‘Rust or orange-coloured ‘iron break-out’ can appear naturally within hard ferrous-type stone pavers, like sandstone, slate and granite. These stones naturally contain iron which can oxidise or rust when it comes into contact with rain. Washing ferrous stone with excessive amounts of water can also cause this reaction, as can certain acidic cleaners, like brick acid and cement removers which can accelerate oxidisation. Ironically, these same products are often used to remove rust marks and can create an even greater problem.

It’s not possible to completely halt oxidisation because it arises from within the stone. However, protecting the stone with a sealer – like a natural finish stone sealer or an external paving and stone sealer – can help stop the acceleration caused by rain and water. Stains can also be removed using a treatment that’s formulated for internal rust. We recommend an iron stain away, a professional treatment that safely removes rust outbreaks from unpolished ferrous hard stones, including sandstone, slate and granite, as well as cement and mortar stains. Mark Atkins, director