How to Repair Plaster in a Pool Whether It’s Empty or Full

Pool plaster repairs are an essential part of maintaining a well-functioning pool, ensuring the surface remains smooth and free from leaks. Over time, cracks, gouges, or loose patches can develop in the plaster, often due to wear and tear or accidents in the pool. These issues need to be addressed promptly to avoid worsening damage or potential water leakage. Whether your pool is empty or full, repairing the plaster is a manageable task if done correctly. In this guide, we'll walk you through the steps of repairing pool plaster, ensuring a smooth, durable finish.

What You’ll Need for Pool Plaster Repair

Before starting the repair process, gather all necessary tools and materials. This will ensure you can complete the job without having to stop midway.

• Submersible pump
• Drainage hose
• Hammer
• Masonry chisel
• Paint scraper
• Large pliers
• Angle grinder or masonry saw with a diamond blade
• Pool trowel or putty knife
• Grouting sponges
• Wire brush
• Small soft-tipped brush (like a paintbrush)
• Wooden pole
• Spray bottle filled with water
• Garden hose and spray nozzle
• Pool plaster
• Epoxy putty (for underwater repairs)
• Underwater sealer
• Regular muriatic acid
• Soda ash
• Acid-resistant gloves, goggles, ear protection, and long-sleeved clothing for safety

Important: Pool plaster repair involves working with potentially hazardous materials and tools such as grinders, concrete saws, and acid. If you feel uncomfortable with these tasks, it’s best to consult a professional.

Pool Plaster Repair: Empty Pool

When your pool is empty, the repair process can be more straightforward, especially for cracks or gouges that go deep into the surface. Here’s how you can repair pool plaster in an empty pool:

1. Prepare the Pool
   Ensure the pool is drained and dry. Follow safe guidelines for draining your pool to avoid any structural damage.

2. Cut Out the Damaged Area
   Use the angle grinder or masonry saw to cut around the crack or damaged area. Make cuts that are about ½ inch deep, creating a dovetail shape. Extend the crack by about one inch on both ends and remove the damaged plaster.

3. Clean and Prepare the Surface
   Rinse the area thoroughly to remove dust and debris. Allow it to dry completely, then use a soft brush to clean any remaining dirt.

4. Apply Underwater Sealer
   Once the area is dry, apply a bead of underwater sealer along the edges of the crack, leaving about ⅜ of an inch of space for the new plaster.

5. Mix and Apply Pool Plaster
   Mix the pool plaster with a bonding agent until it reaches the consistency of peanut butter—thick enough to stay in place but easy to spread. Use a damp grouting sponge to moisten the crack perimeter, then apply the plaster using a trowel or putty knife. Press it into the crack to remove air bubbles.

6. Finish the Patch
   Smooth the surface with the edge of the trowel or putty knife, then dab with a damp sponge to mimic the surrounding surface texture.

7. Cover the Patch
   If you won’t be refilling the pool right away, cover the patched area with a damp towel or old bed sheets to prevent the plaster from drying out too quickly. This helps avoid shrinkage and cracking.

8. Refill the Pool
   Once the plaster is fully set and cured, refill the pool with water. The plaster will continue to cure better underwater, ensuring long-lasting repairs.

Pool Plaster Repair: Patching Loose or Bubbling Plaster

If your pool has loose or bubbling plaster rather than cracks, you’ll need to address these areas by removing the damaged plaster and applying a new coat. This method is also done when the pool is empty.

1. Identify Loose Areas
   Use a hammer and masonry chisel to knock off any loose plaster. Tap around the pool floor with a wooden pole, listening for hollow sounds indicating more loose plaster. Remove all damaged areas.

2. Create a Rough Surface
   Use the chisel to create small divots in the surface of the area being patched. This rough texture helps the new plaster adhere better.

3. Acid Wash (Optional)
   Apply an acid wash to clean the surface, removing stains and debris. If your pool needs a complete acid wash, this is an ideal time to do it.

4. Mix New Plaster
   Mix the plaster with a bonding agent until it reaches a thick but spreadable consistency. Add cement pigment if needed to match the pool's existing color.

5. Apply the New Plaster
   Using a wet grouting sponge, moisten the area before applying the plaster. Then use a trowel to fill in the divots, smoothing it over the surface to ensure it blends seamlessly with the surrounding area.

6. Refill the Pool
   Cover the patch with wet towels or sheets to prevent it from drying out too quickly. Once the plaster has set, refill the pool with water.

Pool Plaster Repair: Full Pool (Underwater Repair)

If you need to repair plaster while the pool is still full, you can use underwater epoxy putty or pool plaster for small cracks and gouges. Here’s how to do it:

1. Prepare the Area
   Rake the crack open with a paint scraper to ensure the surface is clean and ready for repair. Use a wire brush to remove algae and any remaining debris from the area.

2. Choose Your Repair Material
   For small cracks, use underwater epoxy putty. Mix equal parts of the putty and shape it into a ball or rope to fit the crack. For larger areas, mix pool plaster according to the manufacturer’s instructions.

3. Apply the Repair Material
   For epoxy putty, push the putty into the crack and smooth the edges flat against the pool surface. For pool plaster, roll it into a ball and take it into the water. Press it into the crack with a trowel or putty knife. Smooth the edges for a seamless finish.

4. Allow the Repair to Set
   Once the repair is complete, allow the material to set and cure before using the pool again.

When to Hire a Professional

In some cases, the damage may be extensive enough that it's more cost-effective and safer to hire a professional to replace or repair your pool plaster. If you’re unsure about your ability to complete the repairs, it’s worth consulting an expert who specializes in pool resurfacing. Hiring a professional ensures the work is done right, and it can save you money in the long run by avoiding potential mistakes.

Conclusion

Pool plaster repairs don’t have to be complicated or expensive. Whether you're fixing cracks in an empty pool or repairing a surface while the pool is still full, following the correct steps will ensure the plaster is applied correctly, providing a smooth, long-lasting finish. By addressing any issues quickly, you can keep your pool in great shape for years to come.