The surface of any patio or path should have a built in slope to ensure that rainwater drains efficiently away. This gradient should be approximately 1 in 70 to 80 (2.5 cm per 2 m or 1 in per 6 ft). This will create a slope that is steep enough to make sure that water does not pool on the surface, yet is imperceptible to the eye.

Work out the combined depth of your sub-base and surface material and mark this as a line at the same distance from the top of each of a number of levelling pegs. You will need enough pegs to form a 2x2 m (or 6x6 ft) grid across your patio or path site. You may also find it useful to also mark on the depths of each layer, perhaps in different colours to avoid confusion.

When you have excavated the area and tamped the base firmly down, insert a row of these pegs into the base where the top of the slope will be, so that the combined depth mark is at soil level. These pegs should be placed 2 m (or 6 ft) apart. The top of the peg should indicate where the top of the finished surface will be.

Insert a second row of pegs 2 m (or 6 ft) down the slope, again to the marked level. Place a 'shim' (an offcut piece of wood 2.5 cm or 1 in thick) on top of each peg in the second row in turn. Place a plank on top of the first peg and the peg with the shim. Lay a spirit level on top of the plank, and then push the second peg deeper into the soil until the top of the shim and the upper peg are level.

Remove the shim and repeat for all the pegs in the second row, and then continue adding rows down the slope in this manner until you have covered the area.

When you have finished positioning all the pegs, rake and remove the soil so that it is level with the mark on each peg. Add the subsequent layers (hardcore, sand and so on) to the other levels marked on your pegs.