Building with stone and earth: Part 1
Practical Action
Now mix up some mud mortar (termite soil and water); it should be thick, but wet (like cement
mortar). Place some on the foundation layer, the same width as your measuring stick. Do not put
too much along the foundation at once, or it will dry before the stones are laid. Place two or
three stones on the mortar one after the other, so that their outer edge is exactly in line with the
knot you tied in the string.
Then take your measuring stick, line up one side of the stones you have just laid, and lay several
more opposite them. The outer faces of these stones should exactly line up with the other end of
the stick.
Once you have laid stones on the inside and outside, you must fill the middle. First put a layer of
smaller stones into the centre. If these do not fill up the middle completely, add a thin layer of
mud and then some more small stones. The mud should touch all the stones in the wall.
There are two very important rules that you must keep in mind all the time when laying the
stones. First, always have the longest side of the stone running into the wall, not along it (see
drawing above). The more it goes into the centre of the wall, the stronger the wall will be. Next,
never fill the centre of the wall with just mud. It can be very tempting just to heap mud into the
middle to level up, but this is very bad practice and will weaken the wall.
There should only be enough mud to bind the stones together.
The same goes for the mud between the layers of outer, or face
stone. Put them onto just enough mud that the stone sits
securely.
Keep the stones level. A very common fault is to lay a stone so
that the top surface slopes steeply outwards. Think what will
happen when you have to put a stone on top of this; it will slide
out.
You may have to support the stone to make it level; use stone
wedges, not just mud.
Figure 6: Try and find
longer stones for the
doorway, one laid across
and two running back
into the wall
Always, always check each stone's position using the knot or
measuring stick. It is the only way to keep the wall straight and
true, and the same thickness all the way up. Stand back and look
at what you have done from time to time, to see if any mistakes
have crept in. Finally, try to keep mud off the outer faces of the
stones; it looks much better.
Carry on until you reach the door poles. Here, it is best if you
use a stone at least as long as the measuring stick, so that one
stone runs right across the wall. If that is not possible, find two
stones of equal size that together are the same width as your
wall.
The best way to build at the door
poles is shown in the diagram at
left.
Running the stones first across,
and then back into the wall is
best, otherwise simply use stones
that are as square as you can
find, trying to break the joints.
Remember the mud will hold the
stones strongly.
With the first layer completed,
you can begin another, working in
exactly the same way. The only
Figure 7: Break the joints, so you do not get lines of
stones sitting on one another.
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