An investigation of the thermal properties of hemp and clay monolithic walls

The monolithic walls of hemp-lime construction enclose and protect a structural timber
frame to provide a healthy, breathable building fabric that meets current UK building regulations. It
has been proposed that by using hemp as a building material it is possible to actually remove carbon
from the atmosphere. Whether or not ‗hemp-crete‘can be considered carbon sequestering, or even
neutral, depends largely on the binder. All the lime based binders have high embodied energy,
meaning they limit this possibility. Earth construction uses clay as the binder. Could clay substitute
for lime in hemp-crete? This experimental research focuses mainly on the thermal properties of
stabilised and unstabilised hemp-clay blocks which are tested using a transient heat-transfer probe
to measure thermal conductivity, volumetric heat capacity, and derive thermal diffusivity and
effusivity. Results are compared with industry-published data for hemp-lime (eg Lhoist, 2009) and
found to be similar. The results of the experiments and the literature review indicate that the use of
clay as an alternative binder has potential to reduce the environmental impact of the hemp-binder
method and facilitate the move towards developing a building material that can used for new build or
renovation works, that removes carbon from the atmosphere at this time of need.

Citation:
Busbridge, R. and Rhydwen, R. (2010) ‘An investigation of the thermal properties of hemp and clay monolithic walls.’, Proceedings of Advances in Computing and Technology, (AC&T) The School of Computing and Technology 5th Annual Conference, University of East London, pp.163-170..