Greener Than Green: Hempcrete

Texas may not usually be the state that immediately springs to mind when the words “bold innovation” appear in the same sentence, but The Woodlands, Texas, a community near Houston, is the site of America’s first hempcrete building. T. L. Hamilton tells us about it in the Montgomery Courier, while interviewing builder Gail Moran of Old World Exteriors. Moran told the reporter,

We’re cycling back to that traditional look and feel because it works better in some cases than the newer technology…I am so desperately wanting to make a difference in the way we currently build. I would like to see more people use natural products. I think they’re better for us and they look better.

How to build green is a topic on everyone’s mind these days, and hempcrete fulfills the requirements of being made from natural materials, being non-toxic, and providing energy efficiency. Formed into foot-thick walls on a wooden frame, the material eliminates the need for both insulation and sheet rock. Such walls are “breathable” and have a pleasant, natural appearance, as well as the ability to alleviate noise pollution from the outer world.

Skipping over to NaturalEnvironment.com, we learn that sustainable housing and hemp products go together like sunshine and picnics. It’s being used for fiberboard, mortar, stucco, insulation, fencing, pipe, and other housing-related applications, all over the world. Hemcrete, Isochanvre, Canobiote, and Canosmose are some of the trade names under which these products are marketed.

Hempcrete, which can be used in the same way as concrete, is made by mixing hemp, lime, sand, plaster and cement. It is mixed on site and sprayed onto the frame. Aside from doing away with the need for insulation, the material is waterproof, fireproof, and resistant to weather, rodents, and rot. It is said to be seven times stronger than concrete, as well as being more elastic, thus less prone to crack, and half the weight of concrete. Rather then emitting carbon dioxide, the construction of a hempcrete building can remove carbon dioxide from the air and trap it.

From another eco-friendly source, we learn that the growing of hemp yields four times as much material as the equivalent amount of land planted in trees, and can be harvested yearly rather than every 20 years. It grows well in many different climates, and its deep root system helps to prevent soil erosion. There is no need for herbicides, and very little call for pesticides in its growing; and since the ever-shedding leaves add to the soil, the land is left in better shape than before the crop was planted, and can be immediately used again the following year without needing to rest.

So, Gail Moran has achieved the distinction, with her small pottery studio/chapel, of being the first builder in the United States to use a material that humankind has depended on for centuries. Unfortunately for America’s farmers, builders, and environmentally-concerned citizens, hemp may not be grown in the United States and must be imported from more advanced countries.

SOURCE: ” Building green: Local company using hemp concrete ” 05/24/08
photo courtesy of psd, used under this Creative Commons license