Civil Engineering Reference
In-Depth Information
appropriate hardwood. The timber may be covered with 10mm or more of lime plaster,
which itself gives a decent level of protection from insects for as long as it remains intact.
The frame design is a part of the process that is well worth spending time on, in order to
gain the maximum benefit from possible variations of design around the building. Frame
design needs to take all of the above factors into account, and the designer also needs to
think about the temporary shuttering system at the frame design stage, so that it is clear
how the two will interact. This aspect is often overlooked, perhaps because designers rarely
have direct experience of building with hempcrete.
Shuttering
Shuttering for hempcrete walls is either temporary, constructed on-site from a lightweight
reusable timber board (11mm OSB is usually the preferred choice), or permanent, con-
structed from any breathable carrier board that will take a lime or clay plaster over it, and
which will not laminate away from the surface of the hempcrete behind it (typically a wood
wool board).
Temporary shuttering is fixed to the frame using very long heavy-duty screws, and is held
at an exact distance off the frame by spacers (usually made from plastic waste pipe cut to
length). Permanent shuttering needs a frame detail which includes studs positioned on one
side of the wall, to which the shuttering board is fixed.
After the placed hempcrete has taken its initial set (usually overnight, but the time varies
according to the binder used), temporary shuttering is struck, and moved along or up the
wall to the next place it is needed. In this way the total shuttering board required on-site is
restricted to a little more than the amount needed to shutter up what you can fill in a day
Care must be taken to ensure that shuttering is true, plumb and square, so that the face of
the finished wall is straight and vertical.
For more detail about shuttering, see
Chapter 14
.
Search WWH ::
Custom Search