Light clay

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.[1] The term "light clay" or "light straw-clay" derives from the German name Leichtlehmbau 'light clay construction'.[2] 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.[3] An appendix for light straw-clay was added to the International Residential Code beginning with the 2015 edition.[4]

Usage

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 5 centimetres (2.0 in) in diameter.[3] The ratio of clay to other ingredients can be adapted to either increase thermal mass or insulation properties.[5] 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.[6] A plaster or render yields a smooth, finished appearance.

See also

References

  1. ^ Andresen, Frank. "An Introduction to Traditional and Modern German Clay Building". Natural Building Colloquium Southwest. NetWorks Productions. 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.
  2. ^ Doleman, Lydia (June 22, 2017). Essential Light Straw Clay Construction. New Society Publishers. ISBN 978-0865718432.
  3. ^ a b Kennedy, Joseph F.; Wanek, Catherine; Smith, Michael G. (2002). The art of natural building: design, construction, resources. New Society Publishers. pp. 165–170. ISBN 978-0-86571-433-5.
  4. ^ Hammer, Martin (25 April 2017). "Update on Strawbale and Light Straw-Clay Codes in the United States". The Last Straw. Retrieved 26 July 2024.
  5. ^ Chiras, Daniel D. (2000). The natural house: a complete guide to healthy, energy-efficient. Chelsea Green Pub. p. 250. ISBN 978-1-890132-57-6.
  6. ^ "Earth in non-loadbearing walls". Dachverband Lehm [German Association for Building with Earth].