Civil Engineering Reference
In-Depth Information
extinguisher next to them at all times. A tradesperson deserves some space and privacy in
which to do their work, however this is one occasion that I check up on them. If they are
doing work that has a fire risk without the fire extinguisher close at hand, I politely bring
it to them.
Installation of toilet cisterns
When investigating toilet pans and cisterns for straw bale construction the method of
installation of the cistern is the primary issue. Toilet pans have either an 'S' trap or a 'P'
trap. This refers to the shape of the discharge pipe from the toilet pan. The 'S' trap forms
an S from the toilet bowl thereby allowing the waste to travel vertically through the floor
of the building. The 'P' trap obviously has a P shape from the toilet bowel and allows the
waste to travel horizontally through the wall of the building. Wherever possible I would
suggest that you use an 'S' trap toilet pan, as this negates the issues associated with pipes
penetrating straw bale walls.
There are two basic styles of toilet pans and cisterns, the split system and the coupled
system. The most common and cheaper range of toilet pan and cistern is the split system.
These rely on the wall behind the toilet to support the cistern. You will see this type of
unit in most of the project homes or spec homes. The early versions of this type of cistern
had the pipe between the cistern and the toilet pan exposed, however, most these days
have a shroud covering the pipe, filling in the space between the pan and the cistern.
Installation cisterns that are screwed to the wall
If you are going to use this type of toilet pan and cistern it will be necessary for you to
provide timber for the cistern to be screwed into. The timber is normally set at 750 mm
from the floor, however the specific details for your unit will be on the installation
instructions. If the wall behind the toilet is a straw bale wall you will need to provide
timber for this fixing that is supported both vertically and horizontally. If there are
timber walls on either side of the toilet you can simply fit a piece of timber, ideally
140 × 45 between the two walls. You will not want this timber to be exposed once the
render is completed, so you will need to trim back the bales where the timber is to be
fixed so that the face of the timber is level with the face of the bales once it is fitted.
When straw bale walls are on either side of the toilet fit two legs to the cross rail so
that the weight of the cistern with its water is transferred to the floor. These too will
need to be set back into the wall. In this application it will be necessary for the top rail
to be fixed back to the wall to prevent the cistern moving forward when full of water.
This can be achieved by fixing wire netting over the fixing rail and extending
approximately 300 mm out each side of the rail onto the straw bale wall. The wire is then
stitched back to the wall and the render applied over the wire and the fixing rail. In this
method, the strength of the render to the wall is relied on to hold the cistern fixing rail
in place.
Another, and probably easier, method would be to use bale twine to tie the fixing rail
back to the bales. At each end of the cistern fixing rail, use your single bale needle to
thread bale twine through the straw bale wall behind the cistern, one above and one
