The hempcrete wall: an overview - The Hempcrete Topic: Designing and Building with Hemp-lime - page 217

Downpipe fixed into hempcrete with wooden wedges.
Where the timber frame is buried centrally in the wall, it is well protected, by the vapour-
permeable nature of the hempcrete, from moisture being held against it. Furthermore, the
lime in the binder not only protects against rot but also acts as a barrier to insect infestation
and as an anti-fungal agent. It is therefore acceptable to use untreated softwood for parts
of the frame that are encased in the wall (see page 134 ) .
Where the frame is flush with the external face to assist with tying cladding to the wall,
this part of the frame needs extra protection from water ingress. For details, see Chapters
13 and 18 . Where the frame is flush with the internal face, we have always used untreated
wood, but this will be a decision for you and for your building control inspector. An in-
ternally exposed frame is obviously less vulnerable to damp ingress, but depending on the
types of insect prevalent in your area, you might still have to consider treated wood or an