Painting the Pool vs. Plastering the Pool

pool-surface-desicion-purchased thru PresenterMediaOne day you must make a decision. The pool plaster has been looking worse every season. Delaminations, stains, cracks, and generally dull and lifeless.

You’ve read of the new types of pool plaster options available (in my previous post), and had started looking into prices for resurfacing your plaster pool – when it hits you – what if I painted the pool?

Painting pools has been an option even before pool plastering came around. Back in the day, all pools were painted; it was an annual pool opening tradition. When plaster for pools began to be used, pool owners appreciated the long lasting and durable surface and the smooth white finish.

So – let them fight it out! Cage Match! Paint vs. Plaster – who will win? You decide, I’ll just lay out the facts ~ as I see ’em, and let you decide. Should you paint the pool, or replaster the pool?

Longevity Factor:

stick_figure_boxer - purchased from PresenterMediaPool plaster will most certainly take this round. Pool plaster, when properly mixed, applied, cured and maintained – can last 15-20 years. Pool Paint? Depending on the type of paint used, as well as application and curing factors, 2-7 years of life can be expected from a pool paint job. Round 1 goes to the scrappy young fighter’s scorecard – pool plaster wins!

Durability Factor:

stick_figure_boxer - purchased from PresenterMediaPaints used for pools, spas and fountains, are specifically made for underwater use, and are quite durable against poor water chemistry, temperature extremes and even rough treatment from pool equipment. Plaster however, with it’s usual 1/2 inch thickness, can handle more distress than the thin layer of pool paint. Plaster wins again!

Prep Work Factor:

stick_figure_boxer - purchased from PresenterMediaBoth pool paint and pool plaster require that the pool be drained properly and prepared for the new surface.

To paint the pool, you’ll need to degrease the surface with TSP, then acid etch the plaster, followed by another washing and scrubbing with TSP. For acrylic pool paints, the pool can be painted damp, but for epoxy paints (the longest lasting pool paint), you’ll need to let the pool air dry for 3-5 days before painting. Tape off the parts you don’t want to paint, and you’re ready to begin.

Pool plaster requires a much more industrial prep process. After draining, the “cut-n-chip” crew arrives, and with tiny saws, they cut the plaster beneath the tile and around all of the wall and floor fittings. Another crew arrives to acid etch the pool, to roughen the plaster surface, which helps the bond of the new plaster coat. Some plaster companies will make a third trip to apply a “scratch coat” – a rough, textured bond coat that adheres tightly to the old plaster surface, while giving a good surface for the new plaster coat to bond to.

Ding! This round goes to pool paint, which has much easier prep work.

Application Factor:

stick_figure_boxer - purchased from PresenterMediaOnce a pool is prepped and ready for paint, the pool painting process is fairly simple. Mix up your pool paint thoroughly and start rolling it on the deep end wall with a 3/8″ nap roller, with a low nap. A 5-gallon bucket with a paint screen is best to move around with, as paint trays tend to spill. Using long, even strokes, apply the first coat, working from the deep end to the shallow end (don’t paint yourself in!). After 4-6 hours, a second coat can be applied, which will require about half of the paint needed on the first coat. Dry time will vary, depending on the paint and outside temperature. Two to five days later, you can fill up the pool.

When pool plaster day arrives, a crew of 4-6 guys will arrive with a large plastering “rig”, or a truck specifically designed for this purpose. One guy remains on the rig, and he mixes up the plaster mix; a mixture of white portland cement and marble dust. Additives for strength or color can be added to the mix at this time.

When ready, the mixer pumps the plaster mix through a thick hose, and the hose man sprays down sections of the pool for the plasterers to begin. With spiked shoes and a bullnosed trowel in each hand, they begin the process of smoothing the plaster evenly over the surface. They need to be careful not to overtrowel the mixture or to delay too long before troweling it smooth.

After 3-4 hours (these guys are fast), your pool will be plastered and a sock is wrapped around a garden hose left in the deep end of the pool. With the hose turned on, the pool begins to fill, without stopping, until the pool is full. You will be left with instructions to care for the water chemistry, and asked to brush the pool twice daily for two weeks, or until the plaster dust is eliminated.

Ding! Round 4 was won on points – by pool paint. If for no other reason than it’s DIY, and pool owner friendly. Anyone can paint a pool. Pool plastering is not something that you should try at home, kids.

Appearance Factor:

stick_figure_boxer - purchased from PresenterMediaBoth new plaster and new paint are looking good! Pool paint is shiny and reflective, and new plaster has a deep luster, like an eggshell. Of course, you can add colors and additives to plaster to create custom tones. You can do the same with paint, and could even paint a mural. Plaster may look the best for longer, but at least initially, and for the first few years, the appearance of both is fairly equal. Round 5 ends in a tie.

