Tag Archives: vapor

Tennis Court Surfaces

What causes bubbles or blisters on a tennis court surface?

Bubbles and blisters on a tennis court surface, or other coated sport surface, are fairly common.  This is usually a result of improper tennis court construction or malfunction of the drainage system. When sub-surface water becomes excessive and is not properly drained away from the court, it can breathe through the slab in a vapor form and create hydrostatic pressure under the coatings.  This pressure builds more in weaker surface areas and creates a blister or bubble.  When the blister is raised, water vapor stretches the coating film and slowly breathes through to escape.  After most of the water pushes through, blisters usually lay back down and disappear until the next rain or precipitation event.  It’s important to note that excessive watering (sprinklers) around the court edge can also lead to blistering problems.  That being said, it’s very important to minimize accumulation of water beneath the court slab.

bubbles blisters pickleball court surface
Bubbles or Blisters on Court Surface

How Do I Get Rid of Bubbles and Blisters on a Tennis Court Surface?

In order to take care of the bubbles and blisters, long term, you will need to do some investigating.  Start by making sure any and all drains around the tennis court are free of debris or anything that would prevent proper flow of drainage water.  You may want to enlist the help of an architect or excavation professional in order to evaluate the current drainage system and see if it was installed properly, or at all.  If the court substrate is concrete, you must ensure the following:

  • Was a vapor barrier installed beneath the court when poured?
  • Are there perimeter drains that can take the water away from the court when it runs off after a rain? (Important that water is intercepted on all side of the slab, to prevent water beneath the court)
  • Was the concrete allowed to cure for 28 days, prior to coating?
  • Was the concrete surface acid etched to neutralize the alkalinity and balance the PH?
  • Were any curing compounds used on the concrete?
Court Surface Edge Drain
Surface-type drain – good for the low court edge

 

 

 

 

 

The American Sports Builders Association (ASBA) maintains construction guidelines for asphalt and concrete tennis court and sport surfaces.  Ensure that the construction of the court meets their guidelines and find out from the tennis court builder if they followed the ASBA recommendations.  This may help you figure out why the blisters are occurring.  If you are still not sure what to do, feel free to fill out the contact form on this page and we can put you in touch with a SportMaster recommended, tennis court builder.  They can perform a free site visit with you and provide feedback and estimates for repair, resurfacing, or re-construction. You can view our Engineering Specification for Athletic and Recreational Surfacing on our SportMaster site.

Tennis Court Blisters
Tennis Court Blisters
Tennis Court Surfaces

What Causes Rust Spots On A Tennis Court Surface?

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.

Rust spots on tennis and pickleball courts

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
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.