In various regions, rust spots are a common sight on tennis court surfaces. They are actually visible on driveways, parking lots, and other asphalt surfaces, but they are more pronounced on a colored tennis court surface.
The rust spots are the result of metallic minerals, called pyrites, that contaminate the stone used to create asphalt. Asphalt pavement and acrylic tennis surfaces allow vapor to transmit, or breathe through them. When the mineral pyrites become wet, they rust and bring the stains upward into the acrylic surfaces. These rust stains are unsightly and mostly an aesthetic issue that don’t affect the ball bounce or play of the game. However, sometimes the aggregate reacts, swells, and pops out. This leaves a rust stain and sometime a small mound with a tiny hole in the surface.
Unfortunately, there isn’t a good or compatible primer or stain blocker that can prevent this from happening. Non-breathable primers, like polyurethane, can cause much bigger problems like splits or bumps in the asphalt (due to hydrostatic pressure that pushes up from under the asphalt). The best defense is a good offense, which means:
Use only non-recycled asphalt when paving tennis and basketball courts
Do research: Stay away from limestone or aggregate sources with known contamination issues
Talk to an experienced architect and/or tennis court contractor ahead of time in order to avoid the wrong asphalt type and source.
What causes rust spots on a tennis court?
If it is too late and you already have rust spots on your tennis court, here are a few tips:
Your tennis court contractor can use a hand drill and drill out the reactive spots. Acrylic Crack Patch can be used to repair the surface holes and the court can be touched up or completely resurfaced. Sometimes there are hundreds of rust spots and drilling is not always a viable option.
This may sound silly at first, but you can pick a color scheme that closely matches and doesn’t contrast the rust color (i.e., Brown, Maroon, Red)
For more information on this, fill out the contact form on this page and we will be happy to answer your questions or put you in touch with a local tennis court contractor.
The QuickStart (10 and under) tennis format, also known as Kids Tennis, is a program that the USTA is promoting to ensure the growth of tennis. Statistics show when kids learn a sport early in their lives, they are more likely to continue playing throughout their adult life. Kids tennis takes it one step further and reshapes the tennis court surface dimensions, racquet sizes, and tennis balls to better fit the size and abilities of kids. This makes is much easier for kids to begin learning their tennis techniques, and have fun doing it!
QuickStart/Kids Tennis has changed the following standards, to meet the needs of kids:
Smaller Tennis Courts – Less area for kids to cover
Specialized tennis balls with less compression for slower and lower bounce
Smaller kid-friendly racquets for easier handling
Modified scoring rules for age groups
Many clubs, parks, and schools have begun adding kids courts to their facilities. Some have installed permanent quickstart courts, but many have been adding blended lines so that players of all ages can use all of the courts. This makes the best use of space, and provides flexibility at a minimal cost. Blended lines for kids tennis, are normally painted with a shade of line paint that is lighter or darker, but of the same family as the tennis court surface. For example, if the inside court color is blue, the quickstart lines must be a darker or lighter shade of blue. The standard court lines are always white.
There are two different sizes, when it comes to quickstart courts. The 60 foot court length is for 9 and 10 year olds, and the 36 foot courts are for ages 8 and under. If you have a court that is designated for kids, you may also check with a surfacing manufacturer or contractor about resurfacing your court with a slower playing acrylic surface. This will slow the ball bounce down and give the kids more time to get to the ball and volley.
If you are interested in finding a qualified tennis court builder near you, fill out the contact form on this page and we will provide qualified contacts. We can recommend authorized installers near you that are trained in application and knowledgeable in standard tennis and quickstart tennis court layout.
Resurfacing indoor tennis and recreational courts can have a few challenges not common to outdoor tennis court resurfacing. Indoor tennis courts do not have to contend with outdoor enemies like UV rays and harsh weather, but some indoor conditions can wreak havoc, even for the experienced tennis court surfacing contractor.
