Substitution Request Form
Fill out this form and click Download PDF. You can then email or print it for the Architect/Engineer review.
Not an official AIA/ASLA form; use is subject to the project’s Contract Documents and substitution procedures.
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Puddles and Standing Water on Athletic Courts & Coating Damage
A common enemy to the longevity and playability of 100% acrylic athletic court coatings is the seemingly innocuous standing water and puddles. Beyond the immediate inconvenience to players and game delays, the presence of water on your tennis or basketball court can lead to significant and costly damage to the playing surface.
Acrylic athletic court coatings, while durable, are not designed for prolonged submersion. When water sits on the surface, it begins to break down the acrylic binder, diminishing its adhesion and integrity. Even more insidiously, standing water can seep into the porous coating. As the sun’s heat returns and evaporation occurs, this trapped moisture is pulled back out, creating unsightly and damaging bubbles and blisters on the court surface. These imperfections not only detract from the court’s appearance but also create uneven playing conditions and can lead to further deterioration.
The American Sports Builders Association (ASBA) provides crucial guidelines for proper court construction to mitigate these issues. Whether your court is built on an asphalt or concrete base, the ASBA emphasizes the importance of a well-engineered slope for efficient drainage. For asphalt courts, a typical slope of 1 inch in 10 feet (1:120) is recommended to ensure water flows off quickly. Concrete courts also require the same pitch to prevent ponding. Proper grading and compaction of the sub-base, along with a consistent and accurate surface slope, are paramount in diverting water away from the playing area.
While solutions like Acrylic Patch Binder patching mix can be used to level smaller, problematic puddles, they can imperfect and temporary fixes. The most effective and long-term solution to prevent ponding and coating damage is proper court construction and drainage from the outset. Investing in ASBA-compliant construction ensures your court remains free of standing water, protecting your investment and providing optimal playing conditions for years to come.
It is also important to maintain the area around the court edge and make sure to prevent grass and vegetation buildup. This can create a dam on the edge of the court, especially the low edge of drainage. Water or melting snow can create ponding that is held by the court edge obstruction causing coating damage.
Importance of Power Troweling Concrete for Sport Surfaces
Power troweling is a vital step in preparing post-tension & reinforced concrete tennis courts for a medium broom finish and the application of 100% acrylic coating systems. This process significantly influences the long-term performance, durability, and appearance of the finished court. It also plays a critical role in minimizing issues such as water intrusion, blistering, and peeling of coatings. Here’s why power troweling is essential:
- Creates a Dense, Uniform Surface
- Power troweling compacts and smooths the fresh concrete surface, resulting in a dense and consistent slab.
- This uniformity is especially important for post-tension concrete, which is subject to internal stresses and movement. A properly troweled surface helps minimize future irregularities and maintains the structural integrity of the slab.
- It also ensures the surface is level and free of significant high or low spots, which helps support proper water drainage and uniform coating coverage.
- Minimizes Surface Capillaries
- One of the key benefits of power troweling is the reduction of surface capillaries—the tiny channels within uncured concrete that can absorb and transport moisture.
- By densifying the surface and closing these capillaries, power troweling significantly reduces the potential for moisture intrusion from below or within the slab.
- This is crucial for preventing issues like blistering, bubbling, or peeling of acrylic coatings, which are often caused by trapped moisture vapor escaping through the coating system after application.
- Establishes a Stable Base for Broom Finish
- Once the concrete is troweled, a medium broom finish can be applied to create a uniform surface texture that is ideal for coating.
- Troweling ensures the broom finish is laid over a stable, well-consolidated substrate, which enhances its uniformity and reduces surface variability.
- This consistency supports an even coating application and contributes to the overall aesthetic and performance quality of the court.
- Improves Coating Adhesion and Performance
- 100% acrylic coatings require a clean, sound, and stable surface to bond effectively.
- A troweled surface provides fewer voids and eliminates surface laitance or dusting that could otherwise interfere with coating adhesion.
- This enhances the mechanical bond between the concrete and the coating system, reducing the likelihood of premature failure and helping the surface withstand environmental stressors over time.
- Increases Resistance to Surface Defects
- Power troweling helps prevent common surface issues such as:
- Dusting
- Micro-cracking
- Surface flaking or scaling
- These defects, if left untreated, can compromise the performance and appearance of both the concrete and the coating system.
- By producing a smooth, consolidated surface, troweling extends the functional life of the court.
