Pool Plastering: What Swimming Pool Owners Need to Know

Pool plastering is both an art and a science, requiring the right materials, techniques, and maintenance practices to ensure a beautiful, durable finish. Over the past few decades, pool plastering has evolved substantially, incorporating modern materials and techniques to enhance durability and aesthetics. Meticulous attention to detail is critical to success in plastering jobs. In this article we describe what’s important for you to know about pool plaster as a homeowner. We also answer frequently asked questions regarding plastering.

What is Pool Plaster?

Pool plaster is a specialized coating material used to create a smooth finish on the interior surfaces of swimming pools. It is typically applied over the concrete or gunite shell of a pool and serves both functional and aesthetic purposes. Pool plaster creates a barrier that prevents water from seeping into the pool’s structure, while also providing a comfortable surface for swimmers.

Composition and Types of Pool Plaster

Pool plaster is generally made from a mixture of white cement, fine marble dust, and water. This basic mixture, often referred to as white plaster or “marcite”, was the original type of pool plaster. Over time, plaster composition has evolved to incorporate different materials to enhance durability, color, and texture.

By far the most popular type of plaster used in Florida today is the exposed aggregate plaster, commonly known as “quartz plaster”. It’s a mix of plaster and crushed quartz, providing a more durable and stain-resistant surface. It’s available in various colors and offers a sparkling finish from the exposed quartz aggregate.

AQUAVIX Pools is a factory-trained and certified applicator of Diamond Brite exposed aggregate plaster.

The “Diamond Brite” Quartz Plaster

Quartz plaster products are not all the same. There are different levels of quality offered at different price levels. The most prominent quartz plaster product in Florida is SGM’s “Diamond Brite“. It’s truly a superior quartz plaster based on polymer-modified cement and proprietary quartz technology that offers unparalleled fade resistance.

Some pool builders in South Florida avoid Diamond Brite because it costs more and its application is not trivial — it requires special skills, techniques and training. AQUAVIX Pools is a factory-trained and certified applicator of Diamond Brite.

Plaster Color Selection

Color is added to the plaster in two basic ways: (1) using quartz of different colors, and (2) adding pigments or dyes to the base mix to create different hues. In general, we at AQUAVIX Pools prefer non-dyed Diamond Brite types that get their color from the quartz aggregate only. Among them, our favorites are the following:

When choosing the plaster color for your pool, consider the color of your waterline tiles. They should be paired together for a pleasant aesthetic.

Dyed plasters are inherently more prone to staining and discoloration over time. If the pool water chemistry is not kept well balanced, these problems are more likely to occur. Also, the application process for dyed plasters is more labor-intensive and therefore more costly.

With the above in mind, if you really like the looks of a particular dyed plaster, AQUAVIX Pools is an expert applicator and will be more than happy to apply the color of your choice. We have developed our own special techniques to apply dyed plaster that have produced the most amazing finishes, in sharp contrast to the awful results we often see from many other pool builders and pool remodelers.

Our favorite colors among the dyed Diamond Brite plasters are the following:

When choosing the plaster color for your pool, consider the color of your waterline tiles. They should be paired together for a pleasant aesthetic. Also, consider the effect you’re looking for: serene, relaxing, vibrant or bold? In the end, it’s a matter of personal preference — there’s no right or wrong color when it comes to your pool plaster. Only one word of caution: if you have kids, keep in mind that dark colors may create an illusion of depth that may increase the risk of diving accidents.

The Importance of Surface Preparation

Proper surface preparation is crucial to the success and longevity of a pool plastering job.

New Pools

First and foremost, plaster should never be applied to a new concrete pool shell that is less than 28 days old. While some pool builders tend to ignore this fundamental rule, the 28-day period is critical to allow concrete to cure and reach sufficient strength before applying any finishing materials like plaster. Also, fresh concrete contains a significant amount of water that needs time to evaporate as the concrete cures.

