Mana Hempcrete walls

A lot of people ask us why we decided on hempcrete as a wall structure. There are many logical reasons for our choice, such as its insulation qualities, the fact that it is a very natural product that fits with our philosophy that the house should be largely compostable, it’s breathability and it’s ability to regulate humidity. However the house was originally designed as a straw bale house. The reason was simply that we went to visit East Yorkshire Hemp and they showed us around their house extension which was made with hempcrete walls and it felt like coming home on a very spiritual level. The air was pure and fresh, the humidity was perfect and the sound quality was superb and we just had a very instant feeling that our house would be built with hempcrete.

Hemp is a very carbon negative material in that it locks up more carbon in the growing of the plant and the curing of the hempcrete than is used to produce it, and it continues to absorb carbon throughout it’s life time. Farmers can grow two crops per season and it does not need fertiliser and pesticide.

When building a house simplicity is the key and we love the fact that the walls consist of just three elements; hempcrete, clay plaster and lime render. No membrane is required and the whole wall can breath and absorb and release humidity to provide a healthy environment to live in. These qualities also mean that there is minimal risk of mould growing. It has thermal mass which helps to keep a consistent temperature inside the house.

Our walls are 360mm thick and were cast by Hempcrete Cymru and a team of volunteers over a period of 13 days. It was great fun and things moved very quickly with each lift taking just over a day and then the fiddly bits when we reached the roof line and had to tease material into tight spaces. It cures in a matter of 2 to 4 weeks and this summer it was rock hard a just a few days.