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.

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.