Transform Your Gunite Pool: Empty, Prep, And Paint

Gunite pools are durable and long-lasting, but they may require refinishing to repair wear and tear or to update their appearance. Before painting your inground gunite pool, it is important to empty and prep the pool. This includes draining the pool, opening the hydrostats, and ensuring that the pool is completely dry. The weather and temperature play a crucial role in the painting process, so it is best to avoid painting if the temperature is below 40°F, above 90°F, or if it is extremely humid. Once the pool is empty and dry, you can start the painting process, which involves using a primer and paint suitable for gunite pools, such as epoxy paint. However, it is important to note that painting a gunite pool may not be the best long-term solution due to the short lifespan of pool paints and the potential for peeling and maintenance issues.

Prep the pool: fix cracks and hollow spots, and scrape away loose paint

Prep the pool

Before painting your inground gunite pool, it's important to fix any cracks and hollow spots and scrape away loose paint and plaster.

Fixing cracks

Firstly, identify any cracks in the pool surface. Most concrete pools will crack at some point, especially older pools. Surface cracks are those that only go through the paint or pool finish, whereas deeper cracks go through the layer of concrete beneath the pool finish and can cause substantial leaks.

To fix surface cracks, first widen them using a grinder or drill. Then, fill the crack with a special epoxy sealant. The advantage of this method is that the filler is ejected at high pressure, filling the crack all the way through. Alternatively, you can fill the crack with a pool patching mixture. Lightly moisten the concrete edges of the crack, then use a flat trowel or putty knife to apply the mixture. Gently push the mix into the crack to remove all air, then scrape off any excess material.

Fixing hollow spots

To identify hollow spots, drag the floor of the pool with a heavy chain and listen for a hollow sound, or tap the pool floor with a wooden pole. Chip up any delaminated areas, wearing gloves and eye protection.

Scrape away loose paint and plaster

Use a hammer and chisel to remove any loose plaster that is not bonded to the pool surface. Then, chisel some divots and pock marks into the surface that will be patched to help your new plaster patch bond to the existing surface. Acid wash the surface to be repaired, then mix your pool patch to a peanut butter consistency. If the plaster is a custom colour, you can add cement dyes or pigments.

Drain the pool and open hydrostats

Before you begin painting your inground gunite pool, you must first drain the pool and open the hydrostats. This is a crucial step to prevent damage to your pool from hydrostatic pressure.

Understanding Hydrostatic Pressure

Hydrostatic pressure refers to the pressure exerted by groundwater surrounding and underlying your pool. This pressure can cause significant damage if not properly managed. The weight of the water around your pool can put immense pressure on its walls and floor, potentially leading to cracking or even the pool "floating" out of the ground.

Locating and Opening Hydrostats

Hydrostats, or hydrostatic pressure valves, are typically located in the deep end of your pool. They may be covered with plaster, so look for small white plastic circles in the floor. To open them, chip away the plaster using a chisel or similar tool, then use large straight pliers to twist and remove the cap. This will allow water to escape from under the pool, relieving the pressure.

Draining the Pool

Draining an inground gunite pool can be tricky, and improper drainage can lead to issues like the "inground pool pop-up," where the ground rises and causes the pool to crack. It is recommended to seek professional help if you are unsure about the process. If you decide to drain the pool yourself, follow these general steps:

• Rent a sump pump from a hardware store.
• Attach a hose to the pump and lower it into the deepest section of the pool.
• Ensure the other end of the hose is draining into a sewer drain pipe.
• Turn on the pump and periodically check that it is draining properly.

Precautions

• Avoid draining your pool after heavy rainfall or if it is located in a wet area. Excessive groundwater can increase the risk of hydrostatic pressure issues.
• Do not leave the pool empty for an extended period, as this can also impact the hydrostatic pressure.
• Be cautious of hydrostatic valve failure, as mentioned by some pool owners.
• Keep in mind that draining a pool should be a last resort for cleaning or repairs. Most pools should only be drained and refilled every 5-7 years or when necessary for maintenance.

Acid wash the pool surfaces to roughen them

Acid washing your pool is a vital step in preparing the surface for painting. It opens up the pores of the surface, allowing the paint to adhere better and create a strong bond. Here's a step-by-step guide on how to acid wash your inground gunite pool:

Step 1: Prepare the Acid Solution

Mix a 10% solution of muriatic acid with water. Muriatic acid is typically available at pool supply or home improvement stores. Remember to always pour the acid into the water, never the other way around. The amount of acid and water needed will depend on the strength of the acid. For example, one gallon of 30% muriatic acid mixed with two gallons of water will give you a 10% solution.

