Core-and-veneer

Core-and-veneer, brick and rubble, wall and rubble, ashlar and rubble, and emplekton all refer to a building technique where two parallel walls are constructed and the core between them is filled with rubble or other infill, creating one thick wall.{{Cite book|author=Vitruvius|authorlink=Vitruvius|chapter=II.8.7|title=De architectura (On Architecture)}} Originally, and in later poorly constructed walls, the rubble was not consolidated. Later, mortar and cement were used to consolidate the core rubble and produce sturdier construction.

Modern masonry still uses core and veneer walls; however, the core is now generally concrete block instead of rubble, and moisture barriers are included.{{Cite web|author=Weber, Richard A.|date=19 February 2013|title=Building Envelope Design Guide – Masonry Wall Systems|work=Whole Building Design Guide|publisher=National Institute of Building Sciences|url=http://www.wbdg.org/design/env_wall_masonry.php|archiveurl=https://web.archive.org/web/20130314154143/http://wbdg.org/design/env_wall_masonry.php|archivedate=14 March 2013|url-status=live}} Often such walls end up as cavity walls by the inclusion of space between the external veneer and the core in order to provide for moisture and thermal control.

History

=Greeks and Phoenicians=

Both the early Phoenicians and Greeks used rubble-filled masonry walls.{{Cite journal|author=Sharon, Ilan|year=1987|title=Phoenician and Greek Ashlar Construction Techniques at Tel Dor, Israel|journal=Bulletin of the American Schools of Oriental Research|volume=267|issue=267|pages=21–42|jstor=1356965|doi=10.2307/1356965}}{{Cite web|title=Monuments and Archaeological Sites (Lesvos, Greece)|year=2011|url=http://www.petrifiedforest.gr/NEW%20pf/application/MONUMENTS%20&%20ARCHAEOLOGICAL%20SITES.pdf|archiveurl=https://web.archive.org/web/20140502004923/http://www.petrifiedforest.gr/NEW%20pf/application/MONUMENTS%20%26%20ARCHAEOLOGICAL%20SITES.pdf|archivedate=2 May 2014|url-status=dead|df=dmy-all|access-date=13 August 2017}} The word emplekton was borrowed from Greek ἔμπλεκτον and originally meant "rubble" but came to apply to the construction technique as well.{{Cite book|author=Schofield, Richard V.|year=2009|chapter=Glossary: emplekton|title=On architecture by Vitruvius|location=London|publisher=Penguin|pages=171–172|isbn=978-0-14-144168-9}}

=Romans=

The Romans started with basic emplekton masonry walls,{{Cite book|author=Dennis, George|authorlink=George Dennis (explorer)|year=1848|chapter=Emplecton masonry|title=The Cities and Cemeteries of Etruria|publisher=John Murray|location=London|chapter-url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Places/Europe/Italy/_Periods/Roman/Archaic/Etruscan/_Texts/DENETR*/4.html#App.1}} but developed the technique further using temporary walls (forms) that were removed after the cemented rubble (concrete) had cured. This technique was called opus caementicium, and eventually led to modern ferroconcrete construction.{{Cite web|author=Caviasca, Massimiliano|year=2008|title=L'evoluzione della tipologia e la materia costruttiva: il muro a emplecton|language=Italian|publisher=Politecnico di Milano (Polytechnic University of Milan)|url=http://docenti.polimi.it/caviasca/caviasca/lez4.pdf|archiveurl=https://web.archive.org/web/20140502020531/http://docenti.polimi.it/caviasca/caviasca/lez4.pdf|archivedate=2 May 2014|url-status=dead|access-date=2 May 2014}}

=India=

The buildings of the Taj Mahal are constructed with walls of brick and rubble inner cores faced with either marble or sandstone locked together with iron dowels and clamps. Some of the walls of the mausoleum are several metres thick. {{Cite book| last = Koch| first = Ebba| year = 2006| title = The Complete Taj Mahal: And the Riverfront Gardens of Agra| publisher = Thames & Hudson| location = London| page = [https://archive.org/details/completetajmahal0000koch/page/97 97]| isbn = 978-0-500-34209-1| url = https://archive.org/details/completetajmahal0000koch/page/97}}

