Key concepts in sustainable building - The Hempcrete Topic: Designing and Building with Hemp-lime - page 87

in which heat is lost quickly and the indoor air frequently has to be brought back up to a
comfortable temperature from a low starting point.
For information on research into hempcrete's thermal performance in a building, see
Chapter 7 .
Thermal bridging
As described in Chapter 2 , cast-in-situ hempcrete is wet-mixed and then cast as a single
insulating mass, in a shape dictated by the construction of shuttering. It thereby forms a
continuous flow of material around the walls - and sometimes the floors, ceiling or roof -
of the building.
This feature of hempcrete as a building material, when cast in situ, allows for the easy
elimination of thermal bridging, or 'cold bridging'. This often occurs at points around the
structure of a building, where a material with higher thermal conductivity forms a connect-
ing passage across the insulating layer, from the outside air to the inside. Such 'bridges'
allow the escape of heat from the indoor environment through the 'tunnel' of the less in-
sulating material, and often result in localized cold spots where condensation can occur,
promoting mould growth.