Editing Cob (material) (section)

==History and usage==
[[File:Cob stitch copy.jpg|thumb|"Cob stitch" repair on old traditional cob cottage in [[Devon]], England]]
[[File:Maison de Jeanne, Sévérac-le-Château.jpg|thumb|[[Maison de Jeanne]], Sévérac-le-Château. Timber and cob construction]]
''Cob'' is an English term attested to around the year 1600<ref>"cob, n2. 1." ''Oxford English Dictionary'' 2nd. ed. 2009. CD-rom.</ref> for an ancient building material that has been used for building since prehistoric times. The use of this material in Iran is more than 4000 years old. The etymology of ''cob'' and ''cobbing'' is unclear, but in several senses means to ''beat'' or ''strike'',<ref>{{cite web|title=cob |url=https://www.collinsdictionary.com/dictionary/english/cob |website=Collins English Dictionary|publisher=HarperCollins|access-date=13 January 2017|quote=verb: ''(transitive) British informal'' to beat, esp on the buttocks}}</ref> which is how cob material is applied to a wall.

Many similar materials and methods of earthen building are used around the world, such as ''[[adobe]]'',<ref name=Rapp>Rapp, George Robert. "Unbaked clay or mud", ''Archaeomineralogy''. 2nd ed. Berlin: Springer, 2009. Print.</ref> ''lump clay'',<ref name=Rapp/> ''[[Puddling (engineering)|puddled]] clay'', ''chalk mud'',<ref name=Rapp/> ''[[wychert]]'',<ref name=Rapp/> ''clay daubins'',<ref name=Rapp/> ''swish'' ([[Asante Twi]]),<ref>{{cite web|last1=Oliver|first1=Paul|last2=Hess|first2=Janet B.|title=African architecture|url=https://www.britannica.com/art/African-architecture#ref519949|website=Encyclopædia Britannica|access-date=13 January 2017|date=23 February 2012}}</ref> ''torchis'' (French),<ref name=CL>Edwards, Jay Dearborn, and Nicolas Verton. "mud with straw", ''A Creole Lexicon Architecture, Landscape, People''. Baton Rouge: Louisiana State UP, 2004. Print.</ref> ''bauge'' (French),<ref name=CL/> ''bousille'' (French mud with moss),<ref name=CL/> beaten clay-''pahsa'' (Central Asia), and ''cat and clay''.<ref>[http://www.merriam-Webster.com/dictionary/cat%20and%20clay "cat and clay" Websters Online Dictionary accessed March 23, 2015.]</ref>

Cob structures can be found in a variety of climates across the globe. European examples include:

* in England, notably in the counties of [[Devon]] and [[Cornwall]] in the [[West Country]], and in [[East Anglia]] (where it is referred to as ''clay lump'')<ref>{{cite web|last1=Bouwens|first1=Dirk|title=Earth Buildings and Their Repair|url=https://www.buildingconservation.com/articles/earth/earth_buildings.htm |website=buildingconservation.com |publisher=Cathedral Publications Ltd.|access-date=13 January 2017}} ''[reproduced from The Building Conservation Directory, 1997]''</ref>
* in Wales, notably in rural [[Anglesey]]<ref>{{cite book|title=The Architecture of Wales From the First to the Twenty-First Century|page=13|year=2018|last=Hilling|first=John B.|publisher=University of Wales Press|isbn= 9781786832856}}</ref>
* in [[Donegal Bay]] in [[Ulster]] and in Munster, South-West [[Ireland]]{{citation needed|date=July 2016}}
* in [[Finistère|Finisterre]] and Ille-et-Vilaine in [[Brittany]], where many homes have survived over 500 years and are still inhabited{{citation needed|date=September 2010}}

Some of the oldest human-made structures in Afghanistan are composed of [[rammed earth]] and cob.<ref>{{cite news |last=McArdle |first=Patricia |title=Afghanistan's Last Locavores |url=https://www.nytimes.com/2011/06/20/opinion/20mcardle.html?_r=2 |newspaper=[[The New York Times]] |date=June 19, 2011}}</ref> Cobwork (''tabya'') was used in the [[Maghreb]] and [[al-Andalus]] in the 11th and 12th centuries, and was described in detail by [[Ibn Khaldun]] in the 14th century.<ref>{{cite book |last=Routledge Hill |first=Donald |author-link=Donald Routledge Hill |editor1-last=Rashed |editor1-first=Roshdi |editor2-last=Morelon |editor2-first=Régis |year=1996 |chapter=Engineering |title=Encyclopedia of the history of Arabic science |volume=3 |isbn=0-415-02063-8 |page=766}}</ref>

