Talk:Cob (material)

Cost of wall
Re the 4 bedroom cob house in Worcestershire - "The total construction cost was £300 000, but the metre-thick cob outer wall cost only £20 000.." I'm not sure how this compares with ordinary houses - it's expressed as though £20 000 is cheap, but how much would an ordinary wall (or a well-insulated wall) cost in a similar house? --Singkong2005 00:40, 30 May 2006 (UTC)


 * You're right, it does say it as if it's cheap, which it's not - words like "only" should really be avoided in this context as it represents a POV on what constitutes "cheap" (however if it had cited a comparison it would've been forgivable). This figure of £20,000 is probably incorrect, as it actually costs next to nothing to build a house out of cob (mud and straw is generally free! Also I've got reliable sources stating that cob houses have been built for under £1000 total cost exc. land.) even though to be fair his house was pretty extravagant. The only real cost comes from the use of timber, slate, glass, labour, equipment hire, sand, and the fact that he used shillet in his cob mix. Since the cost of these materials depends mainly on local availability of the material the price is really irrelevant anyway. On the topic of shillet, the article says that Kevin McCabe was the first person to use shillet in cob, which is plain untrue, as I have seen Cornish cob cottages with shillet cob, which was exposed when they were demolished. generally I'd say that the section on McCabe's house is pretty unencyclopedic, and would say delete it until someone can be bothered to cite it - the section doesn't really add anything to the article and what little information it contains is debateable at best. ▫Bad▫ harlick♠  02:07, 28 January 2007 (UTC)


 * Just noticed the cite for this claim, however I'm still uncomfortable with it as I don't feel that it's representative of the subject, nor is it possible for me to verify without a copy of that newspaper. So my recommendation remains "delete". ▫Bad▫ harlick♠  02:06, 31 January 2007 (UTC)

Citations?
Just put in a request for a citation with regards to cob's claimed benefits. That it's cheap or not has already been discussed here. But has anybody actually done a study stating that cob buildings are resistant to earthquakes? (And no, anecdotes don't cut it--I mean a real study.) It also seems odd to state that cob buildings are "fireproof," and then further down the page (under "Modern Cob Buildings") we have a mention of an Irish cob building that got destroyed by arson. I'd love to see some better references on this page.

Aasmith (talk) 01:55, 18 February 2008 (UTC)

Who would profit from paying for such a study? Cob walls are much thicker than masonry, and this makes them inherently more stable. Tabby (talk) 05:20, 7 March 2008 (UTC)

Expense: If labor is cheap, cob is cheap. I have been involved with the buying of cobbing materials and building cob walls. So I can say from experience that clay(clay rich soil) and sand(sand rich soil) is in very plentiful supply almost anywhere. Buying is cheap and often the materials are given away by excavators. However cobbing is in no way "inexpensive", the materials are nearly free, but the labor is not, so in reality the expense is primarily a cost of labor issue. Even with volunteer labor you still have to realize that cobbing is monitarily inexpensive but labor expensive. For example the "heart house" built by some people from The Cob Cottage Co. was constructed for under $500. It should be pointed out that the walls are easy to build, so its much more possible for ordinary folk to build a house themselves, using their own labor. So really this isn't about references, but rather about more concise language that demonstrates the specific pros and cons.

Fireproof: Cob itself does not burn, so strictly speaking the Cob wall itself IS fireproof. But there's nothing special about the roof, it could burn just like any other. So again this is more about concise language.

Earthquakes: http://seattlepi.com/lifestyle/334487_cobseattle06.html "University of British Columbia engineers tested cob's earthquake resistance and, according to one account, the test structure survived a simulated 7.4 quake with only minor cracks, even after prior shaking." Cob houses built in earthquake zones must have some adjustments made to be safe. Wall thickness is clearly a factor but its also advisable to to use a concrete bond beam both at the base of the wall and the top. —Preceding unsigned comment added by 64.112.227.142 (talk) 00:23, 2 May 2008 (UTC)

Seismic resistance of cob construction
To suggest that cob construction is resistant to earthquakes might be misleading. We recently (2010/02/27) had a significant earthquake in Chile, and all the adobe construction in an area over hundreds of kilometers long was destroyed. Adobe might not be cob, but if human life is valuable, be careful of what materials you use in earthquake prone areas. Perbjarnebro (talk) 14:25, 11 April 2010 (UTC)

Adobe
I don't really get how this is different from Adobe. — Chameleon 23:32, 27 March 2008 (UTC)
 * To my understanding, it's on two levels: one, the mix is different in creation technique and the content. Two, adobe will degrade in the rain, and is thus only really suitable for dry climates. Cob will not break down in wet weather. Van Tucky 23:44, 27 March 2008 (UTC)
 * Adobe sometimes has straw added, while cob always adds a decent amount of straw. Adobe is preformed into units and dried, before assembling into a structure, while cob is built up on the structure like sculpting. Bodhi.peace (talk) 18:19, 6 April 2008 (UTC)
 * Cob uses larger proportion of straw than adobe, it also uses longer individual straws. During the process of building a cob wall, straws are laced together by pushing a Cobbers Thumb (a stick) into the wet top layer. The longer strands of straw also creates very small airways which speed in drying, an important factor in the speed of construction. Also, cob is a reference to the building technique of tossing a small lump(cob) from person to person in a line of any length straight up to people on the wall (thus no heavy lifting or hauling equipment). —Preceding unsigned comment added by 64.112.227.142 (talk) 22:49, 1 May 2008 (UTC)

