4. Dig a circular pit; 220 cm diameter and at least 50 cm deep.
Figure 4.2 Digging the foundation
5. Cover the bottom of the pit with a layer of sand. This layer should be at least 5 cm thick. Lay the
polythene sheet over the sand in the bottom of the pit covering the base and the sides of the pit, and
overlap at the top by at least 10 cm. This is the damp-proofing. Put another thick layer of sand in the
bottom of the pit over the polythene sheet to protect it from sharp stones.
Figure 4.3 Lining the foundation
6. Fill the pit with broken stones. These
should be the hard type that do not soak
up water. Put a final layer of small stones,
chippings or bits of broken pottery and
flatten it with a rammer or piece of wood.
Spread a thin layer ofmurram over the
stones and ram it to form a solid surface.
Ensure that the foundation is level using a
spirit level if you have one. Where it is not
level, use more murram to make it level.
Figure 4.4 Levelling the foundation
11