Many old cob buildings can be found in [[Africa]], the Middle East, and the southwestern United States like the [[Taos Pueblo]].{{citation needed|date=September 2010}} A number of cob cottages survive from mid-19th-century New Zealand.<ref name=NZHPT>Dozens of cob cottages are [http://www.historic.org.nz/TheRegister/RegisterSearch/SearchResults.aspx?s=s&NameOrID=cob listed on the Register] of the New Zealand Historic Places Trust, e.g. {{cite web|title=Ferrymead Cob Cottage|url=https://www.heritage.org.nz/the-list/details/3101|work=Rarangi Taonga: the Register of Historic Places, Historic Areas, Wahi Tapu and Wahi Tapu Areas|publisher=New Zealand Historic Places Trust Pouhere Taonga|access-date=21 August 2013}}</ref>

Traditionally, English cob was made by mixing the clay-based subsoil with sand, straw and water using [[oxen]] to trample it. English soils contain varying amounts of [[chalk]], and cob made with significant amounts of chalk are called ''chalk cob'' or ''[[wychert]]''. The earthen mixture was then ladled onto a stone [[Foundation (architecture)|foundation]] in [[Course (architecture)|courses]] and trodden onto the wall by workers in a process known as ''cobbing''. The construction would progress according to the time required for the prior course to dry. After drying, the walls would be trimmed and the next course built, with lintels for later openings such as doors and windows being placed as the wall takes shape.<ref name="SnellCallahan2009">{{cite book |last1=Snell |first1=Clarke |last2=Callahan |first2=Tim |title=Building Green: A Complete How-to Guide to Alternative Building Methods : Earth Plaster, Straw Bale, Cordwood, Cob, Living Roofs |url= https://books.google.com/books?id=gGEbRyok6f0C&pg=PA276 |access-date=1 June 2013 |year=2009 |publisher=Sterling Publishing Company, Inc. |isbn=978-1-60059-534-9 |pages=276–}}</ref>

The walls of a cob house are generally about {{convert|24|in|cm}} thick, and windows were correspondingly deep-set, giving the homes a characteristic internal appearance. The thick walls provided excellent [[thermal mass]] which was easy to keep warm in winter and cool in summer. Walls with a high thermal mass value act as a thermal buffer inside the home.<ref>{{cite journal |last1=Goodhew |first1=Steven |last2=Griffiths |first2=Richard |year=2005 |title=Sustainable earth walls to meet the building regulations |journal=Energy and Buildings |volume=37 |issue=5 |page=1 |publisher=Elsevier |doi=10.1016/j.enbuild.2004.08.005 |bibcode=2005EneBu..37..451G |url=http://gse.cat.org.uk/downloads/Goodhew,_2005.pdf |access-date=24 January 2013 |archive-url=https://web.archive.org/web/20150110000828/http://gse.cat.org.uk/downloads/Goodhew,_2005.pdf |archive-date=10 January 2015 |url-status=dead }}</ref> The material has a long life-span even in rainy or humid climates, provided a tall foundation and large roof overhang are present

Cob is [[fireproof]],<ref>{{Cite journal |last=Cioruța |first=Bogdan |date=2016 |title=Trends In The Techniques Of Design And Building Traditional Earth Houses |url=https://www.proquest.com/docview/1856858074 |journal=Scientific Bulletin Series D: Mining, Mineral Processing, Non-Ferrous Metallurgy, Geology and Environmental Engineering |publisher=[[North University of Baia Mare]] |volume=30 |issue=2 |pages=21–31 |id={{ProQuest|1856858074}} |via=ProQuest}}</ref>{{Rp|page=28}} while "fire cob" (cob without straw or fiber) is a [[refractory material]] (the same material, essentially, as unfired common red brick), and historically, has been used to make chimneys, fireplaces, forges and crucibles. Without fiber, however, cob loses most of its tensile strength.<ref>{{Cite journal |last=Saxton |first=R. H. |date=1995 |title=The performance of cob as a building material |url=https://www.istructe.org/journal/volumes/volume-73-(published-in-1995)/issue-7/the-performance-of-cob-as-a-building-material/ |journal=The Structural Engineer |publisher=[[The Institution of Structural Engineers]] |volume=73 |issue=7 |pages=111–15}}</ref>{{Rp|page=114}}