For small buildings, excavation is carried out manually by means of pick axes, crow bars and spades etc. In case of large buildings and deep excavation, mechanical earth cutting equipment can be used.
For hard soils when the depth of excavation is less than 1.5m, the sides of the trench do not need any external support. If the soil is loose or the excavation is deeper, some sort of shoring is required to support the sides from falling.
Planking and strutting can be intermittent or continuous depending on the nature of soil and the depth of excavation. In the case of intermittent or “open” planking and strutting the entire sides of trenches are not covered.
Vertical boards (known as poling boards) of size 250 x 40mm of the required length can be placed with gaps of about 50cm. These shall be kept apart by horizontal waling of strong timber f section 100 x 100mm at a minimum spacing of 1.2m and strutted by a cross piece of 100 x 100 square.
In the case of soft soils continuous or “close” planking is adopted and the vertical boards are kept touching each other without any gap as shown.