Cost Factor:

stick_figure_boxer - purchased from PresenterMediaThe cost of pool plastering starts at 4 thousand dollars, and can be much more if you choose strength additives and pebble or quartz surfaces. Price can be higher in some metro areas, and of course, for larger pools.

intheswim-pool-paintPool paint is one of the most expensive paints I’ve seen, ranging from $50-100 per gallon. Depending on your size of pool, you may need 6-10 gallons, plus some painting supplies. If you paint the pool yourself, you will probably spend $800-900 on materials for the job.

It seems that pool paint may deliver a crushing blow on the cost factor – $1000 vs $5000 – it’s a no-brainer! But remember, pool plaster can last 3-4 times longer than pool paint! If paint lasts, say 5 years, and pool plaster lasts 20 years – they are almost equal in cost. In the long run, yes – but you can never be sure how long it will last, due to the …

Failure Factor:

stick_figure_boxer - purchased from PresenterMediaBack when I was painting pools, we were very careful to prep pools properly and diligently. Nonetheless, about one out of ten paint jobs went bad. Soon after painting, we’d have blisters, or peeling and flaking paint. The result of a bad bond, or bad paint, or too much moisture in the air – never quite sure. But, the fact remains, not every paint job will be a success, and some might even fail miserably.

Plaster jobs can fail too – small and big, there are lots of different problems that can occur with pool plaster. Spot etching, where pits and pockmarks occur. Delaminations, where large sections fall off the wall, or lift up from the floor – bond failure. Depending on the mix ratios, application temperature and speed, curing, and chemical care after the plaster job – you may see variations in hue, streaking, or trowel burn. I have had almost an equal number (1 in 10) plaster jobs that have some serious defects, some to the point where we have had to replaster the pool, to keep the customer happy.

Round 7 – ends in a tie. Both pool paint and pool plaster can fail. But that won’t happen to you, I’m almost sure of it!

The judges are confounded; two rounds went to plaster, two rounds went to paint, and 2 (or 3?) rounds ended in a tie. They are calling on you to score each round for points. Who wins, Pool Paint or Pool Plaster? You decide.

Davy Merino
InTheSwim Blog Editor


Painting the Pool vs. Plastering the Pool — 42 Comments

  1. I think you do a great job answering questions!! I have a old plaster pool with many wide (but not deep) plaster chips all about the size of a normal paper plate. Currently, I am considering epoxy painting. My question is about patching the large chips.Should I plaster and if so what product and process. If no then is there any new or special prep work for these areas or is it the same for the entire pool?

    • Hi Christopher, you could just paint over them, since it’s also plaster, just the previous layer of plaster. We call these areas ‘delaminations’ or ‘pop-offs’, and they are places where the new plaster did not bond well to the old plaster, due to sloppy replaster prep practices, or mix and application problems, or curing problems. And since you have some, you probably have more. And some of the area around the existing pop-offs may also be delaminated, and could pop off after painting, which you want to avoid of course. If you pressure wash the pool with a 2 500 psi machine, you can likely break loose any other hollow spots, and will be able to hear hollow spots when you pass over with water. Another method is to drag a pole or chain around the floor to listen for hollow spots. So, to answer your question, the prep would be the same, but put effort into locating additional spots before prepping for paint. If you want to fill them, it’s not hard, just mix water, bonding additive (like Acryl 60) and Pool Plaster mix, like our EZ Patch 1 product, to a creamy consistency and spread it with a trowel. Then, since you are not refilling it right away with water, you would want to cover the areas with wet burlap, kept wet for several weeks, to allow the plaster to cure without shrinking and cracking, also need some good temps, 45-85 degrees, to get a good setup. So you couldn’t just patch with plaster and then paint, the plaster will need to cure for 1-3 weeks, depending on temperatures.

  2. is it possible to not use plaster but to mix a portland cement and a sand mixture to stucco the concrete in the pool. I am building one in Nicaragua and it is pretty expensive to use plaster.
    thoughts. I was thinking of the cement sand mix and paint that.

    • Hi Matt, a cement/sand mix is often used beneath vinyl liner pools. It can be very strong, but doesn’t have the same waterproofing properties as a pozzolon modified plaster. But even basic plaster is just white portland cement and marble dust, which is a form of silica, so not so far from grey portland cement and (fine) sand. I suppose you could do it, and if you plan to paint anyway, it doesn’t matter the color or aggregate used I suppose.

