I've been reading a lot about cob housing and I must say it sounds too good to be true. Has anyone tried this method, either in a house or maybe to make an outdoor oven? Also, since I know no authorities would give a permit for this kind of housing, just so I know a ballpark figure, what's the maximum size building you can build in your area and not have a permit? I was thinking maybe a few very small buildings linked together by breezeways. Any suggestions?

-- Elizabeth (lividia66@aol.com), November 19, 2001

Answers

here,, the biggest,,without a permit,, is 12 x 12 without concrete floor

-- stan (sopal@net-port.com), November 19, 2001.

Now, I'm not one to advise someone to stretch the letter of the law, but I will say that at a class on sustainable agriculture we go to talking about living off the grid and the like...anyway someone made the point that if you don't need to hook up to the grid then you can by-pass the building codes altogether. Here in NC, the big threat that building inspectors can use to make you comply to codes is that without their go-ahead you can't get the power turned on. Now, if you need a loan you'll need to get a permit, and I've never looked into what happens if someone reports you to the health department about septic...but if you document that you have a proper septic system(say, videotape it being installed) and you're not building in the middle of town and you don't need to hook up to the grid, then who's to say what you build? I've also heard the other side of the new-building coin is that alot of times if you can prove to your local permit office that you are not an idiot, but you are building your house in a traditional, albeit not usual fashion, that sometimes they'll glance away from their stick-built guidelines and let you stretch the limits. That might actually be worth a try. Good luck!!!!

-- gilly (wayoutfarm@skybest.com), November 19, 2001.

Elizabeth, What is a "permit"-----an expensive piece of paper that they are holding YOU hostage with! Patent & post your land. Is it not time to generate your own electricity.??

-- Jim-mi (hartalteng@voyager.net), November 19, 2001.

Elizabeth, I'm intrigued by the concept of cob housing. HOwever, it may indeed be too good to be true. If the promoters tell you that cob has good insulative value, don't believe anything they tell you. It doesn't. It has lots of other good features, but high R value isn't one of them.

JOJ

-- joj (jump@off.c), November 19, 2001.

JOJ--good point...Even at a foot thick what is the R value of that much wood????...Hard to heat?????.

-- Jim-mi (hartalteng@voyager.net), November 19, 2001.

Jim mi, cob is built with mud and straw, not wood. Where are your numbers comming from?

-- mitch hearn (moopups@citlink.net), November 19, 2001.

What is cob housing? It sounds like corn cobs but then the other dude said it is made out of mud and straw. is this a house you would live in or is it something else you are doing with it?

-- teejae (zachdawg@webtv.net), November 19, 2001.

Thanks Mitch........I stand corrected! must have been having a senior momment......I was thinking about "cordwood" .......Still both would take lots of BTU's!

-- Jim-mi (hartalteng.net@voyager.net), November 19, 2001.

There have been building permits issued on the state of Oregon for Cob homes. Once you get a cob house heated, it stay warm for a very long time. Also build yourself a heating chamber at the same time. I have the book by Becky Bee and it is truly informative. A friend of mine built a fireplace with it and it cooks a mean pizza

-- Laura (LauramLeek@yahoo.com), November 20, 2001.

JIM-MI....A 12" CORDWOOD WALL WOULD HAVE ENOUGH R-VALUE TO MEET CODE.REMEMBER LOG CABINS HAVE ABOUT A 4"-6" OVERLAP AND THEY PASS. PLUS A 1991 STUDY CONDUCTED BY THE NATIONAL STANDARDS BOARD FOR THE NATIONAL ASSOCIATION OF HOME BUILDERS.AND APPARENTLY ACCEPTED BY HUD.

CEDAR.........R=3.78 PER INCH DOUGLAS FIR...R=3.00 PER INCH LARCH.........R=3.00 PER INCH TAMARACK......R=3.00 PER INCH HEMLOCK.......R=3.58 PER INCH FIR...........R=3.58 PER INCH SPRUCE........R=3.58 PER INCH PINE..........R=3.58 PER INCH REDWOOD.......R=3.58 PER INCH SOUTHERN PINE.R=2.76 PER INCH

SO JIM-MI THE ANSWER APPEARS TO BE .YOU CAN GET UP TO R=34.4+ FROM A 12' LOG.[COB OR STRAW BALE CAN`T TOUCH THIS.PLUS I CAN PRODUCE A 24" CORDWOOD WALL WITH R=90-120 EASILY.PLUS NO COB OR STRAW BALE HAS HIT THE 1000 YEAR MARK TO MY KNOWLEDGE.]

CORDWOODGUY

-- CORDWOODGUY (cordwoodguy@n2teaching.com), November 20, 2001.

Don't shout Cordwoodguy -- it's not polite!!

MissJudi

-- MissJudi (jselig@clemson.edu), November 20, 2001.

Miss Judi, please visit this thread: http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=0074fj

for an explanation of WHY Cordwoodguy NEEDS to use all caps.

