Hempcrete: The Green Movement returns to its Roots

Smoking a rope made of modern, industrial hemp might cause a headache, but not much else. Why not build houses with it instead? As the Green Movement invents itself, builders are returning to old ideas. Both thick, earthen walls and building underground to reduce heating and cooling expense are old hat these days, but building the traditional, European-style village home requires something different.

Hempcrete built House

Three times more durable than concrete

Some builders have found their way back to hemp, a fast-growing, highly sustainable plant that produces those famously long, tough fibres. Not to be confused with the pot smoker’s favorite marijuana, which is grown from cannabis seeds. Mixed with a lime-based binder, hemp makes durable, prefabricated walls with up to three times the earthquake resistance of traditional concrete. Better yet, hemp delivers a double whammy. The addition of hemp insulation provides a high thermal inertia that reduces the energy required for heating and cooling. A hempcrete wall delivers a remarkable R-factor of 2.4 per inch before insulation. That’s more than R-28 for a standard 12-inch wall.

While durability and insulation are the big two, hemp lends itself to greater versatility than just walls and insulation. Roofing and flooring both enter the product mix as well. Add woven hemp products and a modern home, its floor, window, and wall treatments, as well as, the occupants’ clothes can all be made of a product with a negative carbon footprint. Hemp removes and sequesters as much atmospheric carbon as naturally regenerating forests, while producing about 4.1 times as much usable fibre and pulp.

Hempcrete built House - Inner wall

Dismissing chemical fertilizers, pesticides & weed killers

Perhaps more importantly, hemp farming doesn’t require chemical fertilizers, pesticides, or weed killers. Taken together these factors rank hemp among the most sustainable options available for modern home construction.

“Hembuild ticks all of the boxes when it comes to delivering sustainable properties, and the system is ideally suitable for what are two totally different styled houses but which fulfil the requirements of a scheme where the use of natural materials and environmental sustainability are the order of the day.” - Peter Smith of Roderick James, Architects in Scotland

Hempcrete has already found a home-building niche in the US, Canada, and Scotland. The US and Canada are currently still the biggest importer and exporter of hemp-based building materials, respectively. Hemp’s application in traditional home building gives particularly good news for anyone not quite ready to live like a hobbit, though hemp lends greater comfort and beauty to hobbit-holes, too. Hemp is an idea whose time has come, again.

Hempcrete built House - Kitchen

(thanks to Huffingtonpost.com for the images)