Red Staining on Render: Causes and Safe Removal

By Mark Cave August 24, 2026 |

What Causes Red Staining on Render? Red staining on render is usually caused by one of two things: organic growth, most commonly red or orange algae, or mineral staining from iron, rust or metal run-off. On UK properties, the most common cause is biological staining from airborne algae colonising damp,...