This article is relevant to all kinds of indoor acrylic courts, including by not limited to:
Acrylic tennis court surfaces are water-based and dry by evaporation. Water is the vehicle that allows the heavy coating solids to be squeegee applied. Once the coating is applied, the water begins to evaporate. If there is not adequate ventilation in the facility, the water can be trapped in the airspace above the courts and slow down the drying of the surfaces. This can cause a “marbled” look on the coating, resulting in light and dark or patchy areas.
Marbled Tennis Court Surface
Poor ventilation and cooler outside temperatures can also create problems by causing condensation to “rain” down onto the tennis court surfaces. If the inside temperatures are warmer and the ceiling is cool from colder outside temperatures, the moisture can drip onto the partially cured surface, creating blemishes. To prevent both of these issues, make sure to turn on heating or air conditioning systems to draw humidity out of the air. Open any available vents, doors, and windows to allow an escape route for moisture. Large industrial fans can also be rented and help to circulate the air, as well as push moisture out when placed at exterior doors.
If the facility doesn’t have a good way to expel and exhaust the moist, humid air, you may need to bring in industrial dehumidifiers. Until the high level of humidity is allowed to escape, the coatings will not be able to dry and cure. They will retain the marbled or uneven drying pattern, and be susceptible to damage and early wear. Plus, when the coatings are like this, it will be very difficult to get tape to stick to the surface for painting the playing lines.
As a general rule of thumb, try to keep the indoor humidity levels down, and shoot for at least 30% or lower indoor humidity.
Loose Sand On Indoor Courts | Drying & Curing
It is also common to see loose silica sand on an indoor athletic facility, and sometimes on outdoor courts. Court coatings are fortified with silica sand in order to provide a non-slip surface and ideal ball trajectory for speed of play. The latex binders in acrylic coatings need to dry completely before they can cure. Once the full cure is complete, the coatings can coalesce or fully cure. When the full cure happens, the components (sand in this case) of the coating are full bound and locked in to the coating film. In some cases, this can also have the same affect on pigments. If tennis balls become a bit colored from the surface, it is also a drying/curing issue.
The large amount of evaporating water, from the coatings, can take a while to escape from inside the building. This depends on the ventilation, and more importantly, the exhaust system of the facility. When the indoor humidity level is high, it slows down the cure of the coatings. The silica sand can be rolled out of the coatings and or can migrate out if very humid. There is no need to worry about this, as it will slow down and stop as the full cure is reached.
The quicker you can get the interior humidity level lowered, the sooner the sand roll-out will cease. Here are a few things that can help:
Rent big agricultural fans and point them outside, by an open doorway to exhaust interior humid air.
Turn up the heater and run all fans to keep air moving, with the main focus on exhausting the moist air at the same time. Important note: heaters will not exhaust or remove moist air. Turning up the heat will only help drying and curing if the moisture in the air is removed by fans or dehumidifiers. Just using the heater and fans will only blow moist air around.
Air conditioning takes moisture out of the air. Just keep a balance of using AC and heat, since heat helps the curing process more than cool conditions
Industrial dehumidifiers can also be used to bring inside humidity levels down. Check with local equipment rental stores to find ones for rent.
Also ensure that the slab/ground temperature and air temperature is well above 50 degrees F. Warmer is much better, but acrylic binders cannot cure when the temperatures are below 50 degree Fahrenheit / 10 Celsius.
It is not recommended to wash indoor acrylic sport surfaces too soon after application. You want to make sure they have had adequate time to dry and cure under low humidity for rinsing and cleaning with a floor scrubber to other similar methods. Sweeping and blowing debris off the surface is fine, but give the coatings time to cure before washing.
If the surfaces are washed prematurely, there may be some visible evidence of the color (pigments) coming out. Sometimes you will see this on the playing balls, shoes, or cleaning rags. It is not a huge reason of concern and will dissipate once the coatings reach a full cure.
