From the Archive: 02-11-2010
The House that Hemp Built – The Concept
Hemp is one of the most versatile natural resources know to man. The hemp stalk produces long strong fibre around a high cellulose stalk.
As a crop it grows up to 4 metres high in 4 months with little input and can yield more than 20 tons of dry matter per hectare.
The hemp fibre is hollow and is prized for its strength and durability. It has good insulating properties and is used to create insulation products in mats and rolls. We are using 2 densities, 45kg/m3 and 25kg/m3 in the walls and floors of the hemp house.
The hurd, or woody stalk, that remains once the fibre has been removed from the hemp plant is porous and absorbent. When it is mixed with a lime based binder the calcium in the lime and the carbon in the hemp bond to form calcium carbonate which results in a light and strong “hempcrete”.
Hempcrete houses are breathable and healthy and save on energy needed to heat and cool them.
The hurd can also be compressed into a strong, light particle board that is tree free and has better insulating properties than wood products.
These products are used around a wooden frame to form walls which are breathable, durable, sustainable and carbon-neutral or better.
When we grow hemp in South Africa, we will be able to build around 100m2 of house for each hectare grown, as well as provide many jobs on the farms and in the factories necessary to support this industry.
Hemp farming and building will absorb a huge amount of carbon as the hemp grows so fast. This carbon is then locked into the walls, replacing the extremely carbon intensive brick and cement method of building.
For a good introductory video, watch this video from BBC’s Countryfile:
Why Modular Building?
Erwin van der Weerd at Perfect Places has developed a patented system for creating modular houses that are strong, versatile and very well insulated.
The concept revolves around pre-fabricated corner pieces and t-sections to which the wall panels connect, always on a straight line so that the joins can be concealed and insulated easily.
In South Africa this building method makes sense as it enables us to build anywhere while controlling the quality and workmanship in the factory while using semi-skilled labour on site to erect the building in a much shorter time than regular building takes.
It saves on security, wastage, site disruption, time and can be adapted to suit any design.
Hemp Modular Building, the perfect combination:
We believe that this method of building can really excel , especially once we can grow and source the hemp products locally.
With this method we are able to offer alternatives for affordable housing all the way through to state of the art Eco-housing.
We can help people overcome their apprehension of using an unknown material by providing them with the prefabricated frame around which to use the hemp materials.
It also enables us to build hemp houses all around our country or even the continent as the frame will come flat packed and construction is simple without the need for heavy machinery.
Hemp houses are the sustainable future.