So, why use hemp?

The strong cellulose of the hemp stalk makes it highly durable and when bound in lime, it is capable of going from wet to dry almost indefinitely without degrading. A hempcrete wall has a good ability to absorb and release moisture in response to the internal environment, and has a lot of air trapped within both the cell structure of the shiv and the matrix of the hempcrete itself.  Combined with the dense mass of the lime binder, this means the wall has both insulation and a good amount of thermal mass, in addition to being vapour-open and hygroscopic; meaning it offers excellent thermal and humidity regulation in the internal space.

In addition to its technical performance, storing hemp shiv in the wall has huge environmental benefits. The main environmental benefit is the very high level of atmospheric carbon that gets sequestered within the material. The reason the hemp plant absorbs so much carbon dioxide is because it is a tall, fast-growing plant which needs to create a hard woody stem to support itself at its full height. It grows up to 4 ½ metres in 4-5 months in the UK climate. The hemp plant is naturally pest-resistant and weed-suppressant, eliminating the need for chemical fertilisers and insecticides, and is useful as a break crop, naturally clearing the land of pests. It requires very little fertiliser, and is deep rooting; returning key nutrients to the soil and improving the condition of our over-compacted, depleted farmland by breaking up and aerating the soil to a significant depth.