Finding blisters or bubbles on tennis court surfaces is a fairly common problem, especially on concrete substrates. Many court owners are baffled by the fact that sometimes blisters are present and other times they are not. The first thing they do is blame the resurfacing contractor, because it was good before, and now the problem occurs after the new surface has been applied.
Acrylic tennis court surfaces are semi-permeable or breathable and allow small amounts of moisture vapor to pass through from under the board. However, if there are large amounts of moisture trying to penetrate, it can lead to this situation. When a tennis or basketball court is not built with a proper perimeter drainage system to divert rainwater away, a lot of moisture can end up right under the court. When the sun heats the surface, water is drawn upwards in the form of steam. This creates hydrostatic pressure, and can break the bond between the coating and the asphalt or concrete surface. The result is multiple bubbles and blisters on the surface of the court. Concrete surfaces should also have a 10mil vapor barrier installed when building the court, to prevent this from happening. Unlike asphalt, concrete is very dense and tends to create higher levels of hydrostatic pressure. This is why the problem often occurs in concrete courts.
In addition to poor drainage, surface blisters and bubbles can also become a problem when too many layers of surfactant are applied. This can happen after many years of resurfacing courses. When a tennis court is being retrofitted, between 3 and 10 layers of surfacing material are applied, depending on whether it is a hard court or a padded tennis court surface. The standard peeling cycle should occur every 4 to 7 years. At some point, around the fourth or fifth flatness, the owner may want to consider having the tennis court contractor remove the existing coating, and return to the pavement. This helps reduce the possibility of bubbles or blisters, and ventilation issues. Also, tennis court coatings contain silica sand or are functionally mixed to fill voids and texture the playing surface. This creates a non-slip security, and sets the pace of the game. The sand also breaks the surface tension of each coat of paint and allows it to breathe better. Thus, it is recommended to limit the sand in each layer of material.
In some rare cases, occasional bubbles may appear on a sports surface with adequate drainage. This is most likely to occur during extreme weather patterns that bring continuous rain and overburden drainage systems. If the surface has not been exposed to this problem in the long term, the bubbles will usually decrease and disappear without further problems. Random bubbling can also be injected with an acrylic rubber to re-adhere the paint to the surface of the pavement, if necessary. A professional water skier can take care of this at a minimal cost.
When constructing a sports field, make sure that the tennis court construction company is familiar with the American Association of Athletic Builders’ guidelines for proper sports construction. The best way to ensure this is by contacting the manufacturer of tennis court renovation products and asking for qualified tennis court contractors in your area.