If you have spotted rust-coloured stains, cracking, flaking, or worse...crumbling concrete, on a balcony, car park ceiling, or facade, there is a good chance someone has mentioned the words “concrete cancer”. It is an alarming term, and in Perth’s coastal environment it is a common one. This article explains what concrete cancer actually is, what causes it, how to recognise it early, and, most importantly, why the way it is repaired matters far more than most building owners