Approximately 30 days after the concrete is poured, the expansion connection between the coping and the deck is caulked or filled with elastomeric sealant. This allows the concrete to settle and form its permanent structure. The copings should be flat on their upper surface so they will not cause damage to shoes or clothing when walking on them. The thickness of the coping depends on how high you want the water to fall before it reaches the pool floor. Thicker copings mean more water falling from a higher height. This helps reduce erosion and maintain the quality of your pool's water. Thicknesses range from 3/8 inch to 1-1/4 inches thick.