Painting a Fiberglass Pool

Painting a Fiberglass Pool

Has your fiberglass pool lost its original luster? Is it stained and dirty? Or does it have spider cracks in the gel coat? Painting a fiberglass pool can be a great DIY pool restoration project. Epoxy paint bonds well to fiberglass and wears well, becoming thin over time. It will need to be redone again in 5-7 years, but is a cost effective alternative to applying a new gel coat to a fiberglass pool.

1. Order Pool Paint and Painting Supplies

fiberglass pool paint and painting supplies

Epoxy pool paint is the only suitable material to paint a fiberglass pool. Buy enough to paint two coats for a long lasting finish. Measure your pool carefully to add up all the surface area of the floor, walls and steps, then buy more than enough Epoxy pool paint to cover the surface twice.

Additional pool painting supplies include:

  • Paint rollers (3/8in low nap), roller frames, extension poles
  • Paint brushes for cutting in corners
  • Masking tape
  • 5 gal bucket with paint screen
  • Scrub brushes on poles
  • Sanding brushes on poles
  • 2 gallon flower watering can
  • Dishwasher detergent
  • TSP Cleanser (Tri Sodium Phosphate)

2. Drain the Pool

use a submersible pump to drain the pool before painting the pool

Some pool pumps will drain the pool completely through the main drain, but it’s more common that they will lose prime before pumping the last few hundred gallons out of the pool. If you have a small submersible pump of some size, it should be able to pump out the remaining water, running the hose up and out the shallow end of the pool. For very deep pools, you may need to rent or buy a small (1/3hp) submersible pump (sump pump) to remove the rest of the water, or to dewater the pool quickly in the event of a heavy rainstorm after draining.

Speaking of weather, a pool painting project needs to be completed quickly, within a week if possible. Oily, dusty pollutants deposit on the surface, affecting the bond before painting – and rain after painting can affect the cure time. Be sure to have all supplies ready to go before beginning, with a dry and calm weather forecast in the week ahead.

Draining a fiberglass pool can be of particular concern during rainy periods when the water table is high, and fiberglass pools that are not solidly supported can be at risk for shifting when the water is drained from the pool. It’s never happened to me or anyone I know, but just to let you know, it is a possibility.

Once all of the water is drained from the pool, use a large sponge and buckets (or a small pump) to remove any standing water in the drain, skimmer, behind lights, steps, etc.

3. Clean the Pool

TSP surface cleaner

It is imperative to remove scale, dirt and oils from the pool surface. Paint will not adhere to dirty, scaly or oily surfaces, and will peel off, chip off or pop off in a very short time. Start with 1/4 cup of a low suds dishwasher detergent, dissolved into the flower watering can with 2 gallons of warm water. Pour the soapy solution along the walls, while a helper uses the scrub brush on a pole (or by hand), to scrub every inch of the walls, from top to bottom. Stop scrubbing every 10 feet or so, and rinse down the scrubbed sections. After the walls and steps are scrubbed vigorously and rinsed, move to the floor. Rinse the floor and pump out the pool.

Next, repeat the process with TSP, a powerful degreaser available at any home store. Mix again with warm water and scrub the walls, steps and floor thoroughly, rinsing quickly to keep it from drying on the surface. Rinse the entire pool again, and pump out all waste water in the deep end.

4. Sand the Fiberglass Surfaces

Sanding the pool is an important step to roughen up the surface and improve paint adhesion. With plaster pools, an acid wash is done to accomplish the same thing, but on fiberglass pools, buy 2 sanding pads mounted on wooden poles, with #80 grit sandpaper. You don’t need to rub the gel coat right off the pool, just one or two passes with light pressure is sufficient. Sand in the same direction all the time, parallel sanding grooves hold paint better than cross-hatch or sanding in all directions. Certain areas with transition curves, around steps or lights for example, should be sanded by hand (without the pole) for more control. When the sanding is completed, hose the pool down once more and pump out the water again, getting every last drop.

5. Let the Pool Dry

Some plaster pools can take up to a week to dry, but in dry, low humidity weather, a fiberglass pool can be dry and ready to paint in just 2 days, in most cases. To be sure it’s dry before painting, use masking tape to secure several large pieces of clear plastic to the pool walls and floor. After a few hours in the sun, inspect the squares to see if any moisture is on the inside of the plastic. Pay close attention to any areas of fiberglass where the gelcoat is worn thin or has spider web cracks, or very small surface crazing. If there has been any rain or heavy morning dew during the drying period, pump it out or mop it up asap. When you are certain that the pool is dry, check the weather again to have at least 4 days of dry weather ahead.

