With the proper maintenance, a well built inground pool can last many years. From time to time, some renovation is required, though, and one of the most common ways to revitalize a plaster finish pool is to patch and repaint. Water balancing chemicals and sunlight over a period of time can cause the paint to stain, fade and blister away, and you need to select a good quality paint to replace it.
Pool coatings, as those in the swimming pool industry call these paints, are specially formulated for use in pools. Do not use regular acrylic or oil based exterior paint, as it cannot tolerate the chemicals used in pool water. The two main kinds of pool coatings available are epoxy and rubber based paints.
Epoxy Vs. Rubber Based Paints
Epoxy pool paints provide good resistance to algae and chemicals and have a smooth glossy finish. Although they are a little tricky to use, they can be applied to pools with concrete, plaster, aluminum or steel walls as well as fiberglass pools. Epoxy paints have a service of life of from four to six years.
Rubber based paints use natural chlorinated rubber; these pool coatings have high water and chemical resistance, good adhesiveness and a hard smooth finish. If the pool’s previous coating was also rubber based, repainting with the same type of coating will allow the two coats to combine into one thicker layer, since the new coat’s solvents will penetrate into the old coat to fuse them together.
Newer rubber based paints, however, contain less organic solvent, for environmental compliance, and cannot adhere to old paint coats as well, so you may need to sandblast the old layer of paint off. Follow the manufacturers recommendations for surface preparation. The service life of chlorinated rubber pool paint is around three years.
Swimming Pool Paint Selection
When repainting a pool that has been painted before, it is essential that you use a paint which is compatible with the previous paint coating. If you know what brand and type of paint was used earlier, this makes your job easier.
Otherwise, you need to obtain a small sample chip of the old paint from the pool and test it for composition. The test is simple enough, if a paint chip softens and dissolves when dropped into a rubber based paint solvent, it is rubber based paint, if not the paint chip is likely epoxy based.
To ensure a paint’s compatibility with the old coating, apply a small test patch in the pool. Allow 24 hours for the paint to dry and then examine the area for blistering, wrinkling, peeling or cracking. Also make a scratch with a piece of metal in the test patch and see if the two layers separate easily. If you see any of these signs, that means the two paints are incompatible and you should try a different one.
Sometimes even with the same brand and color, the paint manufacturer can change the formulation slightly and it will have a bad effect. Should you fail to find paint compatible with the old paint, you will have to totally remove the old paint from the pool.
The other factor crucial to repainting your pool is properly preparing the surface before paint application. All pool surfaces to be painted must be totally cleaned of grease, body oils, and dirt.
After cleaning, the surface must be abraded or chemically etched to enable maximum adhesion. For etching, either muriatic acid, hydrochloric acid or trisodium phosphate (TSP) is used. After preparation, the surface should have the texture of fine grit sandpaper.
Surface preparation is best done by an experienced pool service pro, since you can damage the pool lining if you are not careful. Also, if more than about 20% of the old pool paint coating is cracked or peeling, you are better off removing all the old paint layer, which involves sandblasting.
Let a pro make the call on whether this needs to be done or not. Otherwise your new paint layer could end up peeling of in the water and you will have wasted a lot of time, effort and money.
See Also: Swimming Pool Filters