Hempcrete is a mixture of hemp hurds (shives) and lime (possibly including natural hydraulic lime, sand, pozzolans or cement) used as a material for construction and insulation. It is marketed under names like Hempcrete, Canobiote, Canosmose, and Isochanvre. Hempcrete is easier to work with than traditional lime mixes and acts as an insulator and moisture regulator. It lacks the brittleness of concrete and consequently does not need expansion joints.
The typical compressive strength is around 1 MPa, around 1/20 that of residential grade concrete. Hempcrete walls must be used together with a frame of another material that supports the vertical load in building construction, as hempcrete's density is 15% that of traditional concrete.
Like other plant products, the hemp crop absorbs carbon dioxide gas as it grows, retaining the carbon and releasing the oxygen. 165 kg of carbon can be theoretically absorbed and locked up by 1 m3 of hempcrete wall during manufacture.
Limecrete, Ltd. (UK) reports a fire resistance rating of 1 hour per British/EU standards.
- Allin, Steve. Building with Hemp, Seed Press, 2005, ISBN 978-0-9551109-0-0. (p. 146, 1st Edition).
- "NNFCC Renewable Building Materials Factsheet: An Introduction". National Non-Food Crops Centre. February 21, 2008. Retrieved 2011-02-16.
- Priesnitz, Rolf B. (March–April 2006). "Hemp For Houses". Natural Life Magazine.
- "Tradical Hemcrete 2008 Information Pack". American Lime Technology. Retrieved 2009-08-25.
- Flahiff, Daniel (August 24, 2009). "Hemcrete®: Carbon Negative Hemp Walls". Inhabitat.
- "Tradical Hemcrete 2008 Information Pack". American Lime Technology. Retrieved 2010-05-15.
- Abbott, Tom (2014-04-26). "Hempcrete Factsheet". The Limecrete Company, Ltd.
- Hemcrete application data from Limetechnology