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ENVIRONMENTAL ARTICLE

 *This article was written with a byline for Greenhome.com and is posted here: 

http://www.greenhome.com/blog/hempcrete-sustainable-building-material-for-small-business-and-residential-use

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Hempcrete, Sustainable Building Material for Small Business and Residential Use


It has always been known that hemp, derived from the marijuana (cannabis) plant, is a super power raw material. It can be manufactured into rope, paper, shoes, clothing, makeup, food, biofuel, and much more. In fact, in 1938 Popular Mechanics magazine listed 25,000 products which could be manufactured from hemp.


Now hemp seems to have made its way into the construction industry as a sustainable, energy efficient building material called hempcrete. From small business construction companies to do-it-yourself projects hempcrete brings hope for replacing unsustainable choices. This is a material our forefathers would approve bringing back to its sustainable uses like the paper of the first draft of the Declaration of Independence and the fabric for the first American flag.


It's All in the Shiv


The shiv or the stalk of the male marijuana plant is collected and finely chopped into what are called hemp curds. These curds are mixed with water and a lime binder to form a pliable, concrete-like application that dries hard enough to be used in building homes in the form of walls, sheetrock replacement and insulation. 


The male plant is used due to its practically nonexistent THC (tetrahydrocannabinol) level, the psychoactive compound found primarily in the female plant. 


Benefits of Hempcrete


Due to its significant environmental benefits hempcrete is becoming more popular in the construction industry, particularly projects seeking Leadership in Energy & Environmental Design (LEED) approval. Hempcrete is a USA made product with highly lucrative export potential once marijuana becomes federally accepted. Until then, small American companies are producing and installing hempcrete in states where marijuana has been legalized.


According to Collective Evolution and the Huffington Post, some of the benefits of hempcrete include: 


  • Non-toxic 
  • Biodegradable 
  • Energy-efficient
  • Non off-gassing
  • Controls humidity 
  • Lighter than concrete 
  • Resistant to mold, insects and fire
  • Rapidly grows with little detrimental effect on the soil
  • Used as insulation, flooring, walls, roofing, furniture and more
  • Fire-proof, water-proof, and rot-proof (as long as it’s above ground) 
  • A 20,000lbs carbon savings when used to build a moderate sized home
  • May have a higher R-value, or thermal resistance, than concrete (which is still being studied)


Charmeuse, an Eco-friendly manufacturer of lime, high calcium limestone and dolomitic stone, describes findings of their case study on hempcrete.


“Hempcrete is easy to use and makes the isolation breathable. It provides a healthier indoor atmosphere by allowing the humidity to evacuate. Another advantage is its availability: hemp is easy to cultivate. Furthermore, it does not require chemical treatments and recaptures a large amount of CO2. It should be highlighted that hempcrete captures more CO2 than the amount emitted for its production.” 


Working Together


Hempcrete is not a replacement for concrete, just an adjunct to it. Concrete has been used for centuries but according to recent reports, alternative or replacement materials are being considered due to its environmental impact. 


According to a study cited in The Guardian,  


“Concrete is the second most used product on the planet, after water, and almost half of it is produced in China. The booming Chinese economy has created such a demand for building materials that cement production there last year released 540m tonnes of carbon dioxide - just short of Britain's total output from all sources.” 


The reports continue with one coming from the Civil Engineer’s Forum stating that concrete has,


  • Low tensile strength (compared to other building materials)
  • Low ductility
  • Low strength-to-weight ratio
  • Is susceptible to cracking


The major drawback of hempcrete is that it cannot be used as a foundation due to potential rotting. In addition, it may need several coatings and always needs a steel or wood frame to enable installation. 


Therefore concrete must be used a solid, element bearing foundation while hempcrete can easily build on top of it. This is a working together of two materials that continues to lead us to a more sustainable future in the building supply industry.



 

If you own a small construction business or are a residential weekend construction connoisseur hempcrete may be the best choice as a sustainable, inexpensive, highly available building material. It is just the tip of the iceberg of the continued leaps and bounds that the green mission is successfully being executed.