While hemp has been used in construction in Europe more than 30 years, the United States, since the inception of the 2018 Farm Bill, is taking baby steps toward implementing hempcrete and hemp insulation in standard building practices.
While very little testing has been conducted in the U.S., the practicable applications and studies out of Europe tell us that this is a cost-comparable and substantially more environmentally sound way to approach both new construction and retrofitting.
We’ve touched on hempcrete in past blogs, so today we’ll explore hemp insulation, one of the most popular ways the plant is used. Hemp has a low U-value, which is a measurement of the amount of heat that passes through a material. A low U-value indicates a material is an efficient
Since it’s derived from a fast-producing resource that while growing uses great amounts of CO2, hemp, in addition to being environmentally friendly, brings with it many other benefits when used as insulation.
Hemp insulation is 100 percent recyclable and unlike other materials, won’t cause irritation or damage to skin and lungs. Hemp naturally resists mold and bacterial growth, and since it’s core is cellulose, provides R-values comparable to other insulating materials providing great thermal and acoustic insulation and is processed in a manner that requires little energy leaving a relatively
small environmental footprint.
Hemp insulation is an eco-friendly composite material containing up to 92 percent hemp with the balance being polyester fibers held together with non- toxic binding agents. Even the additives used to make hemp insulation fireproof are non-toxic making the end product safe for all applications and emitting no odor or fumes.
Cost is slightly more expensive than other insulation, ranging anywhere from about $1.25 to just over $3 per square foot, depending on the size of the batts you intend to purchase.Typically, hemp insulation comes in 31/2-inch (R-15), 51/2-inch (R-15) and 8-inch (R-38) thick batts to accommodate both 2 x 4 and 2 x 6 construction.To obtain an R-50 value, insulation must be installed 11 1/2-inches thick. Professional installation is recommended.
The one drawback is that moisture can compromise hemp insulation. Therefore, it isn’t recommended for use in areas susceptible to retaining or gathering moisture, such as in basements.Installing vapor barriers in conjunction with hemp insulation can help mitigate any moisture-related concerns.
Whether undertaking a new construction project or retrofitting an existing structure, hemp insulation is now available as an alternative to other products. It may be a bit more difficult to find, but with a little research, you’ll be able to find retailers that can work with you to meet your hemp insulation needs.