6. Paint the Pool

Just before painting the pool, do a dry wipe of the pool walls, steps and floor, with clean towels duct taped to your sanding poles. This step is recommended to sop up any saps, oils, dust and pollutants that have blown into the pool during drying. Mix up a few gallons of the epoxy paint (each gallon comes in 2 cans) completely, while your helper tapes off the pool coping, or any non-removable features that will remain unpainted. Pour the mixed paint into your 5 gallon painting bucket with paint screen (much better than flat paint trays). After the sun burns off any morning dew, start in the deep end with two painters, both covering one half of the pool.

Use long overlapping strokes of even pressure to obtain complete coverage. Two people can paint an average pool in 1-2 hours. Let the first coat fully dry (4-8 hours), and then add another coat quickly, best if you can do it on the same day. Follow label instructions for drying time recommendations between coats, and before filling the pool. Note that on the second coat, you may use about 20% less paint than on the first coat.

7. Fill the Pool

Follow instructions on your paint container for recommended drying times for painted fiberglass pools. Depending on the weather (temperature, humidity, rain, fog), more or less drying time will be needed, generally 4-7 days before you can fill the pool. When you do fill the pool, place the hose in the deep end, not in the shallow end, so that water won’t run in a small river down the pool floor. Balance the water immediately after starting the filter, with additional care that alkalinity is above 100 ppm and pH remains above 7.4 at all times, to protect your new paint job.

32 thoughts on “Painting a Fiberglass Pool

  1. Steve Kennedy

    I have a concrete floor/fiberglass wall pool. After I’ve done the acid/tsp/sand steps can I use the same paint on the fiberglass as I do the concrete? And if so what should I use?

    • Yes, you can use the same paint. Epoxy is best, longest lasting. Be sure that the pool is very clean and very dry, and paint on a cool morning or evening, with a good weather forecast ahead.

  2. Steve Kennedy

    So what order do I take the fiberglass walls to include a sanding to prep for paint?? My thought was acid-tsp-sand-acid? Or is there a different preferred order

  3. Johan bday Berg

    Please advise procedure to paint and repair a fiberglass revamped pool from marble lite where the fiberglass started coming of at various places. Contractor did not prepare surface properly before fibreglassing

  4. Steve Kennedy

    Awesome article and very helpful as I’m about to embark on this same project. One question as I have a concrete bottom, fiberglass wall pool which has glass tiles on the water line. How to I address replacing, covering, these? They are old and falling off. I don’t have to retile but not sure how to address this part of the rehab. Any help?

    • Hi Steve, the tiles were glued onto the wall, perhaps with silicone. If you want to remove them, use a scraper and go to town – for power you can rent an air powered tool to do the job, or if they are very loose you may not need, then you will want to remove any adhesive residue, with scrapers / sanders.

      • Steve Kennedy

        After removed are there any other options other than replacing with new tiles? I ask because where they are seated is indented into the fiberglass so they sit flush with the rest of the wall.

        • Ohhh, no I think not. Tile would be the best option. You can find some tile that would be less expensive than the glass tile, just be sure that it is ‘Frost Free’ tile that is used on pools, for the outdoors. Check NPT, national pool tile, or even local tile suppliers, or pool supply distributors in your area. Might cost just $250 or so.

          • Steve Kennedy

            This article is awesome. My last question is what’s the process to refinish the concrete pool bottom correctly??

          • Hi Steve, the prep process is the same, just be sure the floor is cleaned very well with TSP (to remove [invisible] grease/oil) and with acid (to remove [invisible] scale, and to etch the surface, then allowed to dry thoroughly before painting (unless painting with Acrylic, water-based pool paint). Here’s another blog for you: https://blog.intheswim.com/swimming-pool-re-painting-tips/

  5. Alan,
    I have a 30yr old fiberglass pool that was painted with a high build 2 part epoxy paint 4yrs ago and the paint is chalking bad. You touch the pool and turn in to a smurf. I have started to sand it back down to the original gelcoat used 40 grit because I’m impatient now since I previously painted it. Do I have to go that far? Unfortunately some fibers can be seen but not exposed and hair cracks . Should I use the gunite primer and super epoxy paint? What’s the dry time on the paint and primer?

