Depending on the type of paint, pools needs to be repainted every 3 to 5 years. It is okay to paint over 1 or 2 coats, but more than that may cause a problem with the new paint adhering properly. For this article, we will assume that all paint is being removed by sandblasting, and that chlorinated rubber paint will be applied.
Sandblasting will remove built up paint, dirt, and most stains. It leaves behind a smooth, clean surface. The drawback to sandblasting is that the drain must be covered before you begin, and the sand must be removed from the pool and discarded afterward. On the other hand, sandblasting will eliminate most foreign particles and provide you with a completely renewed work surface.
Make Necessary Repairs
Any repairs or caulking that needs to be done should be completed after the sandblasting cleanup is complete. This is also the point at which trim and decorative parts should be removed and put in a safe place.
Etching the Surface
Using a concrete cleaner such as muriatic acid, etch the pool surface. Etching means that the acid will literally create tiny holes in the concrete. When the paint is applied, it will soak into these small holes and fill the with paint, achieving a better, longer lasting bond between the paint and concrete. The solution should stand for at least 10 minutes before being rinsed off. Wear full safety gear when working with muriatic acid.
Clean the Surface
Rinse the pool thoroughly after using muriatic acid. Using trisodium phosphate, clean the surface of the pool. TSP will remove dirt, grime and grease, and help to further prime the surface for painting. Rinse well again to remove the TSP solution. Allow the pool to dry completely before applying the primer coat of paint.
Apply the Paint
Using a paint roller, apply the paint with long, slow strokes. A thick coat of paint needs to be applied, and great care should be taken to coat even the most difficult places to reach. It is okay if you are not able to reach all areas with the roller, as the remaining spots can be hand-brushed.
Hand Brush as Needed
Use a well-made paint brush for the places that can not be reached with a roller. Follow the same two-coat procedure, allowing the first coat to dry completely before applying the second coat. For best results, apply the primer coat and then apply the first trim coat, then repeat the process.
Replace Trim and Hardware
When the paint has dried, replace the trim and hardware that was removed when you began. Inspect the finished job with a critical eye, and make any necessary touch-ups. Remember, painting the pool doesn't have to be done very often, so make it the best job possible with an eye towards the finer details.