thumb|Example use of light clay within a timber frame before rendering '''Light clay''' (also '''light straw clay''', '''light clay straw''', '''slipstraw''') is a natural building material used to infill between a wooden frame in a timber framed building using a combination of clay and straw, woodchips or some other lighter material.
==History== A mixture of clay and straw was used as an infill material for timber framed building from at least the 12th century in Germany and elsewhere in Europe.<ref>{{Cite web |last=Andresen |first=Frank |title=An Introduction to Traditional and Modern German Clay Building |url=http://www.networkearth.org/naturalbuilding/clay.html |website=NetWorks Productions |quote=Building with clay has a long tradition in Germany and other European countries. Framed structures (half-timbered houses) from the 12th century, filled with a mixture of clay and straw fibers, still exist. |department=Natural Building Colloquium Southwest}}</ref> The term "light clay" or "light straw-clay" derives from the German name {{lang|de|Leichtlehmbau}} {{gloss|light clay construction}}.<ref>{{Cite book |last=Doleman |first=Lydia |title=Essential Light Straw Clay Construction |date=June 22, 2017 |publisher=New Society Publishers |isbn=978-0865718432}}</ref> Renewed interest in traditional building methods developed from the 1980s after which various natural building architects and builders started promoting the use of light clay.<ref name="art">{{Cite book |last=Kennedy |first=Joseph F. |url=https://books.google.com/books?id=054_i8KdcCAC&q=%22light+clay%22+natural&pg=PA167 |title=The art of natural building: design, construction, resources |last2=Wanek |first2=Catherine |last3=Smith |first3=Michael G. |publisher=New Society Publishers |year=2002 |isbn=978-0-86571-433-5 |pages=165–170}}</ref> An appendix for light straw-clay was added to the International Residential Code beginning with the 2015 edition.<ref>{{Cite web |last=Hammer |first=Martin |date=25 April 2017 |title=Update on Strawbale and Light Straw-Clay Codes in the United States |url=https://www.thelaststraw.org/275258-2/ |access-date=26 July 2024 |website=The Last Straw}}</ref>
==Usage== thumb|right|Light clay mixture consisting of clay, water and straw before application Local clay, often local subsoil, is mixed into a slurry with water and then combined with straw or wood chip or other similar material. Wood chips can vary in size from sawdust to {{convert|5|cm}} in diameter.<ref name=art/> The ratio of clay to other ingredients can be adapted to either increase thermal mass or insulation properties.<ref>{{Cite book |last=Chiras |first=Daniel D. |url=https://books.google.com/books?id=z_Y2AObA-joC&q=light+clay+natural&pg=PA250 |title=The natural house: a complete guide to healthy, energy-efficient |publisher=Chelsea Green Pub. |year=2000 |isbn=978-1-890132-57-6 |page=250}}</ref> The mixture is provided with additional structural strength using wattles. When used externally it can be protected with a Lime render or a clay render.<ref>{{Cite web |title=Earth in non-loadbearing walls |url=http://www.earthbuilding.info/gb/03_material/03-3c_building_techniques.htm |website=Dachverband Lehm |language=en |trans-website=German Association for Building with Earth}}</ref> A plaster or render yields a smooth, finished appearance.
==See also== * Adobe * Cob * Wattle and daub * Wychert
==References== {{reflist}}
Category:Soil-based building materials Category:Sustainable building Category:Appropriate technology Category:Natural materials Category:Sustainable products