8 Top Tips for Swimming Pool Resurfacing
A swimming pool is exposed to a whole lot of stuff that prematurely ages even the most durable materials. Pool chemicals, salts, sunlight, UV, bacteria, algae and mechanical wear on walking surfaces and from creepy crawlies all take their toll. No pool surface is immune to degradation and eventual failure.
If you are reading this post chances are that you have a pool looks quite tired and faded out or even worse has pits, blisters or leaks. Here are some tips for making sure your resurfacing job gives you the look and durability that you are after.
Don’t turn your pool into a boat
A pool, by design, is completely water proof. Its purpose is to contain water for you to enjoy. It stops water from draining away into the ground, but it also stops ground water from entering your pool. When you empty your pool ground water can exert pressure under your pool and lift it out of the ground. Even concrete pools can shift if the water table is high enough. Once a pool is lifted sand can cave into the void and it’s close to impossible to get it back to how it was without major excavations.
Some pools are fitted with a hydrostatic valve. This is a valve or bung in the deepest part of the pool that can be opened during draining to allow ground water to pass into the pool. This makes sure your boat; I mean pool, stays sunk. During resurfacing you can connect a hose and pump to this opening and continuously ‘dewater’ the ground under the pool.
If you don’t have a hydrostatic valve you need to either verify that the height of your water table is lower than the bottom of the pool, or wait until the hotter summer months when the water table is likely to be at its lowest.
Fiberglass is flexible
If your pool has a concrete shell, relax for a minute and I’ll see you again at #3.
In the case of fiberglass pools the weight of water not only stops the pool from floating but also creates an internal force on the shell to ensure the pool retains its shape despite the external forces exerted by the dirt the shell is buried in. Before a fiberglass pool is emptied it is best practice to install internal props to stop the sides flexing inwards.
If the sides of the pool flex dirt can cave down into the void and excavations will be required to get the shell back into its natural position. In extreme situations the forces exerted are sufficient to crack the fiberglass shell and costly fiberglass repairs are required on top of excavation works to rectify the problem.
He who fails to prepare prepares to fail
Preparation is the key to a successful pool resurfacing job. The existing pool shell needs to be thoroughly cleaned. Typically a degreaser or detergent wash is required to remove years’ worth of dirt, and oils. This is then followed up with an acid wash to remove salts and scales. Finally a treatment with a biocide is recommended to kill and inhibit future growth of algae spores and other bacteria.
If there are any flaws in the surface these need to be repaired at this stage. Pock marks, cracks, gouges and bubbles will not be filled up just by the new surface coatings. In fact the new glossy surface will make these existing surface imperfections more noticeable.
Not all coatings are created equal
There are a number of different suppliers of epoxy coatings and none of them are going to tell you that their competition has a better product than them. Some important things to look at when determining quality are:
- What is the coverage per kit? This will enable you to determine how much you will need and therefore what your total material requirements for the job will be.
- How many coats are required? Multiple coats are usually the norm. These need to be considered for total material costs and scheduling of time to complete the job as each coat typically needs 24 hours before the next can be applied. The number of coats also will give you an indication of the film thickness
- What is the film thickness per coat? If the preparation work has been done correctly the only common form of coating failure is that it will wear out over time. Therefore getting a strong thick build of epoxy on the surface will give you a much longer service life. The final surface should be built to greater than 300 micron. If your epoxy supplier recommends only 2 coats but the film thickness per coat is less than 150 micron you should apply additional coats or consider another supplier.
- What are the percentage solids? To enable the epoxy to flow, and thereby be able to be applied evenly, some volatile components are in the epoxy kits. As the epoxy cures these volatile components gas off into the atmosphere. What are left on the pool surface are just the solids in the epoxy. Therefore the higher the % solids the more material you are getting for your dollar. Another benefit of higher percentage solids products is that they are generally safer and easier to work with as there are less volatile vapours for you to breathe in while applying the product.
- Do they offer a warranty? Many suppliers won’t offer a warranty on pool coatings. This is understandable as failures are most likely due to poor preparation and/or application, rather than anything inherently wrong with their product. In the event of a warranty claim it would be difficult to determine whether the coating or the person who applied it is to blame. Some suppliers offer up to 5 year warranties if application is done by an approved contractor. Even if you are going to do the resurfacing yourself, and therefore not qualify for a warranty, this should give peace of mind that the product itself is worthy of a warranty.
Keep an eye on the sky
Consider the weather during planning and application phases of your project. Epoxies need time and temperature to cure.
In most cases if the temperature drops below 10 degrees C they will stop curing. Low overnight temperatures may therefore increase the time required between coats or after the final coat before the pool can be filled. While the epoxies are curing it is essential that they don’t get wet. At best the water will
discolour the coating; at worst it will affect the epoxies integrity. Even high humidity should be avoided as this can be enough to cause problems.
Therefore the best time to resurface a pool is in summer, or at least when the minimum temperatures are above 10 deg C and there is no rain forecast or expected for about a week.
More is more
We’ve touched on this a little in the previous point. Building a nice thick coating is essential if you want your new pool surface to stand the test of time.
A final film thickness of at least 300 micron is recommended for the entire surface. A higher thickness is recommended in areas of high wear such as steps, ledges and shallow end floors. This can be accomplished by an additional coat or by more liberal application as you go.
If doing an extra coat, consider doing it as a partial first coat; that way your final coat will be one continuous coating that will leave you with the best final finish.
Patience is a virtue
When the final coat goes down the pool will look so fantastic you will want to fill it up and start using it asap. Please exercise restraint and follow the manufacturer’s recommendations in regards to curing times.
Typically the pool will need to be left empty for at least a week after the final coat. If the pool is filled before the epoxy has sufficient time to cure you will affect the service life of the coating. Premature fading, chalking and accelerated wear are all likely to be experienced in such circumstances.
With good chemistry great things happen
Your new pool surface will not last forever, but, if you look after it you will get many years of service from it. Up to 12 years is possible for epoxy coated pools under the right conditions. UV from the sun cannot be avoided but it can be reduced by keeping the pool covered when not in use.
Keeping good pool chemistry will prevent chemical conditions that can prematurely degrade your pool surface. If, like most, the only chemistry you are interested in involves human relationships then hire someone to maintain your pool for you. If, like me, you love chemistry then below are some parameters and rules of thumb that will provide guidance for maintaining your pool.
Whatever your preference, may your chemistry be excellent and may you have many trouble free years of enjoyment from your new pool surface.
- pH 7.4 - 7.8;
- Temperature 5 – 35 degrees C;
- Total Alkalinity 80-120 ppm (minimum) to 160 -180 ppm maximum;
- Chlorine levels 2 – 3 ppm;
- Calcium Hardness should be closely monitored and kept within 270 – 330 ppm;
- Regularly clean your pool to remove dirt and slime;
- Pool chemicals need to be correctly mixed and not just dumped into pool;
- The pool should be kept full at all times;
- If using a Cu/Ag system monitor and keep ion concentration low to prevent staining.