Factoid #8 – Cannabis Concrete? The Next Generation Building Material
Did you know that Hemp can be made into mortar and brick to build homes? Today, more and more eco-friendly contractors are turning to this remarkable plant for more than just food and fabric.
Also referred to as hempcrete, limecrete, and hemplime is a bio-composite material the use of this ‘textile block’ is durable and has some superior insulation properties. It is just as easy to make as conventional concrete which bonds exceptionally well to lime, a key ingredient in cement. A basic hempcrete recipe consists of is 4-1-1 mixing ratio. Four parts industrial hemp hurd to one part lime-based binder, to one part water. Water is mixed with dried hemp hurd (the inner core of the hemp stalk) first so that it can reconstitute itself and adhere to the lime molecules. The mixture is then used to fill block and brick molds for drying. It can even be used as a stucco application. Setting and drying will fluctuate depending on the temperature and humidity of the day.
Hempcrete, if mixed properly, is mold resistant, pest resistant, and fire retardant with amazing R-Value. It is more flexible than concrete block and won’t crumble on impact which means it doesn’t need expansion joints. Nails can easily be driven into hempcrete brick with adhering sheathing or drywall. It is a perfect moisture regulator while absorbing CO2, retaining the carbon and releasing O2.
You can also use discarded and leftover hempcrete as a soil amendment.
Unfortunately, builders still need to import hemp hurd products from Canada and China.