- Aligns with Industry Standards
- The use of power troweling followed by a broom finish is consistent with the American Sports Builders Association (ASBA) guidelines and coating manufacturers’ recommendations.
- Following these best practices helps ensure the finished court meets performance, durability, and warranty standards.
Conclusion
Power troweling is not simply a finishing step—it’s a crucial part of preparing post-tension concrete tennis courts for a high-performance acrylic coating system. It enhances surface uniformity, minimizes capillary pores to reduce water intrusion, and ensures a stable base for both the broom finish and coatings. These benefits collectively prevent coating failure and extend the life and quality of the court. Proper troweling sets the foundation for a durable, professional-grade playing surface.
What type of silica sand should be used in acrylic sport surfaces?
When sourcing sand for use in 100% acrylic sport coatings, it’s important to use quality sand. There is a large variety of sand characteristics when sourcing throughout the United States & around the world. Here are some important factors when researching sand for acrylic sport surfaces:
- For acrylic color coatings, shoot for a sieve size of 70-90 mesh. The higher the number, the finer the sand particle.
- The ideal shape for color coating sand is round. Angular sand can be used for a grittier texture, but it can also increase wear on the pickleball or slower play with tennis balls. Angular sand can increase wear on pickleballs and create more ball fuzz with tennis balls. Angular sand can also result in more visible application, or squeegee marks.
- Since the standard method of coating application is a soft rubber squeegee, the size of the sand sets the coating thickness. The larger the sand, the thicker the coating. This also affects the coverage rate. More coating is used with larger sand and less with finer sand.
- Look for sands with low-to-no dust. Dust in sand can lead to less vibrance and more chalky appearance of the color coatings. It can also diminish the UV resistance of the color and lead to earlier fading of the finish. When looking as a sand sieve analysis, look for low percentages in the “Pan”. The pan holds fines that fall through all of the sieve “screens” and lands in the pan at the bottom.
Are finer and coarser sands acceptable for use in color coatings?
When looking at a sand sieve analysis, there is never 100% of a certain size in any lot of sand. There is a range of particle sizes in various percentages within all sands. Most technical data sheets for sand will include the sieve analysis, and some of them will provide the average (or AFS). So if a specification calls for 100 mesh sand, it would be acceptable to use something close like a 80 to 90 mesh sand since it likely has particles within the mix that are over and under this range.
What is the best type of sand to use in Acrylic Resurfacer?
Acrylic Resurfacer is an industry-standard product that is used as the base coat(s) under colored acrylic playing surfaces. Acrylic Resurfacer is used for the following:
- Filler coat. Fills voids in asphalt or concrete pavement surfaces.
- Helps to hide crack repairs, low spot leveling and other surface repairs
- Provides texture on an existing smooth acrylic surface to prepare for consistent application of new textured color coatings. This helps to ensure the proper mil thickness of the color coatings, which leads to longer wear and superior hiding.
- Excellent primer coat for adhesion of the surfacing system.
The size and shape of the silica sand used in acrylic resurfacer is directly attributed to the performance. Thus, it is recommended to use a larger & angular shaped silica sand somewhere between 40 to 60 mesh (clean and dust-free). This helps to create a thicker hiding coat which is also perfect for filling voids in pavement. If a finer sand is used in Acrylic Resurfacer, the filling and hiding capacity is greatly diminished.
Recommended sand for Acrylic Patch Binder
Acrylic Patch Binder is another common repair product that is used on acrylic courts. Patch Binder is a 100% binder that is mixed on-site with portland or hydraulic cement, and silica sand. It is used to fill and level birdbaths, or low areas where water puddles on a court surface. Patch Binder mix is also used to fill cracks on asphalt and concrete athletic courts. Since we want to fill low spots and cracks, it is ideal to also use a 40 to 60 mesh angular silica sand. This should be the same type of sand that is used in Acrylic Resurfacer.
Summary of Sand for acrylic sport surfacing systems
The correct sand shape and size is very important, when sourcing for acrylic sport surfacing systems. Contact your local SportMaster representative for more information & the best sources of silica sands. If you’re having trouble finding a good local source, you may want to consider buying factory-mixed coatings. SportMaster produces Acrylic Resurfacer and Color Coatings in both non-textured and factory-textured options.
Do Concrete Pickleball Courts Need Saw Cuts or Expansion Joints?
With the high volume of concrete pickleball courts being built, the common question “Do concrete pickleball courts need saw cuts or expansion joints” comes up frequently.