Applying plaster too early, before the concrete has adequately cured, can result in a weaker bond between the plaster and the concrete, leading to potential issues over time, including:

• Delamination and Hollow Spots: The plaster may not bond properly to the concrete, leading to areas where the plaster separates from the underlying surface.
• Cracking: The plaster may crack as the concrete continues to shrink during the curing process.
• Staining and Efflorescence: Excess moisture trapped in the concrete can lead to staining and efflorescence (white, powdery deposits on the plaster surface) and plaster discoloration.

Applying plaster too early, before the concrete has adequately cured, can result in a weaker bond between the plaster and the concrete, leading to potential issues over time

After the 28-day curing period, proper surface preparation is essential to ensure a strong bond between the plaster and the concrete. One or two days prior to the application of plaster to a new pool, AQUAVIX Pools will send a crew to thoroughly prepare the concrete pool shell surface. This includes:

• draining of any rain water that may have accumulated in the pool shell
• removal of metal wires left from the shotcrete application
• pressure washing of the pool shell surface to remove any dirt and mud
• acid washing of the pool shell surface to remove any metal residues and improve adherence
• hydraulic cement patching of any imperfections in the concrete

Resurfacing Jobs

Proper surface preparation is crucial when applying new plaster to an existing pool. The success and longevity of the new plaster largely depend on how well the surface is prepared. Unfortunately, not all pool builders take the necessary time and exercise the necessary caution when preparing the surface of an existing pool for new plaster application.

If you’re looking for a pool resurfacing contractor, here’s a useful list of questions to ask any prospective candidate: 12 Questions You Should Ask Before You Choose a Pool Resurfacing Contractor.

The steps involved in a pool resurfacing job are the following:

• Draining. Especially in flood zones in the Florida Keys, Miami, Hollywood and Fort Lauderdale, where groundwater is found at shallow depths, it is extremely important to exercise caution when draining a pool to prevent it from shifting. “Pool popping” is a real thing that happens more often than people think. Older pools generally don’t have hydrostatic relief valves installed in the main drain, so it’s important to unplug the main drain before completely draining the pool.
• Surface inspection. In addition to visual inspection for stains and cracks, the general practice among pool builders is to use a hammer to tap on the entire pool surface to check for hollow spots. A hollow sound indicates areas where the existing plaster has delaminated from the substrate, which will need to be repaired.
• Stain and crack repair. We use a grinder as needed to remove stained spots and cracks on the old plaster surface. The goal is to prevent stains and cracks from propagating to the new plaster. We clean out the cracks and fill them with a pool-grade hydraulic cement specifically designed for underwater applications. We smooth the repair to match the surrounding surface. Note that this applies to cracks on the plaster surface only — not to cracks that penetrate the concrete shell. Shell cracks are indicative of structural issues that need to be investigated and treated separately.
• Removal of old plaster. We use chipping hammers and/or sandblasting equipment to remove any loose, flaking, or delaminated plaster. The goal is to remove any weak or unstable material so that the new plaster can adhere properly. In most cases, less than 20% of the old pool surface requires repair. If more than 50% of the old surface presents some form of defect, we will recommend the complete demolition and removal of the old surface. Full demolition of the plaster is also recommended when there are three or more existing layers of plaster in the pool. When pool renovation companies fail to thoroughly find and fix hollow spots, they are shortening the lifespan of the plaster. Sadly, the pool owner will only realize this a few years later.
• Patching of hollow spots. After removing any loose plaster from hollow spots, we fill them with a plaster patching compound and smooth these areas to ensure an even surface.
• Acid washing. We use stiff brushes and muriatic acid mixed with water to wash the entire pool surface. This helps remove stains, calcium deposits, and other contaminants. We then neutralize any remaining acid on the pool surface by applying a soda ash solution (sodium bicarbonate mixed with water).
• Pressure washing. After acid washing and neutralization, we use a pressure washer to thoroughly clean the entire surface of the pool, removing dust, debris, and any remaining contaminants. We then allow the pool to dry before proceeding to the next step.
• Bond coat application. We apply a bond coat to the surface to be covered by the new plaster. The bond coat acts as a primer that enhances the adhesion between the existing surface and the new plaster. Not all bonding products work the same way. AQUAVIX Pools uses premium-quality bonding products designed specifically for swimming pools.
• Final Inspection: Once the bond coat has dried, we do a final inspection of the pool surface to ensure it is smooth, clean, and ready for plastering.

