Dry stone causeways
Practical Action
Now measure seven metres from each peg. Either use a tape measure, or place one foot
directly in front of the other (heel touching toe) until 21 footsteps have been taken. Drive in
the remaining two pegs, and again attach a string. Now the two strings must also be checked
for being level with each other. Using one of the above methods, compare the string levels at
each end.
This procedure is simpler than it may sound, and it is very important. Take your time and
double check every action. It is much better to spend an extra ten or twenty minutes at this
stage than have a causeway that is not built correctly. Once the strings are satisfactorily
attached, the building can begin.
Building
There should be a good supply of large
boulders dumped close to the strings,
and these are now manoeuvred into
place along the line of the string.
Starting at one end, position a boulder
so that the top of the boulder is the
same height as the string, and as close
to it as possible without actually
touching. Most boulders are unevenly
Figure 3: Uneven boulders need to be pinned
shaped, and will need to be 'pinned'
with wedges of stone driven beneath
them. These wedges need to be tapered or pointed; square or round stone are not good
because they can fall out far too easily (see Figure 3).
Once the first boulder is in position and securely pinned, place another beside it in exactly
the same way. There is a very important rule to be followed at this point, and that is that
every boulder must touch the one beside it. Never leave gaps between the boulders. When the
second boulder has been positioned and pinned, push more pins into any space left between
them.
Continue laying boulders
along the string, leaving a gap
of one to one-and-a-half
metres in the middle for the
drain sections. Boulders must
then be laid along the second
string in exactly the same
way, again leaving a gap in
the middle for the drain.
Once the two lines of boulders
are in place, remove the
Figure 4: Putting in the drain sections
string. Now take the drain
sections and, starting from
one side, place them one after the other across the
causeway. The first one must stick out a few
centimetres, and each one after that must overlap a
little - say by 20 centimetres or so. This locks them
together. They must also be level, and so it may be
necessary to pickaxe any obstructions out of the way
(see Figure 4).
Once the drain is in, finish the layer by placing
boulders to lock the drain in place. Now the centre of
the causeway is filled up with stone. In fact, the
centre can be filled as the boulders are laid if you
wish, providing the stone coming in does not interfere
Figure 5: Breaking the joints
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