Repairing roofs is the entire business here. It is not a route into selling you a new one. Croydon is an unusual borough to roof in: it runs about four hundred feet uphill from the Victorian terraces at Thornton Heath to the chalk ridge at Kenley and Sanderstead, and a roof at one end of it has almost nothing in common with a roof at the other. What fails, and why, changes as you climb.