How to Replaster Your Pool?

Replastering your pool is a significant home improvement project that can restore its beauty and extend its lifespan. The process involves meticulous preparation, application, and curing to ensure a durable and aesthetically pleasing finish.

Understanding Pool Replastering

Pool replastering, also known as pool resurfacing, involves applying a fresh layer of plaster to the interior surface of your swimming pool. This is typically needed when the existing plaster shows signs of wear, such as etching, staining, cracking, or exposed aggregate, which can lead to leaks, rough surfaces, and an uninviting appearance.

The successful application of new pool plaster hinges on following a structured multi-step process, from initial draining to final water treatment and ongoing maintenance.

Step-by-Step Guide to Replastering Your Pool

Replastering a pool is a complex task often best handled by professionals, but understanding the steps can help you supervise the project or decide if it's a suitable DIY endeavor for experienced individuals.

1. Drain the Pool and Relieve Hydrostatic Ground Pressure

The first critical step in any pool resurfacing project is to completely drain all water from the pool. This allows access to the pool's interior surface.

• Complete Drainage: Ensure the pool is fully empty, as any residual water can hinder surface preparation.
• Relieve Hydrostatic Pressure: This is crucial to prevent the pool shell from "floating" or cracking due to external groundwater pressure. Many pools have hydrostatic relief valves at the bottom, which automatically open as the pool drains to equalize pressure. If your pool does not have these, or if ground pressure is exceptionally high, a professional might use well points or other methods to dewater the surrounding soil. Ignoring this step can lead to severe structural damage to the pool shell.

2. Prepare the Pool Surface for Plaster

Once drained, the existing pool surface needs thorough preparation to ensure proper adhesion of the new plaster. This step is vital for the longevity of the new finish.

• Remove Loose Material: Chip away any loose, delaminated, or hollow-sounding plaster. Use tools like chisels or jackhammers carefully to avoid damaging the underlying concrete shell.
• Clean Debris: Power wash the entire surface to remove dirt, algae, oils, and any other contaminants. A clean surface is essential for proper bonding.
• Repair Cracks: Address any structural cracks in the pool shell. These may need to be V-cut and filled with hydraulic cement or specialized crack repair materials before plastering.

3. Acid Wash Surface

An acid wash is performed to etch the existing plaster surface, creating a rough profile that enhances the bond between the old and new materials.

• Chemical Application: A diluted acid solution (typically muriatic acid) is applied to the pool surface.
• Etching: The acid etches the surface, removing thin layers of plaster, exposing a fresh, porous layer, and ensuring the new plaster adheres effectively.
• Safety Precautions: Always use proper safety gear, including gloves, eye protection, and respirators, and ensure adequate ventilation when working with acids. Neutralize and rinse thoroughly after the acid wash.

4. Apply a Bond Coat

Applying a bond coat is a critical step that ensures maximum adhesion of the new plaster to the prepared surface.

• Purpose: The bond coat acts as a primer, creating a strong, adhesive layer between the old, prepared surface and the new plaster. It helps prevent delamination and ensures a uniform cure.
• Application: Bond coats are typically a polymer-modified cementitious material applied thinly and evenly to the entire surface. They are usually sprayed or brushed on.
• Timing: The bond coat must be applied according to the manufacturer's instructions, often allowing for a specific drying time before plaster application.

5. Fill and Treat the Pool

Once the new plaster has been applied and allowed to set (typically 24-48 hours, depending on the plaster type and weather conditions), the pool is ready to be filled. This is a crucial step for the proper curing of the plaster.

• Controlled Filling: Fill the pool slowly and continuously to avoid streaking or plaster damage. Use a hose that is free of mineral deposits, often placed on a bucket or piece of wood to prevent it from marring the fresh plaster.
• Initial Water Treatment: Immediately after filling, begin the "plaster start-up" chemical treatment process. This involves carefully balancing the water chemistry, especially calcium hardness, alkalinity, and pH, to prevent plaster dusting, scaling, or etching.
• Brushing: For the first few days to weeks, the new plaster requires regular brushing (2-3 times daily) with a soft pool brush to remove plaster dust and aid in the curing process. Do not vacuum the pool for at least 7-10 days, and only use a brush vacuum head.

6. Perform Maintenance Tasks

Ongoing maintenance is essential to preserve the beauty and integrity of your newly replastered pool.

• Consistent Water Chemistry: Maintain proper water balance (pH, alkalinity, calcium hardness, cyanuric acid) at all times. Imbalanced water can quickly damage new plaster.
• Regular Brushing: Continue to brush the pool walls and floor regularly, especially during the first month, to remove any residual plaster dust and prevent calcium deposits.
• Monitoring: Keep an eye out for any unusual spots, streaks, or changes in the plaster surface, addressing them promptly.
• Avoiding Aggressive Cleaning: Refrain from using harsh chemicals or abrasive cleaning tools on the new plaster for several months.

By meticulously following these steps, you can achieve a beautifully replastered pool that provides years of enjoyment.