- 1). Drain the pool past the location of the crack and allow the area to dry. Using a grinder or diamond blade saw, cut around the crack until it's a half-inch deep and one inch longer on each end. Clean the crack, brushing away all debris, and allow it to dry completely.
- 2). Caulk the crack, still leaving it a fourth of an inch deep for a plaster covering. While you're waiting for the caulk to dry, mix up your pool patch materials until the mixture resembles loose peanut butter.
- 3). Dampen the surface and add pool patch mixture to the crack with a trowel or putty knife. Push it into the crevice, leaving no room for air bubbles. Smooth the area and use a sponge to make it resemble the plaster around it.
- 4). If it will take some time for the water level to reach the patch again, cover the area with a wet towel to keep it damp. Keeping the area wet will prevent the plaster from cracking again. Fill the pool as soon as you can.
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