The remark that this is 'similar tp Adobe' is nonsense as the building process is different (adobe is described as to have 'bricks') + in the Cobb article it says: resistent to seismic activity'  and in the adobe article it says 'susceptible to earthquakes' So similar yes in a fact that you can live in it and that it is built with earthy materials, but in fact, a modern house is that too! — Preceding unsigned comment added by 88.159.133.234 (talk) 17:31, 21 October 2012 (UTC)

Originates in the Sahel
The article does not say that cob originates in the Maghreb. It started being used their. Limestone had been the dominate material since ancient times. Cob and adobe had been the dominant material in the Sahel. I suspect this material originates in the Sahel or west africa. 72.86.24.230 (talk) 23:32, 30 July 2010 (UTC)


 * An interesting theory – do you have any refs for it? Richard New Forest (talk) 20:29, 31 July 2010 (UTC)


 * In particular, is there any evidence that it originated in just one place? Tamped earth mixes would seem to have had multiple origins in the independent fertility of congruent great minds. JonRichfield (talk) 14:01, 12 September 2012 (UTC)

Fire Proofing
The intro alleges that cob is a fireproof material. However, the section on modern cob domiciles explicitly says that one was destroyed by an arsonist. These two facts are at the very least mildly confusing. Someone familiar with the particulars should rectify the discrepancy. —Preceding unsigned comment added by 68.105.150.56 (talk) 02:35, 15 May 2011 (UTC)

I know nothing about this consideration concerning cob, but it strikes me that many structures of fireproof material have been destroyed by the burning of non-fireproof components and (such as wooden beams) and combustible  contents. Of course, if someone happens to know the details, it would be nice to get explicit clarification. JonRichfield (talk) 14:12, 12 September 2012 (UTC)

Someone please check usage in another article?
Your description of "cob" does not gel with the article on Woodway House (note "lime" in particular). Could someone please reconcile the two? I am leaving a similar note with the Woodway House article. In particular I am interested in the distinction between the usages for the terms. I would see to it myself, but this is not my line. JonRichfield (talk) 14:12, 12 September 2012 (UTC)

Clay dabbin and Daubing
This article is lacking in a few areas and the EBUKI Clayfest Conference of 2016 has further emphasised the rarely mentioned existence of clay dabbin/daubing in the Solway Plain area. It would help correct the impression given by the article if details were added of the Solway Plain earth built structures and the method used - it clearly differed from the standard cob construction.Rosser Gruffydd 17:04, 26 July 2016 (UTC)
 * In which case maybe it isn't cob? In either case, a suitable source is required (and Dorothy Wordsworth's account, historically interesting as it undoubtedly is, isn't suitable for statements about cob buildings today). PaleCloudedWhite (talk) 17:11, 26 July 2016 (UTC)
 * That seems a narrow view - Cob material is known by many names including adobe,[6] lump clay,[6] puddled clay, chalk mud,[6] wichert,[6] CLAY DAUBINS,[6] swish (African), torchis (French),[7] bauge (French),[7] bousille (French mud with moss),[7] cat and clay[8]. Rosser Gruffydd 17:14, 26 July 2016 (UTC)
 * It's possible this article needs renaming or redefining, as there are many names and local variations of what is basically a reinforced clay structure, but in any case my point is that we need sources to verify statements. If the structures that you refer to are fundamentally similar (or fundamentally different) to cob, we need sources stating that. My objection to your addition is solely that the source you used (Dorothy Wordsworth) just can't be considered adequate. PaleCloudedWhite (talk) 17:25, 26 July 2016 (UTC)
 * For your consideration and comment - Scottish National Dictionary -

†DAUBING, vbl.n. A gathering of neighbours to build the walls of a new house. Dmf. 1795 Stat. Acc.1 II. 22–23: The manner of erecting them [houses] is singular. In the first place, they dig out the foundation of the house, and lay a row or two of stones, then they procure from a pit contiguous, as much clay or brick-earth as is sufficient to form the walls: and having provided a quantity of straw, or other litter to mix with the clay, upon a day appointed, the whole neighbourhood, male and female, assemble, each with a dung-fork, a spade, or some such instrument. . . . In this manner, the walls of the house are finished in a few hours: after which they retire to a good dinner. . . where they have music and a dance. . . . This is called a daubing.

[From Eng. daub, to smear.] Rosser Gruffydd 17:30, 26 July 2016 (UTC)


 * That seems only to support an assertion that, in Scotland at least, people coming together to erect such walls is called a daubing, though it doesn't support any statement that the actual material is called daubing. Also the process described here is fundamentally different from cob in that the walls do not appear to be built in layers with drying time between each layer. So, I'm not sure how this would fit into the article, if at all. PaleCloudedWhite (talk) 21:33, 26 July 2016 (UTC)


 * I may produce an article on Clay Dabbin / Daubing however I suspect that the consensus would call for it to be combined with this article. Rosser Gruffydd 07:34, 27 July 2016 (UTC)


 * I have added a few where most required. I note that your 19th Century definition of 'Cob' requires revision - "Cob is the use of the earthen material as a structural component". This would include the use the use of clay as a filling material in timber-frame structures... Clay dabbin would therefore be a variety of 'Cob'. Maria Yioutani-Iacovides in 'Vernacular earthen architecture'. 'Context' No.143 March 2016. Page 11. Institute of Historic Building Conservation. Rosser Gruffydd 07:55, 27 July 2016 (UTC)


 * Please note that it is not my "19th Century definition of 'Cob'", because—as is standard on Wikipedia—this article has been written by many editors. I have not been defending the rest of the article, but just objecting to Dorothy Wordsworth being used as a source for a new addition about cob buildings in existence today. PaleCloudedWhite (talk) 08:13, 27 July 2016 (UTC)

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