Civil Engineering Reference
In-Depth Information
a crow bar. Obviously, when fitting concrete stumps you will not ram the soil around the
stump at the time of installation.
Stumps must be vertical
The stumps need to be accurately positioned both laterally and vertically. Each stump
must be vertical, as this will allow the load of the house above to be transferred directly to
the foundation below without adding stress to the stump. You use the string lines fitted to
the nails in the hurdles that represent the outer perimeter of the house as your guide. In
many instances the one string line will be used to set both the height and lateral position
of the stump, if however the string line does not reflect the required position for the
height of the stump, then a second string line should be installed for this (see Figure 3.3).
Stumps fitted between strip footings
When fitting stumps between strip footings, pull the string line taught over the footings
to establish the height of the stumps. If you do not have the hurdles or a strip footing as a
guide for the height of the stumps, set the height of the four corner stumps with a water
level, dumpy level or laser level. For details on a water level refer to page 46. Once the
corner stumps are secured, including time for concrete to set, draw a string line over the
top outer edge of the two outer stumps (see Figure 3.3). Do this across the ends of the
rows of stumps, as then once these stumps are set you will use the second batch of stumps
as a guide for installing the rows of stumps. It is often difficult to get the string line to stay
on the top of the stump at its outer corner. Position the string line on top of the stump
and then place a half brick on the top of the stump, thereby holding the string line in
position on the outer corner of the top of the stump. Use a wire cut brick rather than a
solid brick, as they have holes in them that can be threaded over the pin of the concrete
stump (see Figure 3.3).
Figure 3.3
String lines for the installation of concrete stumps
Cutting timber stumps to the correct height
As previously detailed, timber stumps are to be cut approximately 50 mm longer than
required to allow for accurate cutting to length once all stumps are installed. To cut the
