Seven signs your roof needs attention (and three that can wait)

Roofs rarely fail all at once. They fail slowly, in one small place, for a long time before anyone notices — and then they appear to fail suddenly, usually during the first proper storm of the autumn.

The good news is that most of the early warnings are visible from the ground with nothing more specialised than a pair of binoculars. Here is what we look for, roughly in order of how urgently it needs dealing with.

The seven that need attention

1. Slipped, cracked or missing tiles

The most obvious sign and the most commonly ignored. A single slipped tile is not an emergency, but it exposes the felt beneath to direct weather and UV, and felt degrades quickly once uncovered. Left through a winter, one tile becomes a patch of perished underlay.

Before

After

2. Failed or missing mortar on the ridge

Ridge tiles were traditionally bedded on mortar, which has a working life of perhaps 20 to 30 years before it cracks and loses its grip. Crumbling mortar along the ridge line is both a leak path and a genuine safety issue — a loose ridge tile in high wind is dangerous.

3. Daylight through the loft

Go into the loft on a bright day with the light off and give your eyes a minute to adjust. Pinpricks of daylight through the roof structure mean a genuine gap. This is the single most reliable check available to a homeowner.

4. Damp, staining or water marks on loft timbers

Dark patches, white salt bloom or a musty smell in the loft all point to water getting in. Worth distinguishing from condensation, which is a ventilation problem rather than a leak — condensation tends to be even across a whole surface, whereas a leak stains in a run or a patch.

5. Sagging along the roof line

Sight along the ridge from the far side of the road. It should be straight. A visible dip suggests something structural — a failed purlin, spreading rafters, or timbers softened by long-term water ingress. This one is genuinely urgent.

6. Granules from the roof collecting in gutters

On felt shingle and some concrete tiles, a build-up of coarse grit in the guttering means the weathering surface is breaking down. A little after new work is normal; a steady accumulation year on year is the roof telling you it is near the end of its life.

7. Damaged flashing around chimneys and valleys

Most leaks we trace are not through the tiles at all — they are at a junction. Lead flashing around chimneys, in valleys and at abutments does the hardest work on any roof, and it is where we look first when a leak has no obvious source.

And three that can usually wait

• Moss growth on its own. Moss looks untidy and holds moisture, but on a sound roof it is cosmetic. Scraping it off aggressively does more harm than leaving it — it takes the weathering surface with it.
• Minor discolouration or patchy weathering. Tiles fade unevenly depending on aspect and shelter. Uneven colour is not a fault.
• A single cracked tile low on the pitch with sound felt beneath. Worth putting on the list for the next visit, but it is not letting water into the building today.

Repair or replace?

This is the question everyone actually wants answered, and any roofer giving you a firm view without having been up there is guessing. As a rough guide, though:

The trap worth avoiding is repeated patch repairs on a roof that has genuinely reached the end of its life. Three call-outs in two winters usually costs more than doing the job once and properly.