Getting the basics right - The Hempcrete Topic: Designing and Building with Hemp-lime - page 98

Freshly mixed hempcrete should not be too wet. The method of testing for the
correct water content is discussed in Chapter 15 .
Once the wet hempcrete is mixed, it is placed into temporary shuttering, which creates the
shape of the finished wall like a mould. As each 'lift' is cast and takes its initial set, the
shuttering is removed and moved up the wall to create the next lift, until the top of the
wall is reached. The distinction between 'initial set' and 'drying time' is an important one.
Various types of hempcrete binder are available, but each specifies a short period of time
(usually overnight) after which the binder has set sufficiently that the cast hempcrete can
support its own weight. The shuttering is then removed to allow the drying to start. The
'drying time' refers to the time taken for any excess water introduced during mixing to dry
out of the wall. It normally takes several weeks until the wall is dry enough for finishes to
be applied (see Chapter 16, page 215 ) , so it is important not to increase this time through
the inadvertent addition of surplus water.
The phrase 'drying time' does not mean that the wall dries out completely. In common with
all natural materials, hempcrete always has some water within it. It dries until it reaches