    • Hi Ryan, no need to sand it all off, but don’t skip the TSP and Acid Wash treatment. Primer has an advantage of being able to paint on a moist surface, so it saves several days of dry time, and is a bit cheaper than the paint, I believe. Most chalking of painted pools is a result of low alkalinity, low calcium hardness and low pH levels, perhaps coupled with high chlorine levels. This time around, get a good test kit like the K-2005 by Taylor, and you can control the chemistry more easily.

  6. I have a fiberglass swim spa, which was coated with Gel Coat, and some kind of a finish (that is my question) I then painted the finish which I think was a two part epoxy but I’m not sure, and I wasn’t aware of the issues of non compatibility of the two kinds of paint. That paint peeled off in some places and became unsightly. I then went to my pool supplier and they sold me Olympic paint, and it also peeled, beginning with the indentations in the finish. I presumed that was due to poor application, but it might have been a compatibility issue. So I have sanded off the entire finish, down to coat some kind of finish, but not exposing fibers. I am still working on that effort complete to the best of my ability. Epoxy is not my first choice, because it has to be applied in a beat the clock challenge. I need to determine what paint to use next, and I never want to sand this surface again. Should I test paint samples to determine what they were? Or is there a way to sand and chemically wash the surface and re-coat? I appreciate your help. My son in law insists that i need to remove all finish down to the fiber glass, and then begin anew, since the gel cote is probably corrupted with oils and other material which will inhibit adhesion. Is the Acid TSP Acid protocol enough to clean the finish? There are striations in the finish that remains due to using 36 grit sand paper, should those be sanded smooth? Or to be sure do I media blast the finish down to the fiber and re gel cote? I need some advice.

    • Hi, the peeling paint was most likely the result of grease/oil or scale on the surface. Maybe the acid/tsp/acid process was not followed, and/or the fiberglass not sanded, or the surface still moist before painting. Fiberglass pools will readily bond with epoxy paint (my recommendation), with the Acid/TSP/Acid, followed or preceded by, a sanding of the surface. You do not need to get down to the fibers, and do not need to remove the gel coat, just rough it up for better adhesion, and to remove the glaze. Sanding need not be super-rough, just a slight dulling of the surface. So get the surface really clean, then really dry, and paint it fast after 3-4 dry days, with good weather in forecast.

  7. Hi i am getting ready to paint my fiberglass pool for the first time.The pool has the original gel coat.Two questions one i thought that primer also provided a good adhesion for epoxy or any product.Two i would like to sand the pool with a electric sander not orbital but parallel any issues with that do you think. I will be painting with epoxy Thanks Mark

    • Hi Mark, yes the primer is intended to improve bond to the fiberglass and bond to a second coat. We do recommend using https://www.intheswim.com/p/gunite-primer the Gunite Primer (not the Epoxy primer) as a Primer for Fiberglass. You can use a sander, a belt sander I call them a vibratory sander, sure no problem, perfect for the job. Wear a mask!

  8. Liam Dempsey

    Hello, I have a concrete floor fiberglass wall pool. The floor has been painted previously using an epoxy paint (I have done it myself twice in the last 14 years). However the walls have never been painted, should I use a primer on the walls or can I just acid wash and TSP application on the walls? BTW the walls are white and the floor is blue.

    • Hi, iI am familiar with your type of pool. You can paint the walls – yes. Same prep process as for the concrete, Acid wash – TSP wash – Acid wash… but also do a light sanding of the surface before painting. A primer is not necessary if well prepped, just go with epoxy, 2 coats if you can swing it. Another cool option is to tile the walls with sheet tile 12″x12″ squares, or just do the top 12″ of the pool wall. Not cheap, but super cool. Affix the tile with silicone, then grout.

      • Kyle Kloc

        I have same type of pool fiberglass walls then concrete bottom, looking to repaint…. but, at the seems of the panels are rust stains and they seemed to have caulked the seams and bottom seam where panels meet concrete safety ledge around the pool. My question is can i just epoxy over everything or rust inhibitive primer at rust spots then prime and paint … also seems to have moisture bubbles behind the panels. Wish i could just send pics… but basically I’m going to acid/tsp/acid wash then rip out loose/ failing sealant at seems apply new sealant after i rust prime rust spots then apply epoxy to fiberglass wall panels (if gunite prime is not needed.) the bottom concrete however i just want to use acrylic due to weather and drytime moisture conditions that come with epoxy prep… Or another option was can i just resurface with “diamond brite sgm quartz” directly over top fiberglass panel portion of pool? Will it adhere properly or is primer needed? and then acrylic
        paint bottom concrete half? I’m a journeyman painter so I’m skilled with prep and painting, patching different surfaces just not a submerged pool surface…. just wat to know the proper procedure and which option would be better.
        Thanks for your time

        • Hi Kyle, you seem to have a good plan, with exception to the diamond brite, that stuff hardly sticks on plaster, I’d be surprised if it lasted very long on fiberglass, it might not even stick at all. For the rust, that’s unusual. Not sure where it is coming from, but I would prime it, if you have an anti rust primer that can be used under epoxy. I don’t normally see rust from the seams, but maybe it is dripping down from a steel coping rim? Moisture bubbles, not much you can do there, except sand them down, but that may weaken the wall…?