  3. Is there a difference in the terminology of ‘gunnite’ and plaster? Based on the fact that my pool has been painted in the past, I am going to opt to paint again. The painting part seems simple enough, but the prep work seems a little daunting. Can you give more specific instructions and tips/cure times on TSP, Acid Etch, and then another round of TSP? Also, what should I look for in terms of doing some plaster patch? If I am down to the concrete in certain areas, can I just paint over that, or should I lay down some plaster? Thanks-

    • HI Scott, most concrete pools are formed with a shell of Gunite, or Shotcrete, same thing. The waterproof coating on the top is called plaster or whitecoat, or marcite, all same thing. So a plaster and gunite pool is also… same thing. To prep a plaster pool, start with mixing 1 lb of TSP into 4-5 gallons of hot water, pour onto the walls using a flower watering can, and scrub well, especially around water line areas. Pour onto the floor and also scrub. Do it well on steps and around the drain and shallow floor. TSP is a degreaser, and that’s the goal, to remove oils and greasy deposits. Hose it all clean, very well, and pump out all water (Tip: always start around the main drain first, because it quickly fills with water). Then mix a 50:50 acid/water mix (always add acid to water, not water to acid), in your flower watering can, and after pouring the drain area, lightly scrubbing then rinsing heavily, pour the steps, scrub and rinse heavily, pour the walls, scrub lightly and hose heavily, then the floor. Do sections at a time, as much as you can do in one minute. Rinse before 60 seconds is up, to not overburn the plaster. After acid washing everything, rinse again well, and pump out all waste water, after neutralizing with 1.5 lbs of pH up for each gallon of acid used. Then, to neutralize acid and make sure all grease is gone, including new grease just blown in, or tracked in, TSP wash the pool again, rinse well, and pump dry. You can do each step back to back, no dry time in between. Then let the pool sit dry for 3-5 days. If it rains, get down there and pump out any water. Try to keep the pool clean and dry. Then after checking the weather for 3-5 clear days ahead, paint the pool, 2 coats, in the morning while it’s cool. Use masking tape to tape off the tile line and anything else you don’t want painted 😉 – You can patch the plaster first, but it should be cured for at least a week, underwater, if not 30 days, so there is no trapped moisture there.

    • Thanks! Just to confirm, if I do plaster repair, cure it underwater for 1-4 weeks before moving forward with cleaning and painting? Bad idea just to paint over thinner areas where just cement might be exposed?

      • Hi Scott, not a bad idea to paint over thin areas, the paint will smooth over any rough spots, and become a waterproof coating, to protect the (not necessarily waterproof) gunite shell. Actually, it may be better not to patch the plaster, because, if the patch doesn’t stick hard and fast, it may pop-off in the future. Plaster should be at least 3/8″ thick to stick well. Now I’m thinking, if the areas we are speaking of are thin and small, maybe it’s better just to paint over them. If they are deep and wide, and trap dirt and algae, or look awful, then patching could be done. either way…

    • So my guy wants to use Poxolon 2, but says first coat would be the ‘primer’ coat’. In other words, not using any other product as a base or prime layer. Any thoughts on that or that product? He also mentioned ‘Aquabrite’, which is 3 times the cost, but is supposedly more durable. Similar to plaster in that they will have to remove all the old paint before application. Any experience with it?

      • Hi Scott, Poxolon 2 is a good quality paint, but Olympic recommends “using the same type coating to recoat a previously finished pool. This assures the best possible adhesion between old and new. ” He may have some prep secret that will ensure a good bond, but I don’t know of one. I think I would ask for a guarantee against any ‘bond failure’ on those areas for 5 years, if I was you. Or sandblast the rest of it, or buy a can of the conversion stuff, and ask him to use it first, before the primer coat. Aquabrite is like a very thin plaster coating. I don’t think it is worth the extra cost in my mind, and for that you definitely would need to sandblast. It’s only like 1/16″ thick, so it’s almost like paint, and subject to delamination or bond failure, just the same.

  4. Hi Davy. Thanks for the great information. We are having our pool replastered, and the man doing said it is fine to do it now, at the end of the season (mid-September), as long as we maintain the pH and brush the pool for two weeks, then close it properly. In the meantime, somebody working at a pool store said this is the absolute worst time to replaster, and we would have etching when we open it in the spring. So now I’m wondering, should we hold off until spring? The pool is already empty, so we’ll need to refill it either way, but I still have time to delay this until spring if that will be much better. Thanks for your help!

