Mud Huts

Thread Starter

thingmaker3

Joined May 16, 2005
5,084
My wife and I just spent some time in a temperate rain-forest learning to build cob housing. The workshop was quite enjoyable, not only for skills learned, but also for camping out in an idyllic setting with such creative & motivated folk.

"Cob" is a composite of clay, sand, and fiber, formed into a monolithic wall structure. The word originally meant "round," or a round blob of said composite.

This material is astoundingly well suited to homes - I'm amazed that it is so "new" to North Americans. Earthquake resistance is far superior to most other building types. Thermal mass makes for excellent energy efficiency in heating and cooling. There are 2000 year old, ten story tall cob buildings in Yemen which still serve their occupants adequately. There are oodles and scads of millenium old cob houses across Europe.

These things are inexpensive to build and take very little skill. I suspect we Americans have forgotten them simply because we've no way of making a profit from them.

I'm curios: does anyone on this forum dwell in a cob or other earthen housing?
 

Gadget

Joined Jan 10, 2006
614
No, although I have worked in a few. Total pig to renovate, ceilings get increadibly dusty, and nigh impossible to rewire.
Another fad here is hay or straw bale houses. Also a cow to work on.
Hebal (or airated concrete) is starting to become very popular however.
 

Thread Starter

thingmaker3

Joined May 16, 2005
5,084
There was one building in the complex which had been re-wired. I could tell because they were unable to match plaster after firring out a channel for the new wire!

Tell me, Gadget, do the New Zealanders use direct burial cable in the walls, or regular old NM type? Or is conduit layed?

The folk teaching have been experimenting for five years with combining straw-bale and cob together. They use cob-lined straw bale walls in the North and West for maximum insulation, and cob-only walls in the south and east for maximum advantage of thermal mass. Bales in the hybrid walls are laid with the straw running vertically, and the bales are compressed horizontally by either cob pillars or plywood forms. Any gaps or voids are filled with cob, and the interior is covered with 75mm to 150mm of cob. Bale exteriors are covered directly with plaster.

Adobe certainly is a good material in geologically stable areas! Here in the "Pacific Ring Of Fire," however, any brick building would be shaken to rubble in short order.

Another technique shown during the workshop was to incorporate adobe-like bits into the wall interior to reduce wall drying time. Uneven surfaces on the bits, and dunking quickly in water just prior to incorporation, allow the bits to be fully integrated into the monolith composite.
 

Gadget

Joined Jan 10, 2006
614
In these styles of building, normal 3 core 2.5mmTPS is run inside plastic conduit. Normal housing uses unprotected TPS inside the walls, and a special (Purple) TPS is required when running thru polystyrene due to reactions between normal white TPS and the poly. Would have to get any more detail from one of the other guys at work, as I am the resident Electronics tech, not one of the sparkies.
Most houses here are Brick, or Wood and concrete foundations with wooden framing with appropriate bracing and trussed metal clad roofs. We are on the ring of fire here too, and everything seems to work OK. The last 7.1 (2 years back) put a crack thru my foundations, but apart from scaring me outside at 2 am, did no other real damage...(to housing anyway). Shelves were a different story.
 

Dave

Joined Nov 17, 2003
6,970
My wife and I just spent some time in a temperate rain-forest learning to build cob housing. The workshop was quite enjoyable, not only for skills learned, but also for camping out in an idyllic setting with such creative & motivated folk.

"Cob" is a composite of clay, sand, and fiber, formed into a monolithic wall structure. The word originally meant "round," or a round blob of said composite.

This material is astoundingly well suited to homes - I'm amazed that it is so "new" to North Americans. Earthquake resistance is far superior to most other building types. Thermal mass makes for excellent energy efficiency in heating and cooling. There are 2000 year old, ten story tall cob buildings in Yemen which still serve their occupants adequately. There are oodles and scads of millenium old cob houses across Europe.

These things are inexpensive to build and take very little skill. I suspect we Americans have forgotten them simply because we've no way of making a profit from them.

I'm curios: does anyone on this forum dwell in a cob or other earthen housing?
My missus wants to live in one of those houses that Hobbit's live in! Does that count! :D:p

Dave
 

Thread Starter

thingmaker3

Joined May 16, 2005
5,084
IIRC, a hobbit style home would be classed as "underground housing."

I do have two designs for 7' (3.3m) dia doors, but my wife has yet to approve either...
 

Dave

Joined Nov 17, 2003
6,970
Lol!! I love it! :D

Wait till I show here that website later, we may have only recently moved house but I'm sure she will want to move again immediately!

IIRC, a hobbit style home would be classed as "underground housing."

I do have two designs for 7' (3.3m) dia doors, but my wife has yet to approve either...
So we would be classified as vermin?!

I would like to see the concluding designs for your doors - having spent a large portion of the last week replacing every door in my house I am now a quasi-expert!

Dave
 

mrmeval

Joined Jun 30, 2006
833
If a profit can be made from it Americans *will* do it. Cost and ease of construction, ease of maintenance, aesthetics ( esthetics?) and adherence to building codes are all factors.

There are specialized builders who will make what you want within those constraints though it will cost you. They make lots of money catering to people wanting the unique, unusual, sustainable or bizarre.
 

Dave

Joined Nov 17, 2003
6,970
If a profit can be made from it Americans *will* do it. Cost and ease of construction, ease of maintenance, aesthetics ( esthetics?) and adherence to building codes are all factors.

There are specialized builders who will make what you want within those constraints though it will cost you. They make lots of money catering to people wanting the unique, unusual, sustainable or bizarre.
Property is the new 'easy profit', which is a rolling bandwagon here in the UK too. The funny thing is, that some people think it is a fast way to make £5000 a week...interesting to see that the situation is no different elsewhere around the world.

Dave
 

n9352527

Joined Oct 14, 2005
1,198
Incidentally, she loved it! We move next week! :D

Dave
You can have hobbit themed house warming party :D

I have to confess I love that house as well. Such creativity and implementation! Probably not very practical, but who cares when living in a house like that :p
 

Dave

Joined Nov 17, 2003
6,970
You can have hobbit themed house warming party :D
Good idea. No one above 4-foot is invited! :D

I have to confess I love that house as well. Such creativity and implementation! Probably not very practical, but who cares when living in a house like that :p
Couldn't agree more, the whole project reminds me of Grand Designs on Channel 4. One thing I couldn't decipher is does the house have any form of electricity supply? Since it is an "eco-house" one suspects that it is not conneted to the traditional mains-supply, but I couldn't see if it had a biofuel generator - I wouldn't be surprised.

Considering how cheap it was to make, I wonder in the current property climate, what is its market value.

Dave
 
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