Pool Plaster VS Paint
Concrete swimming pools are the Cadillac of the pool and spa industry and most concrete pool owners are very happy with their luxury pools...except when it comes time to refinish the interior surface of the pool. While a concrete pool may be more luxurious than a vinyl liner pool, vinyl pool owners are laughing when it comes time to coping and liner replacement.
A coping a liner installation in an existing vinyl pool might cost in the range of $4000. If you have a concrete pool you will not likely be so lucky. First, a concrete pool has more components than a vinyl pool. A vinyl pool has an aluminum or PVC coping track that retains the liner bead along the top of the pool wall. A concrete pool coping is very different:
Concrete Pool Coping - Concrete pool "coping" is the area of the pool deck that sits directly on top of the vertical wall of the pool shell.
Perimeter Tile - Most concrete pools have a tile band at the top of the pool wall which helps to protect against staining at the waterline
Interior Surface - The interior surface of a concrete pool is usually a dense mortar or plaster layer with a smooth finish
Where a vinyl pool might need both the coping track and a new liner, a concrete pool may need more than just a new interior surface layer. Renovations and maintenance to concrete pools can be restrictively expensive and as a result many pool owners will look to find a lower cost alternative...and this is where pool painting comes into the discussion. Note that these numbers might not be accurate for your area, as the cost of pool services fluctuates dramatically based on where you are located, but the ratios of the numbers will be mostly consistent.
$1000 - New coping track
$3000 - New vinyl liner
$4000 - Potential vinyl pool renovation cost
$6000 - $10,000 - New cast or poured coping stones
$7000 - $12,000 - New perimeter tile band
$6000 - $10,000 - New pool plaster
$19,000 - $32,000 - Potential concrete pool renovation cost
Fortunately the service life of concrete pool components is fairly long. The interior surface layer of the pool will be the area that requires the most frequent maintenance and renovations. Concrete pool coping and tile bands installed in concrete pools properly should both last for many decades. This means that you will likely need to renovate the interior surface a few times for every coping and tile renovation that you do.
The Truth About Pool Paint
Almost all concrete pool owners will end up looking into the cost of having their pool painted versus applying a new plaster layer. On the surface it might appear that pool painting is a lower cost alternative to plastered interior surfaces - so why do concrete pool experts almost all unanimously agree with the following statement:
"You should never paint a concrete pool"
There are really only two reasons why concrete pool experts would say that you should never paint a concrete pool. The first is that pool plastering is good, profitable work, and something that a home owner can not do themselves without decades of concrete finishing experience. Concrete pool experts might tell you that you should never paint a pool in order to preserve their clientele and preferred work profile. The other reason, and the more likely one, is that they know something that you do not.
You might think that it would be very easy to cost-compare pool plaster versus pool paint however the dynamic nature of the calculation makes it more difficult than you might expect. While a pool paint should cost half as much as a pool plaster, it is in the long run that you will get the short end of the stick. Pool paint is not simply inferior to pool plaster. There are a host of technical reasons why paint can, and most likely will, end up costing you more in the long run.
Pool Plaster VS Paint Cost Comparison
It can be very appealing to pool owners to look towards paint as the cheapest possible interior surface option for their concrete pool. Who has $10,000 to plaster a pool when you could paint that same pool for less than half this amount. Potentially you could do it for even less than this if you endeavor to paint the pool yourself as opposed to hiring a professional. While this might seem like a great cost saving idea, there is more to consider than just applying the new surface layer to the pool.
One of the biggest concerns with pool paint is that once you have painted a pool, you can no longer go back to plaster without first paying to have the entire pool sandblasted. This is an expensive process that is very messy and this will usually cost the pool owner anywhere from $3000 - $6000 depending on your geographic location, as well as the current condition and size of the pool.
Since the pool paint stops water from penetrating the interior surface (at least in theory) this means that a new plaster layer can not be bonded over the old paint. If you ever want to plaster the pool again then you will need to absorb the cost of sandblasting in addition to the new plaster costs.
So what is the problem? Just paint your pool and then always paint your pool to avoid sandblasting costs...right? Wrong. Painting a pool will almost always result in the surface layer of the pool degrading to the point that it is no longer mechanically sound. The real question is how long will it take before this happens.
Pool Plaster - Pool plaster lasts on average between 7 to 12 years before needing to be resurfaced. Pool plaster can be applied over old, existing pool plaster so long as the old layer is not delaminated from the base shell layer. This means that you will get between 15 to 25 years out of only two coats of plaster in your pool. This would put your interior surface costs at around $12,000 to $20,000 over the course of 25 years.