    • Hi, I think I would also wait, unless given a discount incentive to do it now, and some guarantees that certain problems like etching, or more specifically scaling will not result. New plaster always has a rising pH for about 4-6 months. If it was closed just a month after plaster, and the pH is not monitored thru the winter, it could become very high, which could cause minerals to drop out of solution and scale on the surface, in crystals, esp. if calcium hardness levels were high or if the plaster was still shedding ‘dust’. Your plasterer may do an acid start procedure, or do winter checks, or have some other method to maintain proper pH during winter, and if so – then it would be ok to do it now, perhaps even preferable to leaving unplastered gunite filled all winter. But if he says ‘naah, don’t worry about all that stuff, it’ll be fine!’ – run for the hills! 🙂

  5. You forgot to mention one advantage of paint…. the ability to change the color of the pool at a reasonable cost as a DIY job….

    That is one more point for PAINT making it the winner over plaster.

  6. hi Davy:

    I am using a cold water power washer to clean my empty pool. I bought TSP before I realized it cannot be used w/the power washer I bought. Can you recommend a cleaning agent that will not hurt the PW or my sump pump?

  7. I found after emptying my pool that there is about a 4 by 2-inch hole about one 16th inch deep where the plaster is missing. I got a pool plaster repair kit and also some epoxy. Which is the best to use?

    • Hi Tom, that sounds like a plaster delamination, or ‘pop-off’, Clean the area well to remove grease and oil, then acid wash the surface, and then rinse very well. then mix the plaster mix and cover it smooth. Place some wet burlap over it for curing, unless you can fill the pool quickly again. Test around the delam area, by tapping, more may be hollow – and the pop off may be larger than it currently is. Best to remove all loose material, even if your patch ends up being 3x the size.

  8. I need help! I just had my 12x 24 inground pool supposedly destained by a pool company! They used muriatic acid and power washed the entire pool, yes, they did empty it first. It was supposed to make it look ” like new” again, NOT! The surface of the pool is quartz, would I still be able to have it painted over that? Also, do I need to have it acid washed again or just use TSP as recommended and then paint? There are no defects but it looks ugly which brings me to the reason I would like it done. Can you help me, what would an approximate cost be and are there any recommendations?

    • Hi Kathy, An acid wash is supposed to remove a thin layer of the plaster coating, exposing fresh, unstained plaster beneath the surface. Just 1-2 mm of plaster is usually removed. Now, if they did not do it right, with a weak mix, or lack of process, they may not get the results promised. I wonder what their response would be – maybe they can try again? for Free? Or offer some explanation why the appearance did not improve. An opposite problem can occur if a pool is acid washed much too aggressively, which can etch and roughen the surface, and expose gunite (concrete) beneath the pool plaster. Now for painting, if you wanted to paint, that is not without it’s own set of problems (only lasts 5-7 years at best, and can sometimes fail, if prep, mix, application, drying, weather and other stuff is not planned properly). But, yes it can be painted, and you could skip the acid wash part, which is meant to roughen the surface and remove scaling (assuming they did it correctly). The TSP part of paint prep is to degrease the surface, very important step – use hot water with TSP and scrub every inch of the pool, and then hose completely and thoroughly. Then allow the pool to dry, following paint can instructions, before painting (on a cool morning, 60-80 degrees, with no rain in the forecast).

  9. how do i know if my pool is a plaster or painted pool? it’s made of concrete and has a very thin chipping layer so i assumed painted. i want to paint it and was just thinking of power washing it prior would this work?

    • Hi Yazad, if you can peel off or chip off paint chips, as opposed to chunks of cementitious plaster – then it’s painted. I suppose it can be hard to tell, but look closely, perhaps under a microscope (if you have one), and it should be evident, if a 1 mm layer of paint is covering the plaster, or bare concrete. Power washing would be a good idea to remove loose paint, but a TSP wash and Acid wash is also needed, to degrease and etch the surfaces, respectively. The paint can labels have good instructions on exact prep and application. Follow those instructions, and with good dry weather, you should be golden (good).

    • Hi Peggy, no it doesn’t matter, but most people do paint in the spring, but end of season may be less stormy, less rain. I’d do it before leaves start to fall, and when daily high temps are 65-80 degrees F. Cool, dry mornings are best. Worst time of year to paint a pool is during very wet periods, or very hot (or very cold) periods.

  10. My pool painted approximately 9 years ago with (epoxy paint)
    Now I would like to renovate my pool with plaster change coping and place tile. The contractor said in order to remove old epoxy paint they need to use wet sand blast. I know this is expensive will cost me almost $3000. Should I go with sand blast or there is another way how to remove old epoxy paint.
    Please advise.
    Thanks Victor.

    • Hi Victor, that is correct that is the only suitable way to remove the old paint, which must be completely removed before the pool can be replastered. One of the drawbacks of painted pools, is exactly this, if you want to ever revert back to plaster, and stop painting the pool, you will need to sandblast, beadblast, or in some cases a very strong pressure washing, followed by a strong acid washing may do the job.

