Hempcrete - Wikipedia, the free encyclopedia

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Construction block made with hemp

Hempcrete is a mixture of hemp hurds (shives) and lime (possibly including sand, pozzolans or cement) used as a material for construction and insulation.^[1] It is marketed under names like Hemcrete, Canobiote, Canosmose, and Isochanvre.^[2] Hempcrete is easier to work than traditional lime mixes and acts as an insulator and moisture regulator. It lacks the brittleness of cement and consequently does not need expansion joints.^[2]

However, the typical compressive strength is around 1 MPa^[3], over 20× lower than low grade concrete. Hempcrete walls must be used together with a frame of another material that supports the vertical load in building construction. Hempcrete's density is 15% of traditional concrete, as well as carbon negative.^[4]

Hempcrete is considered "carbon negative". Like other plant products, the hemp crop absorbs CO₂ gas as it grows, retaining the carbon and releasing the oxygen. 165kg of carbon can be theoretically absorbed and locked up by 1m³ of hempcrete wall over many decades.^[5]

[edit] References

1. ^ "NNFCC Renewable Building Materials Factsheet: An Introduction". National Non-Food Crops Centre. February 21, 2008. http://www.nnfcc.co.uk/publications/nnfcc-renewable-building-materials-factsheet-an-introduction. Retrieved 2011-02-16. 
2. ^ ^{a b} Priesnitz, Rolf B. (March/April 2006). "Hemp For Houses". Natural Life Magazine. http://www.naturallifemagazine.com/0604/hemphouse.htm. 
3. ^ "Tradical Hemcrete 2008 Information Pack" (PDF). American Lime Technology. http://www.americanlimetec.com/tech_sheets.php?file=PDF_file&recid=12.21&h=447447697558567941. Retrieved 2009-08-25. 
4. ^ Flahiff, Daniel (August 24, 2009). "Carbon Negative Hemp Walls are 7x Stronger than Concrete". Inhabitat. http://www.inhabitat.com/2009/08/24/hemcrete-carbon-negative-hemp-walls-7x-stronger-than-concrete/.  (Despite the article title, the "7x stronger" claim does is contradicted by the text: "Hemcrete® is not stronger than concrete.")
5. ^ "Tradical Hemcrete 2008 Information Pack" (PDF). American Lime Technology. http://www.americanlimetec.com/tech_sheets.php?file=PDF_file&recid=12.21&h=447447697558567941. Retrieved 2010-05-15. 

[edit] External links

• Hemcrete application data from Limetechnology

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Categories: Appropriate technology | Building materials | Concrete | Hemp | Masonry

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