Hempcrete: The Insulation Material with the lowest Carbon Footprint Available

If I told you about a wall infill material that has a high R-Value, has unique thermal mass properties that are hard to beat, can filter the air, is VOC free, is ideal for people with chemical sensitivities, self regulates humidity/condensation, is fire/mold/insect resistant, can potentially save up to 60% of your heating and cooling bill… oh, and it is CARBON NEGATIVE, would you believe me? 

Hempcrete is beautifully efficient because of the simplicity of the product. Hemp Hurds, a Lime Binder and Water. That’s all. The ingredients are simple, and it is simple to install. This leads to minimal points of potential failure. The transition areas (floor to wall, wall to ceiling, and around windows and doors) that are normally so difficult to insulate in a house are done so with ease because it is cast in place. 

Hempcrete is installed by placing shutters -similar to concrete forms- on either side of the wall, then compacting the material in six-inch lifts. The shutters can be removed as soon as the top is reached. Typically, they are done in 2-3 foot high sections and the wall is completed by slipping the shutters up as you go. The structural members of the building are in the interior of the wall so there is no thermal bridging that occurs in other insulation methods. Hempcrete takes the place of not only the insulation, but also the exterior sheathing, weather proofing (Tyvek or tarpaper), drywall, lots of caulking and much more.

Once a moisture content of 15%-20% is reached, the interior side of the wall can be coated with a breathable lime plaster. On the outside, a breathable lime render (stucco) can be applied directly over the hempcrete without the need for lath or weather proofing membranes of any kind. The use of breathable materials to coat, or top, the hempcrete is imperative to the functionality of the product. It will in fact aid the wall system to self-regulate the interior humidity/condensation levels by drawing the moisture out of the air. This results in a more comfortable interior environment.



A bast fiber plant, Industrial Hemp is an agricultural cash crop that is used in a variety of industries. The oils pressed out of the seeds for the food industry, the fibers for the textile and paper industry and the inner woody core (hurd) is used in the building material industry (think wood chips, particle board, and HEMPCRETE). Unlike Hemp’s cousin, Marijuana, the narcotic chemical THC is less than 0.3% in industrial hemp. This makes it not possible to catch a buzz from smoking it. As of now, it is legal to buy, sell and use industrial hemp, we just cannot grow it in the United States yet…yet. There are currently over 30 states that have begun the process of creating pilot programs where they are researching the economic value and stimulus to the job force that legalizing growing and processing industrial hemp could provide. Some states are further along than others and production, processing and use is already underway with legally grown USA Industrial Hemp!

Houses have been built with hempcrete for decades in Europe and the trend is already setting its roots down in the United States. From tiny houses to industrial warehouses, the effectiveness of hempcrete is appealing to all.

If you have a question or need assistance with your project, contact us at: www.LimeWorks.us