When pool builders or pool renovation companies skip any of the steps above, they create potential issues such as delamination, cracking, or premature deterioration of the new plaster after a few years.

Pool Plaster Application

Plaster application should be done within a few days of the surface preparation work to ensure the surface is still clean and free of debris and contaminants. Applying pool plaster is a meticulous process that requires skill and attention to detail, particularly when dealing with more sophisticated plaster types containing polymer-modified cement and quartz aggregate.

Here are some key aspects of the plaster application job where AQUAVIX Pools differentiates itself from other pool builders and pool renovation companies in Fort Lauderdale, Hollywood, Miami and all of South Florida:

• Factory trained. AQUAVIX Pools is a factory-trained and certified applicator of Diamond Brite, one of the most technologically advanced quartz plaster product available in the United States. Some pool builders in South Florida prefer to apply other products that are easier to apply but don’t yield the same quality finishes.
• Single-day application. We plaster residential pools from beginning to end in a single day to avoid noticeable variations and transitions. It’s typically a full-day job. We adjust the size of our plastering crew based on the size and complexity of your pool and spa. In most cases, we’ll have 6-10 plaster workers in our plastering crew.
• Owner input. Plaster typically comes in 80-lb bags to be mixed with water at the jobsite. We have the plaster bags delivered to the jobsite on a pallet a day or two in advance, and consult with the pool owner as needed if there are any issues regarding the placement of the pallet.
• Fresh plaster mix only. Each plaster bag has a bar code and information pertaining to the place and date of manufacturing. We check the information of every bag for warranty registration purposes. We reject any bags that are more than one year old, and return any left over bags to our distributor. There are some pool builders, and many pool renovation companies, who adopt the questionable practice of accumulating bags of similar color from different jobs and different manufacturing batches to be mixed and used on future jobs.
• Patio protection. We protect the pool coping and patio, if applicable, with carton or plastic sheets to ensure plaster mix doesn’t stick where it shouldn’t.
• Quality control parameters. We prepare and apply the plaster according to manufacturer specifications, ensuring the correct ratio of water, temperature ranges, and drying times, which have changed over the years as the product composition has evolved. Others may still use parameters that were recommended decades ago, and won’t produce the same high-quality results.
• Gradual application. We apply plaster layers gradually to achieve the desired thickness of ⅜ inch, as evenly as possible to avoid imperfections. It’s a job that cannot be rushed.
• Washing methods. We wash the plastered surface using a proprietary combination of three different methods, depending on the color of the plaster being applied: light pressure washing, hand washing with a light brush, and acid washing to expose the quartz aggregate. Most pool builders only do acid washing. The difference can be clearly noticed in the quality of the finished plaster, particularly with dyed plasters.
• New fittings. We install the pool wall fittings and drain covers at the end of the job. On existing pools, we replace all wall fittings with new ones as part of the resurfacing job, whereas some pool renovation companies re-use the same old fittings.
• Jobsite clean-up. We clean up the jobsite and leave all debris in plastic bags, to be collected by our cleaning crew the next day or two.

The result of all the AQUAVIX differentiated practices in surface preparation, plaster application and pool start-up will be noticeable in weeks, months and years. Mostly in years.

Starting Up a Newly Plastered Pool

It’s important to start filling up the pool immediately after the completion of plastering. The pool should be filled up continuously, without interruption, until the water level is a few inches below pool coping, to prevent any lines from forming on the plaster.

Water from the public water supply in Fort Lauderdale, Hollywood, Dania Beach and most other municipalities in South Florida contains a potentially high level of metals and minerals that can cause stains in a freshly applied plaster. For this reason, AQUAVIX Pools uses industrial carbon filters to remove these elements from the water as the pool is being filled up. Few pool builders in South Florida take this level of precaution.

