In this method, vertical timber sheeting consisting of the planks about 8 to 10 cm. thick are driven around the boundary of the proposed excavation to a depth below the base of the excavation. The soil between the sheeting is excavated. The sheeting is held in place by a system of Wales and struts. The Wales are the horizontal beams running parallel to the excavation wall. The Wales are supported by the horizontal struts which extend from the side of the excavations.

However, if the excavations are relatively wide, it becomes economical to support the Wales by inclined struts, known as rakers (fig-6.6.2b). For inclined struts to be successful, it is essential that the soil in the base of the excavation is strong enough to provide adequate reaction.

If the soil can temporarily support itself an excavation of limited depth without an external support, the timber sheeting can be installed in the open or in a partially completed excavation. Vertical timber sheetings are economical up to a depth of 4 to 6 meter.