Brown Rust Spots on Tarmac Tennis Courts

Rusty brown spots on the surface of a tarmac Tennis court have, unfortunately, become very common. These cosmetically undesirable spots on the playing surface usually do not affect play but detract from the appearance of the court. The coloured paint coatings make the spots stand out.

These spots are actually metallic metals called Iron Pyrites which contaminate the stone used to make the tarmac. The main constituent of porous tarmac is granite aggregate, bound together with bitumen, to create the material from which the court is built. Granite mined from seams in the UK can be contaminated with iron pyrites.

The moisture from rain goes through the tarmac making the Pyrite wet. The Pyrite then begins to rust. This rust stain eventually comes to the surface of the court causing the ugly brown spots.

Now there is a painting process that has been developed & designed to suppress this unsightly rust-spotting and to minimise its impact when it inevitably returns. This can be repeated each time a porous tarmac tennis court is re-painted, considerably reducing the visual impact of rust-spotting over its life span.

The process is a two stage system:

• Eliminate the current rust sports - spray apply one coat of a surface binder that has been chemically modified to react with the rust. Once this reaction has taken place, the resulting stains are fixed to the court’s painted surface and cannot migrate through subsequent paint coats.

• Inhibit future rust spots - spray apply two coats of a water-based acrylic coating that has also been chemically modified to react with and absorb the rust. The tennis line markings should also be applied with a similar modified paint.

Please do not hesitate to contact us for further details.