Civil Engineering Reference
In-Depth Information
At the base of the walls, built off the foundations, is a plinth, usually of masonry construc-
tion, which serves as the 'good pair of boots' for the building. The plinth has a damp-proof
course (DPC) running along the top of it.
For more detail about the foundations and plinth see
Chapter 12
.
The structural frame
On top of the plinth and the DPC, the structural frame is constructed. The usual method
is to build a simple studwork frame consisting of a floor plate, studs and a wall plate of
untreated softwood timber. The cross-sectional dimensions of the wood required vary de-
pending on the size of the building, and of course for buildings of several storeys or which
include wide ceiling spans, a steel or glulam frame may be necessary. All fixings must be
alkali-resistant (stainless steel or, in the case of nails, hot-dip galvanized), as they need to
resist corrosion by the lime in the hempcrete (see Chapter 21, page
299
).
Further details on timber-frame design are provided in
Chapter 13
.
The frame is usually encased centrally within the cast hempcrete wall, but can be posi-
tioned flush with the surface of the hempcrete, either internally or externally, to make fix-
ing into the wall easier. For example, a wall that is to be clad with timber or masonry ex-
ternally would benefit from the frame being flush with the external face of the wall. Like-
wise, in a room where a lot of heavy-duty fixings will need to be made into the wall (e.g.
for hanging kitchen wall cupboards), then it is normal to have the frame flush with the in-
ternal face of the wall. Positioning the frame flush with either surface of the wall necessit-
ates some additions to the frame to ensure that the other two-thirds of the wall are properly
supported.
A note on fixing into hempcrete walls
Hempcrete, when properly applied, should not be tamped hard into the shuttering, but
instead spread evenly around in the void with a gloved hand (see Chapter 16, page
211
). This should result in a finished wall of low-density ('light and fluffy') hempcrete,
which has a high insulation value because of the air trapped in the wall. A low-density
hempcrete also dries more quickly.
Search WWH ::
Custom Search