Hemp in construction - The Hempcrete Topic: Designing and Building with Hemp-lime - page 21

causing the binder to fail. The only way to avoid this is to compensate by adding a lot more
water, but this will significantly extend the drying time of the hempcrete. The presence of
excessive amounts of dust in hemp shiv for building is to be avoided at all costs.
Hemp should be stored dry, although it comes in plastic-wrapped bales, so there is a certain
tolerance of these being left outside on-site in the short term if suitable storage is not avail-
able. The shiv should go in the mixer as dry as possible, to avoid excess water entering
the mix, but if some areas of a bale do get wet it will not affect the quality of the finished
hempcrete. However, if the shiv has been subject to prolonged exposure to moisture and
starts to show signs of rotting (the colour changing to black), all black areas should be
scraped out and removed from the bale before adding it to the mix.
There is no need for any treatment of hemp shiv with fire retardants or preservatives as
long as it is being used with a lime-based binder for hempcrete. Once cast as hempcrete,
the lime in the binder acts to effectively inhibit insect attack and protect from dampness
and fire.