The short answer is “maybe”.
Saw Cuts & Expansion Joints | Pickleball Courts
The American Sports Builders Association provides up-to-date construction guidelines for sport surfaces in the US and abroad. In conjunction with USA Pickleball, the governing body of pickleball, ASBA created a book with pickleball court standards. This book is utilized by architects, engineers and other pickleball courts specification writers.
Currently, the recommended substrates for pickleball courts are asphalt & post-tensioned concrete. Post-tensioned concrete slabs are supported by a grid of steel tendons in a protective sheath that are tensioned after the concrete is placed. These slabs are considered crack-resistant due to the support of the tensioned cables and do not need saw cuts or expansion joints.
Why are saw cuts & expansion joints placed in concrete?
Concrete is a very hard substrate, and it’s very important that the sub-base is properly laid, sloped for drainage & compacted. Another popular concrete construction method is reinforced concrete. Reinforced concrete slabs contain rebar, or steel reinforced bars that lend extra strength within the concrete slab. For most applications, like driveways, saw cuts are placed after the concrete is formed to control cracking. However, once the saw cuts are placed, you always have a cut through the slab that will open and close during expansion and contraction from temperature swings. The saw cuts are straight and consistent, to minimize random cracking in varying directions.
Pickleball & Athletic Courts on Reinforced Concrete
Previous specifications through the ASBA mentioned use of reinforced concrete for tennis courts. Tennis Courts are 60′ x 120′ and the recommendations were to place saw cuts under the net line and between adjacent courts. This prevented cuts in the playing areas and potential vertical displacement, or trip hazards, for the players. Based on the tennis court saw cut recommendations, you basically had two 60′ x 60′ slabs with no saw cuts on each side of the net. Pickleball courts are usually 30′ x 60′, so many people choose to only put a saw cut under the net line to avoid visible cracks and potential heaving of the slabs between joints.
Acrylic Crack Filler | Uses and Longevity
Acrylic crack fillers are usually applied before application of court coatings to fill the saw cuts. This helps to keep the coatings from puddling in the joints and maintain a cleaner look. However, movement in the joints will cause a hairline crack to appear, which will gradually widen. Some joints will reopen quickly and others may take longer to appear, depending on the amount of movement and moisture under the court. Crack fillers can be reapplied as needed, to minimize moisture intrusion, but this is a continuing maintenance cycle. The saw cuts/expansion joints are doing their intended job by allowing movement to minimize stress on the rest of the slab.
Flexible and Elastomeric crack fillers
There are also flexible elastomeric fillers that can be used in saw cuts and expansion joints. These products have better elongation in the cracks, but they can also lead to other issues. In some cases, the flexible fillers can be pushed upwards when the slabs come back together, leaving a small hump that sticks up above the joints. This is not ideal for safe footing and consistent ball bounce. They can also slump when the slabs move apart, leaving a small valley in the saw cuts. For these reasons, many opt for the harder sand and cement filled acrylic crack sealants. These situations are solely dependent on the construction of the court and weather variables. Indoor courts are usually more consistent due to indoor temperature control and the saw cuts usually exhibit less movement than outdoor slabs.
Can I Avoid Seeing Saw Cuts on my Pickleball Court?
Here are some of the best ways to avoid seeing saw cuts on your pickleball court:
- Management by construction methods
- Post-tensioned concrete or asphalt construction
- Minimizing saw cuts by strategic placement (under the net line and out of playing area)
- Crack fillers (temporary methods and reapplication)
- Note* reapplying crack fillers will likely leave unsightly shade differences over the cracks.
Remember, saw cuts are uniform and are designed to prevent breakage and cracking throughout the slab. If the cracks open, they are preventing additional damage to the slab and other random cracks. Asphalt courts are a bit more flexible, but the asphalt binders will also become brittle with age and will become more susceptible to cracking and settling. Compaction, drainage and overall construction is also important to longevity of asphalt courts.
Should I Close My Recreational Courts For The Winter?
One of the most frequently asked questions, especially in northern climates, is: Should I close my recreational courts for the winter? Once cured, acrylic court surfaces are very durable and require little maintenance. However, below are some items to consider.
Does ice and snow damage acrylic court surfaces?