Pool Paint - There are 3 types of concrete pool paint and each of them have differing costs, application requirements, and service life expectations. On average a pool paint will last between 3 - 7 years depending on the type of paint you choose. Acrylic paint has the shortest life of only 2 - 4 years, where epoxy has the longest life of 5 - 7 years. Rubber based paint is somewhere in between these two. This means that if a pool cost around $3000 to $5000 to paint, and to maintain the pool surface for 25 years would take, at best, three or four applications of paint, then your cost to paint your pool for 25 years would be around $12,000 to $17,500.
Right away you can see that the cost of these two interior surface options are much close than you might think. The complication with this calculation is that there are too many variables. Does your pool paint cost you $3000 or $5000? Do you get three years life from your paint or will you get seven or more perhaps? Adjusting these numbers will obviously change the totals of a 25 year cost profile. The point of this comparison is that it is easy to see that painting a pool is not less than half the cost of plaster. Painting a pool is, at least arguably, almost as expensive as plaster...but wait, there's more!
Hidden Costs Of Painting Your Pool
By now what I hope that you are seeing is that it is not as cut-and-dry as you might think when comparing costs of pool plaster versus pool painting. As the above calculation shows, after a 25 year period the costs of the two interior surfaces are actually very close to one another...but there is still more to consider. You should only need to drain and re-plaster a concrete pool around twice in 25 years. To paint your pool you will need to drain and paint at least twice as often. This is additional work, and money, that you will be paying for. Every time you need to drain and refill your pool you will be absorbing additional costs that add up against paint versus plaster in your pool.
The biggest reason that pool painting is just not as good as pool plastering is due to the fact that paint simply does not do a great job of protecting the interior surface of your concrete pool. With a new plaster layer added to your pool, this means that the entire interior surface of the pool is new, and made from new mortar plaster. When you paint a pool, you are applying paint over the same deteriorating concrete surface time and time again. As the pool ages, the interior surface of your pool will degrade and become weaker, as well as starting to crack, chip and delaminate in large chunks. No amount of paint will make aging concrete look or feel perfect again. A painted pool will look nowhere near to as good as a plastered pool over the course of 25 years. Painted pools are rougher, more unsightly, and will have much more damage of the surface layer than a pool that gets new plaster every 7 - 12 years.
The reality of pool paint is that at some point the interior surface of your pool will degrade to the point where you can no longer paint it anymore. Chances are that you will not get 25 years out of the pool before you need to resort to sandblasting. Sandblasting removes the deteriorating surface layer of the interior surface of your pool. This leaves a strong, clean concrete surface to which you can plaster or paint over with confidence that the layers will bond properly. If it were not for the sandblasting costs perhaps pool painting would be more accepted as an option for refinishing concrete pools. Once you factor in the cost of sandblasting then it becomes clear that the costs of painting your pool actually exceed the costs of plastering your pool over time. Not only do you end up paying more for paint in the long run, but for the entire life of the pool you get to enjoy a rough and cosmetically imperfect pool finish.
When To Refinish A Concrete Pool
The reason why concrete pools require an interior surface treatment is to aid with the resistance to water. If a concrete pool did not have a plaster or painted interior surface then the rate at which water would escape the pool would be unacceptable. Further to this, as water absorbs into the concrete of your pool, it causes damage. The more water that is able to absorb, or leech, into your pool shell, the more that the surface layer of concrete will begin to weaken, crack, chip, shale and ultimately fail.
Even interior surfaces in concrete pools are not waterproof - they are water resistant. As the surface of the pool begins to age, whether it is painted or plastered, the rate at which water absorbs into it will increase. A pool can look more or less normal, but be losing water through the interior surface at an advanced rate, which in turn causes even more deterioration and failure of the surface concrete layers. This is the reason that you need to refinish the interior surface of your pool, and often the old surface will still look to be decent, however you can be losing water and potentially causing structural damage to the pool if left for long enough. Much like a vinyl liner in a pool, you are further ahead to replace early as opposed to trying to get every possible day of life from your interior surface. More often than not you will cause additional damage to the pool which is greater than the cost savings you experience by delaying a new interior surface for a few years time.
