Get Wise to Cracks
There’s no getting around it: Asphalt courts will crack. Here’s what you can do to repair the damage.
By Dan Clapp, Armor Crack Repair System, and Chris Rossi, Premier Concepts Inc.
Cracks have been the bane of the hard-court industry for many years. But it seems as though courts now are cracking faster and to a greater extent than ever before.
While asphalt courts are significantly more affordable than concrete, asphalt’s major drawback is its tendency to crack. There are a number of reasons why cracks develop. For instance, improper site preparation, defective materials, or faulty installation can each lead to cracking.
But after many decades of asphalt court construction, it appears clear that besides the weakening of asphalt and asphalt binders, a big reason why asphalt courts crack prematurely is due to a combination of not enough structural material for the conditions or the region and improper preparation and a lack of proper time between construction steps.
Flaws in the Process
Essentially, either the court may not be constructed with enough base stone, base asphalt and/or surface asphalt, or some part of the process may be rushed. For instance, the contractor, for one reason or another, may not allow the proper amount of time to compact properly, or to compact in lifts, or to allow for some settlement to occur before laying the asphalt, etc.
Often, project owners may be to blame for requesting the absolute minimum amount of materials or procedures in order to cut costs. Because contractors simply aren’t in a position to press the issue with owners, they can’t ensure that the proper amount of materials will be used. Project owners have also compromised the success of asphalt courts by rushing the process.
The customers, therefore, can create flaws in the court right from the outset. Fighting costs and forcing contractors to cut time both conspire against asphalt tennis courts, laying the groundwork for cracks to develop.
Flaws in Asphalt
Also working to crack the surface are flaws inherent to asphalt, such as the quality of asphalt and the fact that the court is paved as a jointed system. In addition, asphalt has a natural tendency to shrink as it weathers and ages. And over time, asphalt will lose its flexibility and become more brittle.
The pressure created by the tension of the net on the net post footers is a factor in cracking. The placement of concrete in and around the court for fence posts, net posts and center-strap tie-downs also creates problems due to the different expansion and contraction properties between concrete and asphalt. Other factors, such as continual ground movement, settlement of the subsurface, weathering, and improper construction, can all work to crack hard courts, especially asphalt.
Surface Cracks and Pavement Cracks
Surface cracks, which are just on the top of the asphalt, can be distinguished as follows:
- Hairline cracks: Small, irregular cracks present over large areas of the court. If left untreated, they will develop into more serious cracks.
- Alligator cracks: These interlocking cracks make a pattern over the surface, resembling an alligator hide.
- Shrinkage cracks, or stress cracks: These are a random pattern of interconnected cracks with irregular angles and sharp corners. They are usually very small.
Products that contractors can use to repair surface cracks include very flexible surface coatings, fabric membranes, or a new asphalt overlay.
Pavement cracks go all the way through the four inches of asphalt. The types of pavement cracks include:
- Heat-checking cracks: Caused during compaction of the asphalt when the roller “stretches” the asphalt horizontally.
- Structural cracks: These penetrate the total thickness of the asphalt. New cracks are very thin and grow in width as they age.
- Reflection cracks: Appearing in asphalt overlays, reflection cracks simply mirror the crack pattern in the old pavement surface beneath the overlay.
- Radial cracks: These radiate off the corner of the concrete net-post footings.
Crack Repair Products and Alternatives
The last five years or so have seen the development of products that will help to maintain cracks more effectively, and at reasonable prices. Several of these types of products involve using polyurethane or acrylic-based caulks as new types of fillers, thus extending the life of a simple crack-fill project.
Several products utilize fabrics that have the ability to stretch extensively, yet return to their original state and position to isolate the crack from the repair system, thereby preventing the crack from reflecting through the repair system.
Also, full surface system alternatives to total reconstruction or asphalt overlay systems have proven their effectiveness. Several of these systems rely on installing products directly over the entire court, but attaching them only around the perimeter. This type of installation method allows the existing cracks, or future cracks, the ability to move without reflecting through the overlayment system, thus eliminating crack problems on the surface. (See “Tennis Court Crack Repair Alternatives” below.)
Keep in mind that quality design and construction may minimize or delay cracking, but it can’t completely eliminate it. Once cracks appear, it may be impossible to repair their cause, but it is not impossible to repair the crack itself and to better maintain the court from total deterioration.
Tennis Court Crack Repair Alternatives
There are a number of methods and products available to repair pavement cracks. The short-term and long-term repairs listed here are ranked from least expensive to most expensive. (Chart provided by Armor Crack Repair System.)
|Crack Fillers and Caulks||Material is poured, troweled, or caulked into the crack to fill the void. Designed for temporary repairs between normal resurfacing intervals.||Very inexpensive, but only a quick, short-term fix. The flexible material is usually tinted to match the court color.||Cracks reappear almost immediately. Wide cracks can’t be filled; small cracks are too narrow to fill.|
|Fiberglass Membranes||Fiberglass fabric is glued over the crack, then the court is painted.||Inexpensive, and looks good initially.||Cracks reappear as soon as it begins to get cold. May delaminate from the surface, causing a tripping hazard.|
|Armor Crack Repair System||An expandable fabric is applied over the crack to absorb movement without tearing or delaminating. Covered by typical color coating material.||Good for long-term repair, without spending three to five times more money. No machinery required.||May hear a “hollow” sound when ball bounces directly on center of repair. Does not work on cracks that emit heavy moisture.|
|Saw Cut & Asphalt Patch||An area of asphalt about a foot wide, containing the crack, is cut out. The void is then filled with new asphalt.||Sounds impressive.||Ends up being an expensive way to trade one crack for two parallel cracks.|
|Infrared Asphalt Patch||Propane is used to heat the asphalt around the crack, in an attempt to get the new asphalt to bond to it.||None.||Does not allow for movement. No long-term success.|
|Geotextile & Asphalt Overlay||Fabric is laid over the cracks and/or the entire court. New asphalt is installed over the whole court.||Can correct surface planarity problems. Very effective crack repair.||Requires access for heavy machinery and replacement of the net posts and their concrete footings.|
|Pre-Fabricated Roll-Out Surface (such as Premier Court)||A sand-filled turf or cushioned mat is installed over the entire court surface.||Hides cracks well and adds cushion to the surface. No heavy machinery or removal of the fence is required.||Not a good surface for inline skating or basketball.|
|Stone Screening & Asphalt Overlay||New asphalt is installed over a layer of small stones, which act like a bed of marbles that prevent cracks from reflecting up into the new surface.||Effective repair for existing and future cracks. It can correct both surface planarity and slope problems.||Requires access for heavy machinery and replacement of the net posts and their concrete footings.|
|Total Removal & Reconstruction||Remove the existing court and build a completely new court in its place.||Corrects surface planarity and slope problems.||The ground that caused the original surface to crack may very well cause the new surface to crack, too.|