Being Sensible…: Hempcrete (just the best stuff ever)

I’ve mentioned in at least one past post that industrial hemp has a ridiculous amount of uses.  This week, my topic will regard one of these many topics that I find particularly notable – and fascinating: Hempcrete.

                If you can recognize that the word Hempcrete is mysteriously similar to a certain building material, then you are on the right track.  Hempcrete is indeed an alternative to concrete and, as per the trend with hemp compared to more conventional and less illegal materials, is superior in a number of ways.  But first, a brief explanation of what exactly Hempcrete is will be in order.

When hemp is made into a pulp for paper or textile products, there is a particular part of the plant that ends up as byproduct.  This byproduct, called “hurds” or “shivs,” is comprised of the woody/strawlike interior to the hemp stems.  Dried, hurds are mixed with lime as a binding agent, and a small amount of water is added to bring the mixture to the consistency of “apple crisp.”

In order to turn this raw material into the walls for a “hemp house,” the Hempcrete is packed lightly into plastic or wooden molds, and then left to harden for a few days.  This is continued in a block-like fashion until the walls are completely constructed.  The Hempcrete is said to continue hardening indefinitely as the lime in the mix draws in CO₂ (which also means a continued negative carbon footprint).  Hempcrete walls are most often framed with wood.

Other than being “carbon negative,” in its construction and growing more solid as a structure as countless years pass, there are of course other advantages to building with Hempcrete.  The material allows for excellent insulation (meaning little to no heating energy costs in many regions and excellent noise cancellation) while simultaneous being breathable to seasonal moisture.  This means that, instead of being susceptible to cracking, mold, or other water-related damages associated with high humidity, the Hempcrete walls will absorb and release such ambient moisture with no complications.  Finally it is worth noting that Hempcrete is extremely lightweight compared to alternatives, with superior hardness and resiliency.

Using organic waste to create a superior building material? I’m sold.  Now to work up the funds and – oh yeah – START GROWING HEMP IN THE UNITED STATES.

Here’s a more recent update in the field of Hempcrete construction, Hempcrete spraying: http://www.ecobuildingmag.com/newsitem.asp?newsID=419