Environmentally friendly with a quick growing cycle, hemp could become a cost-effective alternative to traditional insulation materials.
Over the last 20 years, the building industry has remained relatively unchanged. Most companies construct new buildings from old materials, like wood and concrete. Both materials come with environmental impacts. Furthermore, with rising energy prices and increasingly strict regulations calling for the reduction of energy consumption in modern buildings, companies are required to increase the levels of insulation used. Increased levels of insulation lead to increased building costs. For this reason, the building industry is looking for an alternative. Could hemp be the solution?
H E M P
In the 1600’s British colonies were compelled by law to produce hemp for cloth, sacks, canvas, paper and more. Hemp fibre was essential to the maritime industry, as the rope and fabric created from it were decay resistant. Up until the 1820s and the introduction of the cotton gin, 80 percent of all textiles were made from hemp. Henry Ford's first Model-T was built to run on hemp gasoline and the car itself was constructed with hemp panels. However, after the criminalisation of Cannabis at the beginning of the 20th Century, the hemp industry died.
Fast forward to 21st Century, hemp is set to become an industrious fibre once again. After removing the fibre-bearing cortex from the rest of the stalk, it is possible to make any fibre-based or cellulose-based product, from dresses to houses and plastics. Every part of the plant is usable, making hemp the most versatile and promising crop for the future.
H E M P C R E T E
Environmentally friendly with a quick growing cycle, hemp could become a cost-effective alternative to traditional insulation materials. When mixed with lime and water, hemp can be transformed into an incredibly strong material ideal for construction. Currently it is marketed under names like Hempcrete, Canobiote, Canosmose, and Isochanvre.
- The typical compressive strength is around 1 MPa, around 1/20 that of residential grade concrete
- 165 kg of carbon can be absorbed and locked up by 1 m3 of hempcrete wall during manufacture
- The material is considered to be carbon negative, meaning its construction consumes more carbon than it produces.
Hempcrete makes for an excellent insulator for the following reasons:
- It is a moisture regulator
- Requires minimal maintenance
- Lifetime is hundreds of years
- It lacks the brittleness of concrete and consequently does not need expansion joints
- Limecrete, Ltd. reports a fire resistance rating of 1 hour per British/EU standards.
- It does not attract pests or mould
- Has good acoustics
- It is a low density material and resistant to crack under movement thus making it highly suitable for use in earthquake-prone areas.
C A S E S T U D I E S
Hempcrete has been used in France since the early 1990’s to construct non-weight bearing insulating infill walls. France continues to be an avid user of hempcrete; it is growing in popularity annually. In 2010 the first modern hemp house was built in the U.S., Asheville, NC, for the then mayor. Building the 3,400-sq.-ft. contemporary-style showpiece cost $133 per sq. ft. Today, however, it can be found in hundreds of homes and commercial buildings in Canada and Europe, including an eco-house built by Prince Charles.
A catalyst that may spark growth in hemp home building is the Industrial Hemp Farming Act of 2018. The bill will remove industrial hemp from Schedule I of the Controlled Substances Act, allowing it to be regulated as an agricultural crop.
Currently hempcrete is a more expensive alternative to traditional building methods however as it becomes more easily available, the prices will decrease. Further, its green credentials make it preferable building material for the environmentally conscious. We are certainly looking forward to hempcrete becoming the new ‘tradtional’ building material. And if you don’t believe us, listen to Kevin.