Restoration and retrofit - The Hempcrete Topic: Designing and Building with Hemp-lime - page 478

Hempcrete, lime render and limewash complement the
original materials and aesthetic of this building.
Casting hempcrete internally allows the retention of the original façade, but obviously in-
volves more disruption for the building's occupants. Depending on the exact requirements
and if the work is carried out carefully, it is possible to insulate internally with no more dis-
ruption than that encountered when replastering. Needless to say, spray application would
not be advisable in this context. In general, internal insulation is a much more sensible op-
tion when a complete refurbishment of an old property is being undertaken.
Internal insulation will always demand a balance to be found between the insulation
achieved and the amount of room space lost. Synthetic insulations perform better than
hempcrete at lower thicknesses, but are to be avoided in older buildings as they seal up the
breathable wall. The only other natural solid-wall insulation (unless you have the space for
straw bales!) is a wood-fibre board, but unless the wall is completely flat this will leave
voids behind it, and it may not stick very well (it's often glued in place with breathable
adhesives).