Athletic courts, like tennis, pickleball, and basketball courts, should be built with a 1% slope to allow positive drainage without creating difficult playing conditions. This helps the court surface to dry quicker, but also to prevent water damage to the acrylic surfaces. Acrylic court surfaces do not like to be submerged in water for long periods of time. However, as long as the coatings have time to dry, water doesn’t affect the longevity. Since ice and snow is in a sold state, it would not soak into the surface and cause damage as quickly as puddled water may do.
Snow Management & Debris | Winter Court Maintenance
The biggest issue with keeping your court open in the winter is snow management. There is no problem with playing on courts when it is cold outside. However, if you have piles of snow on the surface, here are a few things to keep in mind:
- Try to limit physical removal of snow and ice. (Metal shovels and tools with a sharp edge can damage the surface. Try to stick with plastic shovels or wait for snow to melt before playing.
- Using salt or other granule-type snow melt products can lead to extra abrasion to the surface. When playing on the courts, any debris under foot can damage or shorten the life of the coatings.
- Make sure to also remove any debris that has fallen, like leaves or pine needles. Not only does this minimize abrasion but it also prevents other organic staining or damage from wet rotting leaves.
Court Accessories During The Winter
If you decide not to use your court during the winter, you may want to take down and store any windscreen that you are using. This will help to prolong the life of windscreen. If you decide to keep the tennis or pickleball nets up for winter play on nice days, you may want to reduce the tension on the net a bit. Not enough to let it flap around in the wind, but a little tension relief can reduce extra strain on the net post footers and pavement during cold temperatures. If you do decide to close your court for winter, remove the net and slide the tennis/pickleball posts out of the ground and cover the surface holes with a cap/plug.
Maintaining Positive Court Drainage
As previously mentioned, it’s very important for court surfaces to drain and not hold water. During the winter, and really throughout the year, keep an eye on the court and make sure that nothing is stopping the flow of your court drainage design.
- Make sure any drains around the court are not plugged with debris, like fallen leaves from the fall. This will prevent back-up of water onto the court surface.
- Keep vegetation trimmed around the edges of the court, especially on the low end of drainage. Failing to do so can also create a dam for positive drainage.
- The court should be built up a bit so that water can flow off the court to the drainage plan. Make sure dirt or other obstructions are lower than the court surface edge, as well.
Winterizing Your Tennis or Pickleball Court
Regardless of your decision to keep your court open for play during the winter, here are some court winterizing tips (recap):
- Before the weather gets too cold, make sure to examine your court surface for cracks. Fill the cracks with an acrylic crack filler to minimize the flow of water into the base of the court. The less water that you have freezing and expanding under the base, the longer your court will stay in good condition. Make sure to make these repairs far before the nighttime lows dip past 50 degrees F / 10 degrees C.
- Walk the perimeter of the court and make sure there is nothing blocking drainage on any side of the slab. Ensure that any visible drains are not blocked or plugged with debris.
- Keep the surface free of debris, such as leaves, pine needles, and all other tree matter.
- If you choose to close the court for winter, remove the net. Optionally, if your posts are removeable, you can slide them out and store them. If you do remove them, plug the surface holes with a cap (all post manufacturers make caps for the sleeves). If you leave the posts and nets up, take a little tension off the net during the winter.
- Avoid using sharp or potentially damaging tools on the surface for snow removal. Salt and snow melting pellets may shorten the life of the surface, so use sparingly and make sure to blow or broom off excess particles to minimize damage.
How long should asphalt cure before applying sport surfaces
Question: How long should asphalt cure before applying sport surfaces?
Answer: New asphalt should cure a minimum of 14 to 30 days, prior to application of a sport surfacing system.
Asphalt Curing & Sport Surfacing Systems
Asphalt consists of rock, generally limestone, and liquid asphalt. The liquid asphalt, also referred to as asphalt cement or asphalt binder, is the “glue” that holds the rock together and enables the paving layers to bind to the prepared base.
When asphalt is newly paved in place, it exudes some excess asphaltic oils during the initial curing of the slab. It’s important to let some of the oils cure out, before application of any coatings, sealants, and sport surfaces.
Risks of Inadequate Asphalt Curing Before Surfacing
If the asphalt is too rich with asphalt binder and hasn’t had the opportunity to cure, or release the initial gush of asphalt oils, it can potentially lead to:
- Lack of proper coating system adhesion (which may result in peeling and other paint and coating failures)
- Staining, yellowing, and discoloration of the sport surfaces and coatings.
What are prime conditions for asphalt curing?
