Hempcrete walls for house extension construction.

This system exploits a very old building material that was ditched for the stronger cement based products just after the war. Lime has an established track record within the construction industry.

It is now making a comeback with the explosion of the conservation movement and educational training.

Lime as a mortar when mixed with hemp fibres can form a new eco-friendly building material that is slowly gaining support.

However, whether it ever leaves the eco warriors farm lodgings into mass house building within the next 20 years remains to be seen.

Hemp is used as a reinforcing fabric within the lime just as steel would be used in concrete but in a lower level of stress and load applications. This slurry can be hand applied or mechanically sprayed. It is not strong enough to be used as a load bearing material in its own right as that on concrete but for surface applied interior & external finishes it is a very viable rendering product.

They say that expansion joists can be eliminated due to the way lime cures with thousands of fine cracks as it shrinks rather than large one off cracks applicable to other cement based products and materials.