Question: how to pebble dash a wall?
Answer: Trowel on the mixture onto the wall to be pebble dashed. Keep the trowel level and use its edge to create a smooth, flat layer of the base on the wall. Let the base dry for about an hour, then rake the surface with a notched trowel to create a grooved surface to help the second coat adhere. Let it dry for 24 hours.