Hot & sunny conditions will help to pull the rich asphalt binder up to the surface. Once the excess oils are pulled to the surface, it is also important to have rainfall. This helps to rinse some of the oils away and “unplug” the pavement voids. The combination of sun to draw the oils to the surface and water to rinse them away, allows for continuous prime curing conditions.
If the conditions are good, the asphalt can be ready to coat in a minimum of 14 days. The safer option is to wait 30 days, if time allows. If conditions are warm and sunny after paving, but the area experiences a drought, rinsing of the surface by manual methods can help to keep the curing process in motion. Indoor asphalt curing can take longer than 30 days, to ensure sufficient release of oils.
Since there are variables, and no actual testing processes to guarantee initial curing, it is best to allow proper time for adequate curing. Sport coating manufacturers & experienced sport surfacing contractors are the best source for recommendations, when it comes to proper application timing. Rushing to resurface your tennis, pickleball, or basketball court before the asphalt is ready can lead to expensive problems now or down the road.
How To Properly Prepare Concrete For Sport Surfacing Athletic Courts
Athletic & recreational courts (tennis, pickleball, basketball, etc.) are built from either asphalt or concrete pavement. The type of substrate used is normally determined by region, cost, preference, availability or site access.
Each substrate (asphalt or concrete) has its own set of requirements, when it comes to application of acrylic sport surfaces. This bulletin will discuss how to properly prepare concrete for sport surfacing athletic courts.
Concrete Court Construction
When it comes to proper concrete court construction, there is a long “to-do” list. As with anything, there is always a good, better, best list of what to do and why it is important. If you are considering having a recreational court built, we recommend getting a copy of the American Sports Builders Association’s construction & maintenance manual. They publish and sell these for tennis or pickleball, which is also useful for basketball and other sports. That being said, we will reference a short list of the most important factors, prior to application of acrylic surfaces.
Install Vapor Barrier
Prior to pouring the concrete slab, a vapor barrier should be installed to prevent upward migration of ground moisture. This normally consists of two sheets of 6 mil polyethylene plastic sheeting, laid in opposite directions. Make sure it is overlapped and taped at the joints. The vapor barrier is on top of the stone base and under the concrete slab.
Ensure Adequate Perimeter Drainage & Slope
Another very important factor, when trying to minimize water accumulation under the concrete slab, is good perimeter drainage. If one or both of these items are lacking (vapor barrier & perimeter drainage), your court surface could be in danger of bubbles or blisters in the coating. In most cases, this will lead to peeling of coatings and bare spots down to the concrete. Court surfaces should be sloped at 1% in one direction, which is 1″ fall in every 10 feet. This helps to keep water flowing off the court and ensures fast drying surfaces and less standing water.
Medium-broom Finish or Similar Surface Texture
When pouring and finishing the concrete, make sure that the concrete contractor applies a medium-broom finish on the surface of the concrete. This is very important to a good physical bond of the sport coatings. A steel-troweled finish is too smooth and will also raise the chances of peeling surfaces. If the concrete is already in place and doesn’t have a medium-broom finish, you can use specialized equipment to achieve sufficient texture. The most commonly used piece of equipment is a shot blaster. For more information, check out our dedicated page on shot blasting concrete court surfaces.
Allow Full Cure Before Coating Application
The curing process of concrete is a chemical reaction that takes 28 days to complete. During the process, quite a bit of water is escaping from the slab and depositing high-alkaline salts on the surface. It is important to allow a full 28 day minimum cure, prior to moving forward with coating application. Also, after the full cure and prior to application of coatings, the concrete slab must be acid etched (or acid washed). This helps to create a neutral PH on the surface for an ideal chemical bond of coatings. This is fully explained on our page, acid etching concrete sport surfaces.
One more note on curing, avoid using curing compounds on concrete court surfaces. Once the concrete is poured, it will instantly begin to losing water via evaporation. If the temperatures are hot, water will leave the wet slab quickly, and this could lead to surface cracking (like mud cracking in a puddle). To prevent this, most concrete contractors spray curing compounds on the surface to slow down the evaporation of water. Many curing compounds are made up of oil based or incompatible materials that can leave a residue on the the concrete surface. This residue, or film, can potentially cause a bond breaker and lead to failure of the acrylic sport coatings. To avoid this situation, make sure the concrete contractor moisture cures the slab. This is performed by keeping the slab wet after pouring, with a covering of moistened burlap, a polyethylene sheet, or other curing paper. After 7 to 10 days, it can be allowed to dry and cure under normal conditions without the keeping the slab moist.
