Typical external rendering is Pebble dashing, Tyrolean and plainface finish. Plainface finish is the most common. It should be applied to a well-keyed backing coat called a scratch coat.
The scratch coat should be about 10mm thick and ruled to a true surface and keyed with a comb scratcher. This is now ready to receive the Floating coat. The scratch coat should be left at least 24 hours before the floating coat is applied.