    Michaelangelica Junior Member

    Joined:
    May 2, 2006
    Messages:
    4,771
    Likes Received:
    8
    Trophy Points:
    0
    Straw and/or cow manure are needed in adobe too; But cob sounds easier than man handling huge mud bricks up scaffolding a few metres high!
     
  20. Don Hansford

    Don Hansford Junior Member

    Joined:
    Dec 17, 2009
    Messages:
    115
    Likes Received:
    0
    Trophy Points:
    0
    That is one of the advantages cob has - you can make the cobs to suit the strength of the building team, i.e. women and kids can be just as involved in the building as the men.
     

Share This Page

-->