Article by Zoë Biehl, Cannabis Tech
Concrete, steel, and wood pale in comparison as a sustainable building material to the plant known to grow like a weed — hemp.
With construction consuming a whopping 40% of the world’s global energy and resources, it is imperative that this industry moves towards more sustainable practices in the face of climate change’s many threats. This means moving away from building materials which are mined from the earth or harvested from rapidly depleting forests, and making the switch to renewable resources — and hemp is the perfect material for the job, in the form of a mixture known as hempcrete.
What is Hempcrete?
Hempcrete is a building composite similar to concrete, except it’s made by wet-mixing hemp hurds (woody fibers from the plant core) with a lime-based binder and water. This mixture can then be cast into molds or applied directly as a wet loose-fill material which hardens once dried, serving several construction and insulation purposes.
For instance, hempcrete may come in modular block form — similar to concrete masonry units — for building structures. It may also be used to form insulated walls, with the only other material being the wooden structural frame.
Moreover, hempcrete can be used in combination with other building materials to form both floors and roofs, providing an insulating layer. Astonishingly, hempcrete can even be used today for load-bearing walls. UK Hempcrete has a new system consisting of adapted hempcrete blocks and reinforced concrete.
Hempcrete is also an ideal building material to be used to restore or retrofit traditional or historic buildings. For example, hempcrete can replace or repair infill panels in timber frame buildings, be used to add insulation to solid walls in older buildings with poor insulation, or it can be applied to unevenly shaped walls to improve their appearance.
Hempcrete provides a wide range of benefits — commercially, structurally, and environmentally.
Benefits of Using Hempcrete
Hempcrete has numerous advantages as a building material. Hempcrete lacks the brittleness of regular concrete, removing the need for expansion joints typically required for absorbing vibration and temperature-induced expansion and contraction in structures. Easier to work with, hempcrete is also much more lightweight.
Unlike wood, hempcrete is naturally fire-resistant and pest-resistant. For example, it is virtually impossible for a hempcrete building to become infested with termites.
The material is also highly useful for structures in earthquake-prone areas, as hempcrete’s low density renders it resistant to cracking under movement.
Walls made from hempcrete are very breathable and allow moisture to pass through, which makes hempcrete highly resistant to mold. Moreover, it has low thermal conductivity and wind-resistant properties, making hempcrete an ideal insulator. Buildings made from hempcrete easily stay cool in the summer and warm in the winter — resulting in a perfect material for nearly any climate and leading to substantial energy savings.