How to Re-Plaster a Swimming Pool
Most modern swimming pools are gunited or spray plastered with a specialized mortar. In time, the plaster inside pools begins to flake and chip and the problem has to be addressed. Most of the damage is caused not by the pool chemicals, as you may imagine, but by groundwater attacking the surface from behind. Naturally occurring minerals combine with the groundwater and seep into the concrete, eventually reaching the pool's interior. Replastering is the best option because it will effectively increase the thickness and strengthen your pool's walls. Does this Spark an idea?
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Things You'll Need
- Hose
- Detergent
- Scrubbing brush
- Wire brush
- Putty knife or cold chisel
- Hammer
- Concrete sandpaper
- Muriatic acid
- Bonding agent
- Roller of paint brushes
- Pool plaster
- Concrete mixer
- Trowels
- Pool finishing plaster
- Pool coating or paint
Instructions
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1
Turn off the pump and empty the pool. Scrub the entire surface with detergent. Many ecologically friendly detergents are available and will not give off harmful fumes. Allow the walls to dry.
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2
Scrub with a wire brush to loosen flaky areas. Pry particularly bad areas off with a hammer and putty knife or chisel. Sand all rough areas with coarse grit sandpaper until the entire surface is smooth.
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3
Acid wash the pool. Wear protective goggles, face mask and clothing for this step. Mix the acid with water according to the manufacturer's directions and brush muriatic acid over the entire surface of the pool, one section at a time. It will bubble for a while. Once it has stopped reacting with the existing concrete, hose it off immediately to prevent it from weakening the concrete. Hose down the pool walls thoroughly with water. Allow the surfaces to dry.
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Apply a bonding coat with a brush or roller. This is essential to facilitate a strong bond between the new and old plaster. Allow it to dry overnight.
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Mix the pool plaster according to the manufacturer's directions. Pool plaster dries rapidly and has to be mixed in batches, ideally with a mechanized concrete mixer. Dip a trowel into the concrete mixer and splat it onto a section of pool wall. Spread and level it with a swimming pool trowel to an even thickness of 3/8 inch, making it as smooth as possible. Start at one end of the pool and work your way to the other until the entire interior is covered with a coating of plaster.
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Allow the plaster to dry. Repeat the plastering process with a 1/2-inch thick coating of finishing plaster. When it is completely dry, apply a pool paint or resin coating with a roller. Fill the pool again and start the pump only once this the coating is completely dry.
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Tips & Warnings
When mixing swimming pool plaster, add the plaster to the water --- not the other way around --- to avoid lumps.
References
- Photo Credit Brand X Pictures/Brand X Pictures/Getty Images