-- Joy F [in So. Wisconsin] (CatFlunky@excite.com), November 20, 2001.

Laura, the ability for cobb structures to stay hot once you get them hot is a measure of their thermal mass, not their insulative properties.

Other materials with high thermal mass are adobe, concrete, rock, etc. They all have very low R values. Hence, they are not recommended unless the climate allows them to be heated during the day by exceptionally high frequency of sunny winter days. In summer, in dry climate, they are excellent, as the nights tend to be cool enough to provide comfort during the day.

In most climates, you'll be using an exceptional amount of fuel trying to heat a cobb house, unless you deal with its low insulation values by incorporating other types of insulation.

CORDWOOD GUY, I'M INTRIGUED BY YOUR FIGURES FOR R VALUES OF WOOD. AS A BUILDER, I'VE ALWAYS USED A FIGURE OF 1.25 PER INCH AS THE R VALUE FOR SOFT WOODS. I'VE HEARD THAT CEDAR IS SOMEWHAT HIGHER, WHICH MAKES SENSE, AS IT HAS LOWER DENSITY THAN MOST WOOD, BUT HAVE NO SUPPORTING DATA.

I JUST TRIED TO FIND DATA ON THIS ON THE NET, AND ALL I COULD COME UP WITH WAS 1.25 FOR SOFTWOODS IN GENERAL, AND 1.33 FOR CEDAR.

EVEN IF YOU ASSUME SOFTWOODS ARE 1.33 PER INCH, CORDWOOD CAN MAKE AN EXTREMELY WELL INSULATED STRUCTURE!

I HAVE TO TELL YOU THAT, ACCORDING TO EVERY REFERENCE I KNOW OF, INCLUDING STATE OF OREGON ENERGY CODES, STUDS ARE CONSIDERED A THERMAL BRIDGE, BECAUSE THEIR R VALUE IS SO MUCH LOWER THAN, SAY, FIBERGLASS. (WHICH HAS AN R VALUE OF APPROXIMATELY 3 PER INCH) YOUR DATA IS THE OPPOSITE OF THIS. WHY DO YOU THINK YOUR DATA IS SO DIFFERENT?

JOJ

-- joj (jump@off.c), November 20, 2001.

I DID A BIT MORE RESEARCH ON R VALUES. EVEN THE Western Red Cedar Lumber Association STATES ON THEIR WEBSITE, http://www.wrcla.org/spec/dh/physical.html THAT "The R value ( the reciprocal of k) for Western Red Cedar is 1.35/in. of thickness. "

I WISH YOUR R VALUES WERE RIGHT. I'D HAVE BUILT A LOT OF STRUCTURES VERY DIFFERENTLY OVER THE YEARS.

JOJ

-- joj (jump@off.c), November 20, 2001.

Cordwoodguy -- sorry.

Have you tried going into "Edit", to "Preferences" and changing the fonts there??

MissJudi

-- MissJudi (jselig@clemson.edu), November 20, 2001.

There are a couple of cob houses going up here in New England this year; I'm eager to hear how they do over the winter.

From what I've read about the cob building process, it would be difficult for one or two people to build anything but a very small house anyway, if you plan to get it finished in one year. It seems to be very labor-intensive (you trade cheap materials for labor in most any inexpensive building method, I think).

Someone asked above what cob is. It's a very old method of building houses out of earth mixed with straw (or some other organic fiber). It is monolithic (unlike adobe blocks, which use the same material) and therefore quite strong. The walls are normally load-bearing, and extremely thick, often two or three feet thick at the bottom, tapering a little to the top. It basically has no R-value, so it's usefulness in a cold climate is dubious. There are thousands of cob houses in England that are hundreds of years old and still in use, but for the most part England has a milder climate than most of the United States and Canada -- and the British seem to tolerate chillier houses than we do!

Hope this helps.

-- Kathleen Sanderson (stonycft@worldpath.net), November 21, 2001.

Cob is as easily insulated as any other building material. It is made of free materials from the earth. It is FIREPROOF! Most cob houses which are built properly last for hundreds and hundreds of years. Earth is the most common method of builing in the world! Yes, it is true that north america is cold, but if you insulate your house well, you can keep it warm for a long time once you heat it. If you can not get it to meet code, get a fire permit and a built in a cob stove, fireplace, woodstove... blankets are good! Plus, there are always ways around these things. Generators for electricity, or a friend with electric knowlege. There is always the issue of keeping a small trailor or something on your property that does meet code in order to get electricity to your property to begin with. There are ways around these things. ...If you are inventive, which you probably are if you are thinking about sculpting yourself a home! What is all of this about cordwood in response to a question about cob? Is someone trying to sell wood? Just a question.

-- Tara Star Laverdiere (hesaphina@hotmail.com), January 29, 2002.

Have you considered papercrete or pacob (paper+cob), used in a cob way?

Bill

-- Bill (bill.berggren@padobe.com), March 19, 2002.