Performance of hempcrete in a building - The Hempcrete Topic: Designing and Building with Hemp-lime - page 128

relatively new, more research is needed for a full understanding of the way it be-
haves and which factors influence its performance. Each new hempcrete building
provides an opportunity for us to further develop and standardize good practice in
hempcrete construction, and to gather more evidence about how the material per-
forms.
Plant-based products in general are set to be a growth sector supporting a wide range of
technologies, as the world makes the transition into a low-carbon economy. Within this
context, the viability of hempcrete along with other bio-aggregate building materials is be-
ing studied in a number of research centres; notable examples are the University of Bath in
the UK and the Université de Rennes in France.
Much of the research to date has been undertaken, or funded, by the manufacturers of pro-
prietary products and has focused on proving the performance of their own products in
relation to regulatory regimes for building products, which vary slightly from country to
country. The comparison of data and research findings is complicated by the use of differ-
ent materials, and different techniques for their preparation and application across differ-
ent studies, as well as by differences in the particular focus and legislative context of the
research. Furthermore, there has been reluctance from some quarters to make proprietary
research available to a wider audience, and this creates an issue regarding the accessibility
of the knowledge base about hempcrete to the wider industry.
While France has begun to address regulatory standards in material parameters, such as
the characteristics of hemp shiv for building, there is not, at the time of writing, a set of
nationally or internationally agreed standards available to guide manufacturers or builders
in the UK. The lack of standardized procedures around hempcrete production and use in
the UK is challenging, not only for builders but also for those wishing to draw conclusions
from a wide and varied body of research.
It is worth stating at this point that a recurring theme in the research to date, as well as in
the experience of day-to-day practical use of hempcrete, is the degree to which the proper-
ties of the finished composite material vary according to three key factors, namely:
the individual characteristics of the component parts (the hemp shiv and the binder)
the exact formulation (or mix ratio) of the component parts and water
the technique used during the mixing and placing of the material.