Hemp Building Materials

Published in The Belize Ag Reporton August 20, 2017 in Issue 37
by Karin Westdyk


James Savage, a New York business analyst, was greatly disturbed after learning about mold problems making thousands of New Orleans homes uninhabitable after hurricane Katrina, and of the thousands killed in Haiti, crushed by their own homes during an earthquake. He searched for solutions and came up with a material that has been around for thousands of years and started a company to create building materials made from mold resistant, stronger-than-steel cannabis hemp.

The outer portion of the hemp stalk has a long history of use for producing paper, fabric, rope and sails (the word canvas comes from the word cannabis), but Savage discovered that hemp chips made from the woody interior of the cannabis plant combined with water and lime made a very strong rigid material that could be cast into walls, between or around structural supports. Hempcrete walls, when cured and finished, are airtight, yet flexible and breathable, and totally free of toxins and mold. These walls are also insect and fire resistant, and with a high R-value (measurement of insulating power), could eliminate the need for air conditioning in hot climates and greatly reduce heating costs in colder climates. Hemp is strong and vapor permeable, while impermeable to water. It has been projected that houses made from hempcrete could last for 700 years.

Hemp Plywood
Found to be one of the strongest natural fibers on earth, hemp is an extremely renewable, highly-sustainable carbon negative building material and is projected to even replace plywood for building. Trees take upwards of 10 years to grow and we are cutting down 3 to 6 billion trees every year for use in manufacturing. Hemp takes only 4 to 5 months to grow and one acre of hemp can produce as much fiber pulp as the 4 acres of trees, now used to produce the same amount of plywood. In addition, the quality of hemp fiber is far superior to that coming from trees. Fiberboard made from hemp tested at Washington State University demonstrated that it was indeed stronger than steel, could withstand extreme heat and force, as well as resist water.

Hemp Insulation
Hemp fiber batting insulation is made by bonding hemp fibers into sheets, shaped and cut into various sizes and then installed as semi-rigid batting between structural framing. Hemp “batt” insulation exhibits a higher insulation performance than traditionally used fiberglass as well as any other insulation materials.

Hemp Finishes and Stains
Hemp oil wood finishes and stains are excellent alternatives to synthetic petroleum-based polymer coatings. Produced from pressing the oil seed, they are easy to use, make a handsome finish, and are extremely durable. Tests have demonstrated that hemp finishes outperform high-grade commercial wood finishes in resistance and weathering, while containing very low levels of toxic volatile organic compounds making them safer to use.
Hemp Plaster

One of the main benefits of hemp plaster is that it is easy to apply more thickly and smoothly than conventional lime plasters. It is also well-suited for use in environmentally “green” buildings, as it can be applied directly to a variety of materials such as fiberboard, wood wool board, or straw bale construction. Hemp fibers added to the plaster not only improve the strength and flexibility of the wall, but also increase the insulation value.

Hemp can be used in making practically any building material. In addition to hempcrete, batting insulation, plywood, wood finishes and plaster, hemp can be made into roofing and flooring materials, caulking, paneling, reinforced concrete, spray-on insulation, concrete pipes, bricks, and biodegradable “tougher than steel” plastic composites.
In light of serious climate change predictions and a growing concern about the devastating effects of deforestation on the environment, it makes perfect sense that hemp be explored and developed as an agricultural crop to replace traditional building materials. Industrial hemp could be big business, not only for the building industry, energy industry (see August 2016 issue #33: Industrial Uses of Hemp), medical industry (see February 2017 issue #35: Growing Hemp for Medicine), and food industry (to be explored in our next issue) but for the farmers who grow it and who would also benefit from its use as a soil amendment (see November 2016 issue #34: (Industrial Hemp: Medicine for the Soil) and weed killer (see May 2017 issue #36: Industrial Hemp as Weed Killer).

As we make the positive essential shift to a future that embraces more sustainable agriculture practices, industrial hemp can lead the way — creating a win-win situation for the economy and the environment.