Not sure if curing compounds have been used, or you know they have been used? The surface can be shot blasted to remove any bond-breaking films. Note, you can pour a small amount of water onto the concrete slab to see if water beads up on the surface. If it does, there is likely a curing compound or sealant on the surface.
Application Of Concrete Primer & Sport Surfaces
At this point, the concrete slab should be ready to receive the sport surfacing system. Once the surface is clean and dry, apply one coat of SportMaster Acrylic Adhesion Promoter. This product acts as a concrete primer and helps the SportMaster color coating system adhere to the concrete. It also helps to lock down potential concrete powder, or efflorescence, that may migrate into the color coating “paint” layers and leave a hazy color hue.
After the Acrylic Adhesion Promoter dries, Acrylic Resurfacer and the colored surface coatings can be applied. There is no special timing required with Acrylic Adhesion Promoter. The successive coatings can be applied as soon as it is dry to the touch, or on another day thereafter.
One or two coats of Acrylic Resurfacer is usually sufficient to fill broom patterns and concrete surface texture on a new concrete court surface. Follow that with SportMaster color coatings, 2 coats minimum, and striping to complete the new concrete recreational court surfacing.
Shot Blasting Concrete Sport Surfaces | Tennis – Pickleball – Basketball
A shot blaster is a machine that is commonly used to create a texture, or profile, on concrete. There are various sizes of “shot” that can be used in these machines. Shot blasters propel the shot particles, or media, onto the surface and suck it back in to create texture. Our coating systems, and many other coatings, need some texture on the surface to create a good physical bond. We recommend concrete being finished with a medium-broom finish, as opposed to a smooth trowel finish. Sometimes this doesn’t happen, so the best way to get a good texture profile is to shot blast the smooth surface.
This is also a good way to “open up” the concrete and remove potential curing compounds or surface residue that can cause bonding issues.
Shot Blast Profile For Tennis, Pickleball, and Basketball Court Surfaces
The shot blast industry has a shot blast profile chart that lists various levels of texture, created by the shot blast. It also ties each of the texture levels to a recommended thickness of coating system. In other words, the thicker the coating system build, the more texture needed on the surface. Our sport coating systems, based on the average thickness and factoring in multiple resurfacings over time, work well over a shot blast profile of CSP3 or CSP4. Don’t worry, if the shot blaster profile turns out with a little too much, Acrylic Resurfacer will fill in and hide the voids. This may require extra coats, but better to have more than less for good physical adhesion.
Where To Find Shot Blasters For Court Surfaces
Shot blasters come in various sizes and are commonly rented at equipment rental stores. Many times, flooring contractors that apply epoxy and polyurethane (industrial coatings) own these machines. It may be best to hire and/or subcontract this work to contractors with experience to get past the learning curve. They usually have larger ride-on models that get it done quickly, too.
What size shot media should you use?
When trying to achieve a CSP 3 or 4, there are multiple variables in play. You should try to obtain a medium-sized steel shot. This would generally be S390 or S460 steel shot.
However, shot size is not the only factor in producing the CSP 3 or 4 finish. Here are a few other considerations:
- Travel speed of the blaster: Slower speeds will create a more aggressive profile.
- Amount of shot released: A higher load will result in a more textured profile.
- Hardness and Condition of the Concrete: Denser, harder concrete will require more aggressive blasting to achieve the same profile.
Applying Sport Coatings on Concrete Surfaces | Specifications
To see the SportMaster engineering specification, which includes the basic steps of the process, click on the link below. This will open a .pdf version of the document.
Applying Sport Surfaces On Concrete
Visit our full page for more information on proper preparation of concrete sport surfaces.
Acid Etching Concrete Sport Surfaces
Sport and game courts are as popular as ever, especially with the extreme growth of sports like pickleball and continued popularity of basketball, tennis and multi-sport games and courts.
SportMaster has a multitude of durable and vibrant acrylic surfacing systems that are designed for asphalt or concrete courts. Each substrate has a somewhat different approach to preparation, prior to application of the sport surfaces. We are going to discuss a common step that is required when coating concrete courts for the first time. This process is called acid etching or acid washing.