Like concrete and other cementitious materials, plaster takes about 28 to adequately cure, and requires very special care during this period. We call it the Start-Up Phase. This is the crucial last phase of the swimming pool building process. We describe it in detail in our article Pool Start-Up: The Crucial Last Step in Swimming Pool Construction and Renovation.

Here we just want to emphasize that this phase, which many pool builders and pool resurfacing companies tend to neglect or leave up to the pool owner, is extremely important for the long-term health or durability of the plaster.

During start-up, the pool water chemistry needs to be tightly controlled for the benefit of the plaster. We test the pool water at least every other day and add chemicals as needed to keep pH, alkalinity and calcium hardness within recommended ranges for the new plaster. In general, we start with a very aggressive pH (acidic), which is not healthy for either humans or pets.

Be suspicious of pool renovation companies that tell you the pool will be ready for swimming in a week or two. They’re either not taking proper care of the plaster curing process or not taking proper care of their customers.

The curing process produces some “plaster dust” that needs to brushed away from the pools walls and floor. AQUAVIX Pools will brush the entire pool surface three times a week to remove plaster dust and prevent staining. We encourage pool owners to also brush the pool during start-up if they are able to. The more frequent the brushing, the better.

As we balance the water and brush the plaster surfaces, we will keep a close eye on the plaster any signs of defects or issues, and will address any problems promptly to avoid long-term effects.

We will let you know as soon as the pool water is properly balanced and the pool is ready for swimming, around the end of the third week.

Plaster Lifespan

The lifespan of pool plaster will vary depending on the type of plaster used, the quality of the installation, and how well the pool is maintained. You should expect at least 10 years of life from quartz plaster. Properly applied and maintained, it often lasts 15-20 years or more.

Plaster Maintenance

Proper plaster maintenance consists of regular brushing and, most importantly, balanced water chemistry. For example, low pH or high alkalinity can cause the plaster to erode or etch, leading to a rough surface. Minerals, metals, and organic matter in the water can cause discoloration or stains on the plaster surface.

Plaster Warranty

There are two separate warranty policies on pool plaster: the manufacturer’s warranty against material defects and the pool builder’s or pool renovator’s warranty against application defects. It’s important to know how they work.

Manufacturer’s Warranty

While this may vary from manufacturer to manufacturer, most will offer an extended 10-year warranty on the plaster material. Unfortunately, it’s of little value in practice. Firstly, because it does not cover labor for warranty repair, even if the material is found to be defective. Labor costs constitute a much higher percentage of total plaster application costs than material costs.

Secondly, manufacturer’s warranties are voided if pool chemistry records are not available. For example, one leading manufacturer requires that pool water chemistry be “tested and documented monthly by a reputable company suing a computerized system”. Most pool owners and pool service companies do not keep such detailed records month after month for years.

Some pool renovation or resurfacing companies will highlight in their proposals the “10-year extended warranty” without highlighting the fact that it is essentially useless.

Plaster Application Warranty

The most common issues resulting from faulty surface preparation and plaster application are:

• Color variation
• Staining
• Discoloration
• Cracking
• Hollow spots
• Delamination

These same issues may also result over time from improper pool chemistry maintenance. In other words, it’s hard to attribute these plaster issues to faulty workmanship as opposed to improper maintenance. For this reason, pool builders and pool renovation companies in general do not cover under their warranty any of the issues listed above. Their standard 1-year or 2-year warranty policies cover essentially nothing. They are misleading to pool owners.

At AQUAVIX Pools, we believe that color variation, staining and discoloration can, and more often than not will, result from improper pool maintenance. We, too, exclude these items from our warranty. However, we do provide a 3-year warranty against the more serious issues hollow spots and delamination — something very few pool builders in South Florida, if any, will provide. Our 3-year warranty also covers cracking on new pools. On existing pools, superficial plaster cracking is covered as long as it is not the result of structural issues.

For more details on AQUAVIX Pools warranty policy for new pools and pool renovations, please refer to the TERMS AND CONDITIONS included with each project proposal.

Frequently Asked Questions About Pool Plaster