My roof leaks, do I repair it or replace it?

Most roof leaks are not the roof failing. They are a discrete component failing, and the water then travels, sometimes a long way, before it appears on a ceiling. That is why the stain on your ceiling is often nowhere near the actual entry point, and why a roofer who quotes a full replacement without investigating is worth a second opinion.

Where leaks usually originate

• Flashings, especially where the roof meets a wall, a chimney or a penetration. This is the most common source by a wide margin.
• Valleys that have rusted through or filled with debris.
• Cracked or slipped tiles, and failed pointing on ridge capping.
• Blocked gutters causing water to back up under the roof edge.
• Failed sarking beneath the covering, which turns a minor entry into an internal leak.

Points to replacement

• Widespread rust perforation on a metal roof, rather than isolated spots.
• Tiles that are delaminating or breaking underfoot across the roof, so every repair creates new damage.
• Repeated leaks in different places over a short period. A pattern, not an event.
• Battens or structure showing rot, which must be dealt with regardless of the covering.

Note that roof plumbing (gutters, downpipes and stormwater) is licensed plumbing work in most states, which is a separate credential from general roofing.