Getting the basics right - The Hempcrete Topic: Designing and Building with Hemp-lime - page 99

a natural equilibrium or 'resting moisture content', which fluctuates slightly depending on
environmental conditions, because of the vapour-permeable and hygroscopic properties of
the wall.
The other important aspect of application technique is the placing of the hempcrete itself.
(Hempcrete is 'placed' rather than 'poured'.) The wet mix needs to be placed evenly and
consistently within the void created by the shuttering. In particular, it is important to avoid
over-compaction of the cast material. Over-compacting reduces the insulation performance
of the finished material and also increases costs, as more hempcrete is needed to fill the
void. In addition, the consolidation of the external faces of the cast hempcrete needs to be
judged carefully, as this can also have implications for drying time, as well as the cost of
finishes (less well-consolidated surfaces may allow faster drying of the wall, but require a
greater thickness of plaster or render).
The above factors mean that, perhaps more so than with other natural building materials,
variations in the technique or skill of the builder can have a significant effect on the pro-
gress of the build, and on the performance of the finished product.
The issues described above are discussed in more detail in Chapters 15 and 16 .
The workforce
With the importance of technique in mind, it is worth turning our attention briefly to the
people who will be doing the building.