Foundations and plinth - The Hempcrete Topic: Designing and Building with Hemp-lime - page 238

nificant reduction in both the amount of earth to be excavated and the amount of concrete
used. Remember that engineers and building control inspectors will usually be unfamiliar
with the properties of hempcrete, so as a self-builder, or contractor, you may have to take
responsibility for ensuring that an alternative foundation is considered at the design stage,
and provide the necessary information to support this.
This hempcrete extension was built on a raft foundation (see step-by-step photos on page 150 ).
Foundations without concrete
As noted, the several tonnes of concrete used in a typical foundation make a significant
contribution to the overall carbon footprint of the building. For those wishing to construct
strip foundations without concrete, either to save money or reduce the embodied energy
of the finished building, the relatively light weight of hempcrete works in your favour,
as this means it is much more feasible to use non-concrete foundations. These could be
made from, for example, rock-filled gabions (heavy-duty wire mesh containers, as pic-
tured below right), a trench filled with compacted crushed limestone, or a trench filled with
limecrete. The use of free-draining foundations such as crushed limestone or rock-filled