The structural frame - The Hempcrete Topic: Designing and Building with Hemp-lime - page 257

makes them lighter and easier to handle, and also means that timber of smaller sections is
used. This is more sustainable, since it can be harvested from younger trees.
There are three main options for engineered joists:
Glulam beams , which are constructed from glued softwood timbers.
Trussed joists , constructed from two small-section timbers joined with a metal web.
Timber I-joists , constructed from two small-section timbers joined with OSB.
The manufacturers and suppliers of these products are very helpful, and given basic draw-
ings they will be able to specify joists for a given situation.
For a more in-depth discussion of frame design, see Chapter 22 .
Position of the frame within a hempcrete wall
The stud frame can be positioned at different places within the hempcrete wall. Often the
position varies in different walls of the building.
Central frame
The default position for the frame is to have it encased in the centre of the hempcrete wall,
and this is preferred, as here the structural timbers are well protected from moisture and
insect attack. Another advantage is that the frame provides a more stable structural support
to the hempcrete when placed centrally, since the weight of the hempcrete is evenly distrib-
uted around it. This type of frame requires the most work to erect the temporary shuttering,
but with careful planning this can be well streamlined.