Loose Sand on outdoor courts – Due to inadequate curing and low temperatures
Another common problem with surfacing indoor tennis courts is application of coatings on a very smooth surface. Indoor courts do not benefit from the wind and rains, which actually help to move debris off the surface. Dirt and sand particles, that come out of the surface, become abrasive to color coatings under the scuffing of tennis courts. Long-term, this can create a very smooth surface which makes it difficult for application of color coatings. The application squeegee can wipe the coatings off of a smooth surface, and leave a very thin coating. This can sometimes cause irregular color patches or inconsistent textures on the surface. To prevent this, apply the first coat of Acrylic Resurfacer (properly mixed with sand and water) with a squeegee, but follow directly behind with a soft, horse hair-type broom or brush. This puts a fine grooved text in the coating. Once the first coat of Resurfacer is dry, squeegee apply another coat of resurfacer, going the cross-direction. This allows the second coat of resurfacer to “grab” onto the groove finish and deposit a complete textured coat. At this point, the surface is ready to accept the tennis court color coating surface layers.
One of the most misunderstood topics and frequently asked questions are, “what is the difference between drying and curing” when it comes to tennis court paint and coatings.
Acrylic sport coatings are water-based, and latex is the binder or “glue” that adheres to the pavement or existing acrylic surface. The binder also locks in all of the components of the coating system, like pigments, sand, and other proprietary ingredients. Water is the vehicle that thins the coating solids so that application by squeegee can be achieved. Once the coating is applied, the water evaporates leaving the solids of the coating in a consistent film. This evaporation is “drying“.
At this point, the film solids are dry. They can even be walked on without a problem. However, all of the components of the coating are not entirely connected and bonded in a strong film. In order for the coating components to properly coalesce, or “melt” together, it is important that the film remain mostly dry and in temperatures above 50° Fahrenheit. This is especially important within the first 24 hours. This is “curing“.
If the coating is not allowed to achieve this initial cure, the components like sand and pigment can wash or roll out the film can fall apart to varying degrees. The level of damage or failure depends on how marginal the cure.
Tennis Court Curing Failure
Many coating and paint specifications include the statement “product shall be applied when temperatures are 50° and rising”. This means start coating in the morning when the temperatures are at least 50° and getting warmer, not late afternoon or evening when temps are dropping.
Remember, the coating must dry before it can begin to cure. Starting application late in the day puts the film at risk of dew and cooler nighttime temperatures. A good rule of thumb is to avoid acrylic paint and coating application on days when the nighttime lows are forecasted to drop below 50°. If the daytime highs are not very warm and it is cloudy, or the courts are heavily shaded, you also need to take that into consideration. The shade will increase the drying time and affect the temperature of the court surface. These factors affect drying and curing.
If you are forced to push the application on marginal days, you may want to use an infrared thermometer to check the surface temperature. Pavement absorbs and holds cold for longer than most people think. In Spring and Fall, the sun is further away and not as intense. The pavement surface isn’t able to warm up as quickly as it does in the summer.
If you are a contractor and your customer is pushing you to apply when the temperature and weather is not within acceptable range, make sure to provide them with a copy of the coating manufacturer’s specifications and ask to reschedule application when conditions allow.
What is the best tennis court surface? That depends on what you are looking for in a surface, of course. The vast majority of players and facility managers prefer acrylic tennis court surfaces, and here are just a few of the main benefits:
Very low maintenance
Durable and compatible with all climates
Textured & Customizable for desired speed of play
Aesthetically pleasing
Cost effective & Affordable
Acrylic tennis court surfaces actually benefit from the wind and rain. Properly built tennis courts should have a 1% slope for drainage, so rain helps to keep the surface clean and somewhat free of dirt and debris. Whether you live in a very hot and dry area or a cold and moist location, acrylics can withstand all of the above. The standard resurfacing cycle, with a high-quality acrylic tennis court surface, is every 5 to 8 years.
Acrylic Tennis Court Surface
Another advantage of acrylic tennis court surfaces are their ability to be customized to all desired paces, or speeds of play. The ITF (International Tennis Federation) has a pace classification program where tennis surface manufacturers send in factory-textured samples and have them tested for speed of play. The ITF and approved independent testing labs perform specific procedures and classify each sample as a specific pace. The current pace categories are: slow, medium-slow, medium, medium-fast, and fast. There are only a few brands that currently hold all five paces and they are acrylic (not clay, tiles, or grass surfaces). The texture that determines pace also makes for a safe, non-slip playing surface.