What Is Acid Etching? | Concrete Court Surfacing
Acid etching is the process of pouring a mixture of water and acid on a fully cured concrete slab. Generally, either muriatic or phosphoric acid is used, but muriatic is a bit easier to find. In a nutshell, acid etching promotes an ideal environment for chemical bond of coatings to concrete. If done properly, acid etching only has to be performed once. If a concrete slab has not been acid etched or coated, even years after it was built, it’s always a good idea to do it.
Why do I Need To Acid Etch My Concrete Court Surface?
Concrete goes through a chemical curing process after it is poured. It takes 28 days for a concrete slab to completely cure. There is a good bit of water in the concrete mix and as the concrete is curing, water is continuously wicking and evaporating upward and out of the slab. As the water is migrating upward, it brings efflorescence, or salts, that reside in the concrete. After the initial curing phase is complete, there is a crust of efflorescence on the surface of the concrete.
Lesson In PH & Surface Chemistry
PH, or “potential of hydrogen” is the scale of acid vs base. The PH scale goes from 0 to 14, whereas 0 is very acidic and 14 is very basic (alkaline). For ideal chemical adhesion, coatings prefer a neutral environment. This would be 7 on the PH scale. When concrete cures, the surface crust or salt deposits, are very high in alkaline (a PH around 13.5). The process of acid etching neutralizes the high alkaline crust and brings the surface PH back to neutral. The acid washing process also helps to break down and rinse away the powdery efflorescence. This also prevents flaking or peeling of coatings & migration of powder into the color coatings resulting in a cloudy appearance.
How To Acid Etch A Court | Pickleball – Basketball – Tennis
In this section, we will outline how to acid etch a concrete court surface. But first, here are a few pointers:
- Make sure to acquire and wear adequate safety gear, when working with acid. Thick rubber gloves, safety glasses, and relevant clothing and boots. Avoid breathing in the direct fumes of concentrated acid and ensure that you have plenty of air flow when inside.
- As a general guideline, it should take around 2 to 3 gallons of acid to etch a smaller court, like a 30′ x 60′ pickleball court & around 8 to 9 gallons for a full tennis court (60′ x 120′).
- Protect any sensitive plants or surrounding materials around the border of the court. Even though you will be rinsing off acid that is very diluted and has already reacted with the surface, it’s a good idea to minimize contact as much as possible.
Step 1: Spray water on the court to dampen the surface. This helps the mixed acid and water to flow and better penetrate the surface.
Step 2: Properly mix the acid and water, following the dilution measurements on the acid bottle. There should be directions for “masonry etching” on the bottle instructions. Remember to fill the empty bucket with water first and then pour the correct amount of acid into the water. This helps to prevent splashing of acid.
Step 3: Pour the acid & water mixture onto the concrete, working in small areas or sections at a time. If you’re able to have a helper, have the 2nd person immediately broom the solution around with a push broom to make sure the acid comes into contact with every square foot of concrete. Make sure that you don’t pour the acid mixture and expect it to span a long distance. Instead, pour around a small zone in a tight “s” pattern to ensure direct contact with the surface. Since the acid mixture reacts instantly with concrete, the potency diminishes as it spreads.
You will notice a cloudy appearance in the liquid and minor bubbling reaction, which means the acid is working to neutralize the surface salts.
Step 4: As you move on from section to section, you will notice the reaction dissipates in the previously treated area. At that point, you can rinse those areas off to flush surface contaminants and move the neutralized acid solution off the court surface. If possible, it’s best to start on the high end of the court and slowly move all of the water toward the low end of drainage. If possible, try to keep the entire court damp throughout the process, which keeps the sediment from sticking to the surface.
Step 5: After you have etched the entire court surface, and rinsed away most of the remaining acid mixture and sediment, it’s always good to do a final rinse of the entire surface. This ensures a completely clean surface, free to any potential acid or other contaminants. If you’re indoor and don’t have available drains, a floor cleaner machine can be used for a good final cleaning.
*Remember to protect and avoid adjacent concrete areas that are not receiving the sport coatings, as the acid can create a different color or appearance to exposed concrete. This is hidden when coatings are applied over the acid etched play areas.
Common Misconception About Acid Etching
Many people think that acid etching creates a physically textured surface for the coating to adhere. This is not the case, as the actual purpose was established earlier in this bulletin. It is still very important for the concrete surface to have a medium-broom finish or similar. That is very important for physical adhesion of coating systems. Remember, the two most importance factors for good adhesion of sport coatings is:
- A good surface texture/profile for physical adhesion
- Neutral surface PH for excellent chemical adhesion