Like a picture frame, the rim around the pool controls the way in which the surface of the water is perceived. Edges – whether angled, curved or straight – offer the opportunity to break down or build up barriers between land and water in creative ways. Crossing the threshold to the water may be as gradual as wading into the ocean or as abrupt as diving into a deep lake.

The ledge of the pool is formed from a concrete bond beam capped by an element called the coping. As the finished edge to the pool, the coping directs water to the drains or channels and prevents it from seeping behind the pool shell and damaging the structure. While typically 8 to 12 inches (20-30 cm) wide, the coping can be virtually any size to form a surface on which to walk around the pool, as well as an area from which to dive or jump into the water.

The coping’s effect on the design of the pool, however, extends far beyond its functional role. As a transitional element between water and land, it defines the shape of the basin and helps to establish the relationship between the pool and its surroundings.