Step 2: Apply the Acid Solution

Using a long-handled brush or a garden hose, apply the acid solution liberally to the pool surfaces. Make sure to wear protective eyewear and gloves during this step, as acid etching can be hazardous. Start with the walls and then move on to the floor. The acid will start to bubble when applied.

Step 3: Rinse the Surface

Once the bubbling stops, rinse the acid solution off with clear water. Splash a small amount of water on the surface to test if it is properly etched. If the water soaks in quickly, the surface is ready. If not, you may need to repeat the etching process or use a stronger acid solution.

Step 4: Neutralize and Rinse

After etching, it is important to neutralize any remaining acid. Use a pool washing solution containing tri-sodium phosphate (TSP) and follow the manufacturer's instructions. Rinse the pool thoroughly to remove any acid or TSP residue.

Step 5: Dry the Pool

Pump out any remaining water from the pool and let it dry completely. This step is crucial, as you want to ensure the pool surface is dry before applying any paint or primer. Depending on the environment, this process can take around 3 to 5 days.

Acid washing is an effective way to roughen the surfaces of your inground gunite pool, providing a better base for the paint to adhere to. Always exercise caution when working with acid and follow the manufacturer's instructions for your safety.

Choose the right paint: epoxy or acrylic

When it comes to choosing the right paint for your inground gunite pool, you'll generally be deciding between epoxy and acrylic. Both options have their advantages and drawbacks, and the right choice for your pool will depend on various factors, including your budget, the condition of your pool, and the amount of time you're willing to spend on the project.

Epoxy paint is generally considered the highest-quality type of pool paint. It provides a smooth, flawless finish and is highly durable. If you're painting a gunite pool, you'll need to use an epoxy primer, and for especially rough surfaces like bare concrete or gunite, you can get a primer specifically designed for these surfaces. Epoxy paint has an additive that starts a reaction when mixed into the paint, and each batch should be used within a few hours. Keep in mind that epoxy paint can be more expensive than other options, and it may not be suitable for pools that have been painted before, as it may not adhere well and can lead to uneven thickness and coverage.

Acrylic paint, on the other hand, is a more affordable option and is often chosen for its ease of use. Acrylic paint is also more flexible than epoxy, making it a good choice for older pools that may have some movement or shifting. Additionally, acrylic paint can be applied in cooler temperatures, making it a good choice for painting pools during the off-season or in colder climates. However, it's important to note that acrylic paints have shorter lifespans than epoxy paints.

Another factor to consider is the environmental conditions during the painting process. Epoxy paint is typically applied in warmer temperatures, above 50°F (10°C). Acrylic paint, on the other hand, can be applied in temperatures as low as 40°F (4°C). Both types of paint should be applied in dry conditions, as rain or high humidity can affect the curing process and the final finish.

Finally, it's important to consider the long-term maintenance and upkeep of your pool. While epoxy paint may last longer initially, proper maintenance, such as regular cleaning and chemical balancing, can extend the lifespan of any paint job. Additionally, the use of pool covers and regular resurfacing can also help protect your paint and keep your pool in good condition.

In summary, both epoxy and acrylic paints have their advantages and considerations. Epoxy paint offers a more durable and long-lasting finish but may be more expensive and require specific conditions for application. Acrylic paint is more affordable and flexible but may not last as long. Ultimately, the right choice depends on your specific needs, budget, and the condition of your pool.

Apply the paint, starting at the deep end

Now that your inground gunite pool is completely dry, it's time to start painting, starting from the deep end. Use a telescoping pole to reach all the way up the walls. Use a low-nap roller, 3/8-inch nap or less, for smooth surfaces. A 5-gallon bucket with a grid works better than a low, flat paint pan. Make sure to mix your paint thoroughly. Use a power drill with a mixing paddle to ensure that your pool paint is mixed properly. Epoxy paints have a limited pot life, so be sure to use each batch within a few hours.

If your pool has never been painted before, or if the surface is very rough, consider adding a primer to improve the bond and extend the life of your paint. Depending on your pool surface type, there are many primers available, including epoxy and gunite. If you're using epoxy paint, be sure to use an epoxy primer, especially if you have a rough surface like bare concrete or gunite.

Keep in mind that painting a pool is a tedious job, but it will be worth it in the end. Take your time and follow the necessary precautions to ensure a successful paint job. Remember to avoid painting if the temperature is below 40°F, above 90°F, or if it is extremely humid. It is also important to minimize debris from landing in your freshly painted pool.

Frequently asked questions