  9. I am also ready to paint my 39 year old fiberglass pool that I have previously painted twice before with the first time lasting about 7-8 years & the second time only lasted 2-3 years. I used a competitors paint & I want to try your Super Epoxy this time(due to excellent reviews). I was always told that I did not want to put 2)coats of Epoxy Paint. The first repaint I used a primer & 1)coat of epoxy Paint & the 2nd time I used just 1)coat of Epoxy paint. I was advised that since I had used the primer 8 years before, that It would be unnecessary to use the prime again. Obviously not using the primer before the second repaint, probably led to the paint deteriorating in 2-3 years. Would it be overkill to use your $80 Primer & then 2)coats of Super Epoxy Paint or should I just use 1)coat of each-Epoxy Primer & Super Epoxy Paint? I appreciate your comments…

    • Hi – not sure that not using primer was the cause for the shorter lifespan of the second painting. Could have been surface conditions, moisture, or water balance, or paint quality. I don’t think it is necessary to use primer when going over (on top of) epoxy paint. The one thing that Primer is good for is that you can go over a moist surface with the Epoxy Primer, it doesn’t need to be absolutely dry. I think I would suggest just two coats of Super Epoxy, over top of a well-prepped TSP/Acid/TSP, and then sanded surface. Or if you want to use primer, then just one coat of Epoxy on top of the primer. OH, just noticed you have a fiberglass pool – the correct primer for Fiberglass is not our Epoxy Primer, but our Gunite Primer.

  10. Dianne Johnson

    I am pressure washing the loose paint and in some areas down to the fiberglass (?or gel coat?). Can I leave paint if I send the chipped areas? I am going to make a few fiberglass repairs- would they need to be covered in primer or can I just paint over? I was you,g to use 2 coats of paint and no primer. But if I need to prime fiberglass repairs. And there are a few areas where the deep end starts that the paint flaps. Don’t know if I need to cut out or tape over and paint. Thank you!! Dianne east palatka, florida

    • HI Dianne, if the paint is securely attached or bonded well, you do not need to remove it, sanding the edges will hide the ridge so that it’s not so visible beneath the new paint. You don’t have to prime, you can just use the paint as a primer, especially for small areas. You say the paint flaps in the deep end? I don’t understand, but if you mean flakes, or areas that are peeling or areas that have bubbled up and are not attached to the floor or wall, these should be cut out or peeled off until it peels no more, and the edges sanded. Be sure to acid wash and TSP wash the pool thoroughly in addition to sanding the entire surface, and allowing it to dry completely, before painting.

  11. Hello, I am painting a fiberglass pool. I have ordered the Super Poxy Shield Epoxy Pool Paint. I have enough to do two coats on my pool as the article states. I did not order primer with the paint. Did you have long-lasting results without the use of a primer or should I hold the job until I order some?

    • To be honest, I never used primer. The big advantage to primer would be for very rough or porous surfaces, because it’s a bit thicker, and a bit cheaper per gallon. It’s the same reason home painters might use a primer first on bare drywall, and then another coat of more expensive, easier to work with paint as a top coat. You’ll be fine without a primer, it’s not really about longevity, but cheaper cost/better filler for rough surfaces (think ‘cinder block’ surface).

  12. Alan Fischer

    Hello,
    I have a fiberglass pool that will need painted.
    Should I have any concerns that the pool will lift up once the water in drained from the pool?
    I have a friend that is warning me to have the pool anchoraged down to the concrete.
    Please let me know, thanks Alan

    • Hi Alan, there is a risk, yes, if the soil shifts or the water table is high, hydrostatic pressure could lift the pool, but it is rare. If your pool sits topographically higher than the surrounding area, or you don’t have issues with a high water table, the risk is less. Again it is rare, and does not normally happen. But you should watch the weather before draining, (no rain in forecast), drain during a dry period, and work fast so you can fill again asap. Also, pump the water far away or into a storm drain, so it won’t cycle under the pool. I am not familiar with a method to anchor the pool down.

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