Performance of hempcrete in a building - The Hempcrete Topic: Designing and Building with Hemp-lime - page 130

carried out in 2012 by Patrick Daly, Paolo Ronchetti and Tom Woolley as part of the
Irish Environmental Protection Agency's STRIVE Programme 2007-2013: entitled Hemp
Lime Bio-composite as a Building Material in Irish Construction , it is published online.
This study provides an authoritative analysis of up-to-date evidence from a wide range of
sources on the performance of hempcrete, together with a discussion of whether hempcrete
will meet Building Regulations in the Republic of Ireland, and identifies necessary areas
for future research.
For a less up-to-date, but still very useful and accessible discussion of hempcrete, includ-
ing its performance in relation to UK Building Regulations and the wider industry context,
see Rachel Bevan and Tom Woolley's (2008) Hemp Lime Construction: A guide to build-
ing with hemp lime composites.
Since we are builders, not academics, the information presented in this chapter owes much
to the three publications cited above and is provided here as an overview of the properties
of hempcrete, rather than as a specific guide to what you should expect in your building.
For accurate information on the expected performance of specific hempcrete materials, it
is important that builders and/or their clients refer directly to the supplier or manufacturer
of those products.
Mechanical behaviour
Hempcrete is a composite material made from a porous plant aggregate (hemp shiv) and
one of a choice of binders, which set through differing degrees of hydraulic and carbonat-
ing action. The aspect of hempcrete that most differentiates it from conventional compos-
ite materials used in building, such as mineral concretes, is the extremely porous nature,
at a microscopic level, of the plant-based aggregate. This porosity gives the hemp shiv
particles a natural flexibility, and this, together with the macroscopic porosity created by
the arrangement of the particles of hemp in the cast material, results in many unique char-
acteristics - lightness, absorbent capacity, and acoustic and thermal properties - not shared
by mineral concretes, which usually contain hard, non-porous aggregates.