Placing hempcrete - The Hempcrete Topic: Designing and Building with Hemp-lime - page 370

calibration of such a moisture meter for hempcrete would be a valuable focus for future
research.
Moisture reading for a pretty dry hempcrete wall.
The GE Sensing Protimeter shown in the photos opposite is particularly useful for hemp-
crete, having the option of longer sensing probes (bought separately) to extend the reach
of the testing inside the surface of the wall (to a maximum depth of 100mm). It gives read-
ings in WME (wood moisture equivalent), expressed as a percentage moisture content, and
readings are also shown with a coloured light following a 'traffic light' system: red (up to
90 per cent WME), to amber to green. Green values are less than 16 per cent WME, which
is the ideal moisture content for hempcrete. (While this may not show the exact percentage
moisture content for hempcrete, for the reason described above, it is a good starting point
from which to judge dryness - a skill that comes with experience.)
When taking a moisture reading, press the 100mm metal probes carefully into the wall to
avoid snapping them, as they are quite narrow and fragile. Once inserted to the desired
depth, leave the probes still for 5-10 seconds to allow the reading to 'settle'. Ensure that
many readings are taken around the building, at varying depths below the surface and at
different heights on the wall. Remember also to take several readings in each locality and
compare them, since hempcrete is not a homogeneous material, and with the probe tips in-
side the wall you are not able to see whether they are in contact with hemp or binder, or
sitting in an air pocket.