    • Hi Peter, yes you can replaster a painted pool, but not first without sandblasting the old paint off completely. This can be done, it just costs more, maybe $3000 more than a regular plaster job…

  11. What’s the best pool plaster mix? I’ve looked at Diamond Brite and wonder if it’s really any better than other pool plasters?

    • Diamond Brite is made from quartz aggregate and polymer modified cements, it is very strong, but much of the strength and durability has more to do with how good the plasterers are, and how thick they apply the plaster, and the quality of the mix, application temperatures, etc. I’ve seen a few DB jobs that were not done right, and failed, due to poor practices or lack of training. A good crew should do any plaster coat correctly, I don’t mean to scare you. Anyway, I would give Diamond Brite a try – if it was not more than 20% of a regular plaster coat. In many cases, it may not be more than 20% more durable than regular plaster – but in others it could be.

  12. I have a very old pool (fiberglass) and the paint in certain areas is gone.
    Can I powerwash, sand it, apply primer (poolpoxy) and then paint?
    I had 2 pool people come out and they both told me not to acid wash, since it would be detrimental for the fiberglass.
    Don’t know what to do.
    Please help!

    • Hi Alex, the purpose of an acid wash is to roughen the surface (very slightly) and to remove scale deposits. But sanding will accomplish the same thing, so yes sanding is an approximation for acid washing, in paint prep. You still should do a TSP wash or other surface degreaser, after sanding

  13. If painting, what do you do with the areas of the pool where the plaster has chipped away? Can you replace the tile features that are embedded in the plaster?

    • Hi, for holes, cracks or divots, you can patch with our Epoxy Patch product, or with plaster patch material, before painting (but after drying/curing of the patch). For the embedded tile, I usually tape over the tile strip, and do not try to paint the grout joints between the small tile pieces. If you have patience however, you can tape over the trim tile, and then come back after the pool paint is dry, and with a small artists brush, paint the grout joints between the trim tile.

    • Hi Vicky, No worries, Rough surfaces will use more paint for coverage, but it’s not a problem. First time paint jobs also take more paint than recoats, because it soaks in just a bit. Painting a rough surface will also serve to smooth the surfaces, as it fills in some of the pitted areas, and softens edges.

    • Hi, the longest lasting paint is definitely Epoxy pool paint, lifespan up to 7 years. However, if your pool was painted before, it must have been with Epoxy paint. Painting over acrylic or rubber based with epoxy, and it won’t bond properly, chemically speaking, and give you problems. If it has never been painted, no problem, go ahead with epoxy, but if it is a painted pool, find out which type of paint you have rubber, acrylic or epoxy. If you have rubber paint currently, you can use advance conversion paint to convert to epoxy. If Acrylic, like our Aquacoat, then you must use acrylic again, or sand blast it all off – ugh!

  14. Hi, we are looking to we surface our pool. We are looking for the best bang for out buck. The company that came out stated that plaster only lasts about 10 years and should go with granite finish, almost twice as much, that will last 20 years. From reading your blog, it seems plaster should be lasting much longer, shouldn’t it? Or is the granite finish the better pick?

    • Granite finish is also plaster, but has added granite aggregate (very small like sand) added to increase durability. However, it is still susceptible to damage from incorrect mix, application or water chemistry. It probably will be more durable, but wont’ necessarily last twice as long. The key to plaster life is good water chemistry (and a good initial plaster mix, and application, and curing, etc). Plaster can last 20 years, sure – but many replace it sooner – for aesthetic reasons, although an acid wash can improve appearance. Plaster is the waterproof coating over the gunite/concrete – it takes decades before it wears thin enough to expose the gunite, and actually NEEDS to be replaced.

  15. This artical was a great hlep. Questuion I use a polaris 3 wheeled pool sweep If i chooes pait will that be a problem?

    • Hi Gordon, that’s a good question. My first reaction is that using any automatic pool cleaner may have an effect on the paint, wearing it thin over time. However, if the cleaner is not overused, and limited to say, 1 hour per day of operation, the effect will probably not be noticeable. I’ve painted many pools with auto cleaners of all types, including pressure Polaris cleaners, and never noticed any undue wear. Proper chemistry will also help, as painted pools with acidic water conditions, (low pH and alkalinity) can begin to “chalk”, and an auto cleaner will only accelerate the issue.

  16. Pingback: Painting an In-Ground Swimming Pool | InTheSwim Pool Blog

Leave a Reply

Your email address will not be published. Required fields are marked *