If you have a fiberglass swimming pool, the painting process is going to be completely different than it would be if you have a concrete swimming pool. We will briefly outline what is involved for each. Fiberglass swimming pools require a gel coat to be removed and then reapplied. Concrete swimming pools have many different products that can be used in the painting process. The processes are unique for each type of pool, so do not ever use products meant for fiberglass on concrete or vice versa.
Of course, since inground pools typically use chlorinated water, special paint is needed to protect the pool surface material and withstand moisture, chemicals and alkali (from the cement in concrete pools). Other considerations are the prolonged exposure to the sun, ease of cleaning, susceptibility to chipping and cracking, and ease of application, as well as a pleasing appearance. Paints with bases of Chlorinated rubber, Epoxy, and Water are all used, depending on the type of material used for constructing the pool. Of these, epoxy base paints are the longest lasting, with a typical life of 7-10 years. Chlorinated rubber paint will last about 3-5 years, and acrylic water based pool paint will last around 2-3 years.
When to Paint
You want to paint when the weather is warm, but not in too much direct sunlight. Harsh sunlight can cause the paints to dry to fast and not cure properly. Check the label of the paint you intend to use for ideal conditions. A nice summer, spring or fall day is all you need. It is normally best to paint in the late afternoon when the direct sun is not very intense. That will allow it to dry out of direct sunlight in the later evening.
Fiberglass pool restorations should not be done during rainy seasons because water is harmful to the process. Remember to take curing time into consideration when looking at the weather forecast- consult your paint manufacturers instructions for required time.
Painting a Concrete Swimming Pool
Before painting a concrete pool, you need to determine what type of paint was used last and how many times it has been painted over in the past or how many layers of paint are on it now. If you are having trouble determining the type of paint, use a knife blade to remove a chip of paint and have your paint dealer analyze it for you. You can also determine the number of layers of paint by chipping the surface and counting the number of layers.
If there are more than three layers of paint on your pool already, you should strongly consider removing all previous layers. The pool may require sandblasting to remove the old layers of paint. Again, there are two main types of paint used on concrete swimming pools. They are epoxy paint and chlorinated rubber paint. Epoxy paint generally lasts about 5 to 7 years, while chlorinated rubber paint only lasts 2 or 3 years.
Steps for Painting Concrete Pools
1. Prepare the surface. Preparation is often the majority of the work when it comes to painting a concrete pool, and how good a job of surface prep you do will determine how successful your painting project is. If there are more than three layers of old paint, then you may wish to sandblast the layers completely off before painting, especially for old epoxy paint.
2. Thoroughly clean the area to be painted. Begin with a very strong detergent such as Tri Sodium Phosphate. Repeat this step if you see any stubborn stains left behind. Make sure to rinse very thoroughly. You do not want any detergent left behind as it will cause the paint to not stick properly.
3. Etch the surface. This can be done with a variety of etching cleaners available or with plain Muratic acid. Apply the Muratic acid or etching cleaner according to the directions and allow it soak in. Brush it hard and fast for 10 to 20 minutes and then rinse it off well. If any stains or dirt remains after this step, repeat steps 2 and 3 until perfectly clean. Preparation is everything. Beware of the toxic fumes when using Muratic acid. Note that it is important to remove all muriatic acid from the pool surface before painting, or the paint will have poor adherancy.
4. Thoroughly dry all surfaces to be painted prior to doing any repairs or applying any paint. The moisture content needs to be below 19% to paint. If you do not have access to a moisture meter, just make certain everything is very dry. One way to test for moisture is to place a rubber floor mat from your car in the center of the pool and let it sit there for a few hours. Next, lift the mat up and if there is any discoloration or moisture on the mat then it is not dry enough yet.
5. Repair any cracks or holes before painting. Now is the time to make any repairs that are needed. Use a patching material that is recommended for cement pools and allow the repairs to dry thoroughly before continuing on to the next step.
6. Prime as needed, Read the instructions for the type of paint you choose carefully, for instance, epoxy paints probably require a primer to be used. See if you need to prime first and do so if needed. Most chlorinated rubber paints can be applied without using primer.
7. Apply Paint. Be sure to follow any manufacturer’s directions when using the paint you selected because some have different procedures. We recommend putting on two coats of paint. Allow the recommended number hours or days to dry in between coats of paint. Most paints and coatings that you would use on a pool can be sprayed on, however we recommend using a roller. Use a brush on the edges and roll out everything in between. Using a roller allows for a better film build.
8. Allow the paint to cure fully before putting the pool back into service. Read the label for the specific curing time of the paint you are using. Most paints used will take 7 to 10 days to fully cure. Curing is not the same as drying. The paint will feel and look dry 12 to 24 hours after painting, but the paint still needs to cure before it reaches it’s full durability and potential.
That is all there is to painting a concrete pool’s surface. Now let’s look at what is involved in painting a fiberglass pool.
Painting a Fiberglass Swimming Pool
Painting a fiberglass pool is very different than painting a concrete pool. Fiberglass pools have a gel coat that should only need restored about every 20 years or so. There are a few basic steps involved in restoring the surface of a fiberglass pool and we will list them here:
Steps to Restore
1. Remove the old gel coat. Sandblasting is the best way to do this. A rented sandblaster is not heavy duty enough to do large pools, but may work for hot tubs or very small pools. You will need to have a contractor come in to sandblast the pool in most cases. Hand sanding with an orbital random sander can be done, but is a lot of work! Remove all gel coating, but be careful not to damage the fiberglass resin underneath.
2. Clean thoroughly. Use a detergent to clean any stains and all dirt from the pool and use a pool solvent right before painting and allow it to dry completely.
3. Apply the first gel coat with a roller. Cover the entire pool. Each gallon should cover about 60 to 80 square feet. Most pools require between 2 and 5 pails of gel coating.
4. Depending on the temperature, it can take several hours for the first coat to dry. When the bottom of the pool appears completely dry, roll on a second gel coat. Try to do both coats in the same day if possible. Waiting til the next day is not recommended. Be sure to read the paint’s instructions and look out for any differences in application directions as different brands may vary.
5. Allow to dry and cure. Gel coats typically only take a couple hours to dry. The pool however, needs to remain empty until it is fully cured. They take between 3 and 5 days to cure depending on conditions. Refer to the manufacturer’s recommendations for the gel coat you choose for specific curing times.