Pool Plaster - Pool plaster is generally aged according to years however this is not an accurate way to determine how long a plaster will last. Pool plaster is hard troweled to a smooth finish. It is this smooth finish which helps to increase the water resistance of the plaster. A pool plaster should be replaced once this smooth finish has worn away and the plaster is rough to the touch. Once the plaster is rough to the touch this means that the enhanced resistance to water has been lost and water will readily find a path leaching through the plaster layer into the substrate shell. Since pool plaster looks the same whether it is smooth or rough, many pool owners and pool technicians leave the plaster FAR longer than they should. Another common mistake is acid washing pool plaster. Acid washing strips away the cement from the plaster, leaving only the sand aggregate behind along with a rough texture. Acid washing is one of the fastest ways to ruin a pool plaster and typically a pool plaster should only have one or two (very mild) acid washes at most in its life. Acid washing might make pool plaster look really nice and clean, and colors will pop again and stains will disappear...but the plaster will be rough. Once pool plaster is rough to the touch it needs to be replaced.
Pool Paint - Pool paint is not as easy as pool plaster to tell when it is time to refinish. First, there are multiple kinds of pool paint which will all have different service lives and symptoms of failure. Additionally many concrete pool owners will assume pool ownership and not know how old the paint is, or what kind of paint was used prior, which is very significant since different pool paints are NOT compatible. The most common ways to tell if your paint needs to be redone is the painted surfaces will develop a chalky film, or paint will start rubbing off / chipping off from the base concrete layer. It can be very difficult to determine what type of paint was previously used on your pool and using the wrong type of paint is almost certain to be a disaster. The best bet is to send paint chips to the manufacturer that you are looking to purchase your paint from and have them test for you to assure new paint adhesion. This can also be done using a solvent test in the field however the conclusions of this are seldom conclusive enough to base a new interior surface decision off of. Denatured alcohol is a solvent for acrylic paint, acetone is a solvent for most rubber paints, and MEK (Methyl Ethyl Ketone) is a solvent for epoxy based pool paints.
Is It OK To Paint A Pool?
Not really...but so many people do it anyway that it is almost normal now. Painting your pool does not look as good as new plaster, it does not feel as good as new plaster, it requires reapplication at minimum twice as much as new plaster, and when you factor in all associated costs over a long term service cycle, painting your pool actually costs more than new plaster. So why they hell does anyone paint their pool? Two main reasons come to mind:
The DIY Pool Owner - Some people simply do not like to pay for something when they can do it themselves for much less money. The problem with this is there are almost zero pool owners with the ability to actually plaster a swimming pool. It is a skill that no amount of labor can replace and any pool owner trying to plaster their own pool, most likely, is going to make a huge mess of it. Paint on the other hand is very easy to do yourself. Even the more difficult epoxy and rubber paints are still easy enough for the average pool owner to do themselves by following some basic directions. If you are ready, willing and able to paint your own pool then this might be one reason to choose paint over plaster since you will be saving a boatload of money on labor over the next 25 years.
Inaccurate Professional Advice - When a pool owner calls a "pool guy" they seldom think to ask whether this company is experienced with concrete pools. The average pool owner does not understand that the pool industry is very much divided into classes and most pool technicians only work on, and are experienced with, one kind of pool. If you are talking to a pool guy that has never built a concrete pool, and does not have the skill to plaster a concrete pool, what kind of advice do you think they will give? Very often, they tell the pool owner to go with paint because it is cheaper, when in reality they are under qualified to be giving advice on concrete pool interior finishes and are steering the customer towards the only type of work that they can offer the customer. This is also how you end up with concrete pools having a liner hung in them...but that is a story to discuss another day.
Concrete pools that have a new plaster interior surface every ten years or so will almost all age better than concrete pools which are painted regularly. The net result of years of an inferior interior surface will be advanced crazing and cracking of the concrete shell, including the potential for structural cracks. Tile and coping failure are greater on painted pools due to the increased water migration through the shell, and rebar within a painted pool shell will rust and fail far faster than a pool that is replastered often. This damage is even more aggressive should the painted pool also be a salt water pool which would allow the rebar grid to become part of the galvanic couple via the leaching salt water through the surface. Most simply stated, painted pools wear out faster than plastered pools and this is all essentially boils down to the interior surface becoming porous and unstable from water passing through it.
If you have read all of this information and you have considered your options and you would still like to learn more about pool painting then you can read this extensive concrete pool painting guide which talks about the easiest type of pool paint to use. If you do end up painting your own pool then at least you are well informed as to the benefits and potential drawbacks of this process.
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