=Ancestral Puebloans=

File:Chacoan Masonry types by Stephen H. Lekson.png

In the large complexes at Chaco Canyon, the Ancestral Puebloans used the wall and rubble technique, with walls of carefully shaped sandstone.{{Cite encyclopedia|author=Reed, Paul F.|year=2008|title=An Overview of the Archaeology of Chaco Canyon|editor1=McManamon, Francis |editor2=Cordell, Lind |editor3=Lightfoot, Kent |editor4=Milner, George |encyclopedia=Archaeology in America: An Encyclopedia|volume=3|page=[https://books.google.com/books?id=arfWRW5OFVgC&pg=RA2-PA72 72]|location=Westport, Connecticut|publisher=Greenwood Press|isbn=978-0-313-33187-9}} The Ancestral Puebloans used mud as their mortar, both with the veneer and to consolidate the core.{{Cite web|title=Masonry of the Southwest|publisher=United States National Park Service|url=https://www.nps.gov/museum/exhibits/chcu/slideshow/masonry/masonintro.html|archive-url=https://web.archive.org/web/20120619180608/http://www.nps.gov/museum/exhibits/chcu/slideshow/masonry/masonintro.html|archive-date=19 June 2012|url-status=live}} This core and veneer technique was also used at other Ancestral Puebloans sites outside of Chaco Canyon.{{Cite web|author=Cameron, Catherine|title=The Bluff Great House and the Chaco Phenomenon|publisher=Arizona Archaeological and Historical Society|url=http://www.az-arch-and-hist.org/2010/09/catherine-cameron-the-bluff-great-house-and-the-chaco-phenomenon/|archiveurl=https://web.archive.org/web/20140501230413/http://www.az-arch-and-hist.org/2010/09/catherine-cameron-the-bluff-great-house-and-the-chaco-phenomenon/|archivedate=1 May 2014|url-status=live}} Later pueblos used mud bricks (adobe) for the veneer.

=Mayan=

In the Puuc region, and as far south as at least Tikal, the Mayans developed core-and-veneer walls to the point where, by the classic period, they were filled with concrete.{{Cite book|author=Yant, Anna Catesby|year=2011|title=Powerful buildings: The evolution of non-domestic architecture and social interaction in the Puuc|series=Dissertations|publisher=Vanderbilt University|page=133|url=http://etd.library.vanderbilt.edu/available/etd-03222011-144930/unrestricted/YantDissertation2011.pdf|archiveurl=https://web.archive.org/web/20140501231157/http://etd.library.vanderbilt.edu/available/etd-03222011-144930/unrestricted/YantDissertation2011.pdf|archivedate=1 May 2014|url-status=live}}{{Cite web|author=Andrews, George F.|year=2012|title=Architectural survey Tikal, Guatemala: the great temples|url=http://repositories.lib.utexas.edu/bitstream/handle/2152/15343/txu-aaa-gfa00352.txt?sequence=3|archiveurl=https://web.archive.org/web/20140501231606/http://repositories.lib.utexas.edu/bitstream/handle/2152/15343/txu-aaa-gfa00352.txt?sequence=3|archivedate=1 May 2014|url-status=live}}{{Cite book|author=Andrews, George F.|year=1999|title=Pyramids, Palaces, Monsters and Masks: The Golden Age of Maya Architecture, Volume 1, Architecture of the Puuc region and the northern plains areas|publisher=Labyrinthos Press|location=Lancaster, California}}

Problems

Traditional core-and-veneer walls suffered from moisture migration and thermal expansion and contraction.{{Citation|author1=Martinez, M. |author2=Carro, G.|year=2007|title=Ancient building requirements and the evaluation of different lime-cement mortars compositions|work=2º Congresso Nacional de Argamassas de Construção|publisher=Associação Portuguesa dos Fabricantes de Argamassas de Construção|location=Lisbon|url=http://www.apfac.pt/congresso2007/comunicacoes/Paper%2081_07.pdf}} They had a low tensile strength, hence a poor resistance to twisting or stretching.{{Citation|author1=Valcárcel, J. P. |author2=Martín, E. |author3=Domínguez, E. |author4=Escrig, F. |year=2001|title=Structural modelling of medieval walls|editor=Lourenço, P. B. |editor2=Roca, P.|work=Historical Constructions|publisher=Guimarães|url=http://www.civil.uminho.pt/masonry/Publications/Historical%20constructions/page%20501-510%20_2_.pdf|archiveurl=https://web.archive.org/web/20070821165635/http://www.civil.uminho.pt/masonry/Publications/Historical%20constructions/page%20501-510%20_2_.pdf|archivedate=21 August 2007|url-status=live}} Tensile strength was increased by increasing the width of the walls or by providing masonry "piers" (vertical columns or ribs), either inside the wall or as additional exterior support.{{Cite journal|author1=Sugiyama, Tomoyasu |author2=Ota, Naoyuki |author3=Nunokawa, Osamu |author4=Watanabe, Satoshi |year=2006|title=Development of Quakeproof Reinforcement Methods for Masonry Walls|journal=Quarterly Report of RTRI|volume=47|issue=2|pages=105–110|doi=10.2219/rtriqr.47.105|doi-access=free}}

Notes

External links

{{Cite web|title=Figure 14. The large number of stones used, requires strong and stable scaffolding inside the building.|work=Contribution to the medieval building technology based on the reconstruction of a rounded church|publisher=EXARC|url=http://exarc.net/files/styles/large/public/figure-14.jpg|archiveurl=https://web.archive.org/web/20140502013106/http://exarc.net/files/styles/large/public/figure-14.jpg|archivedate=2 May 2014|url-status=dead|access-date=2 May 2014}} shows construction and cross-section of core-and-veneer wall
{{Cite web|title=Drystone Walls in England|publisher=Britain Express|url=http://www.britainexpress.com/History/drystone.htm|archiveurl=https://web.archive.org/web/20130810073530/http://www.britainexpress.com/History/drystone.htm|archivedate=10 August 2013|url-status=live}} showing cross-section of a core-and-veneer wall.

Category:Masonry

Category:Construction

Category:Types of wall