What roof damage actually looks like

Fix soon

A tile that has slid out of its course, or gone altogether, leaves the underlay exposed to direct rain and UV. Scottish underlay rarely lasts long once it is uncovered, so a single slipped tile is a small job that turns into a big one if it is ignored over a winter.

Plan a repair

Ridge and hip tiles on older roofs are bedded on sand-and-cement mortar. Mortar is rigid, the roof moves and the weather freezes and thaws — so over 15 to 25 years the bedding cracks, crumbles and eventually lets ridge tiles go.

Fix soon

Hail damage is the defect people miss most often, because the roof looks intact from the pavement. What actually happens is impact bruising and micro-cracking that lets water in, then freeze-thaw finishes the job over the following winters.

Plan a repair

Gutters are the cheapest part of a roof to maintain and the most expensive to ignore. Once a run is blocked or has dropped off its fall, water spills down the wall instead of into the downpipe — and wet walls turn into internal damp.

Urgent

Most roof leaks are not holes in the roof — they are failures where the roof meets something else. Lead flashing at a chimney, abutment wall or valley is the usual culprit, and it fails long before the surrounding tiles do.

Monitor

A film of moss on a north-facing slope is normal in Scotland and largely cosmetic. Thick growth is a different matter: it holds water against the tile surface, blocks drainage paths and washes into gutters where it forms a dam.

Fix soon

A flat roof is never truly flat — it is laid to a shallow fall so water runs off. When water still sits there 48 hours after rain, either the fall has been lost through deck deflection or the outlet is not doing its job.

Fix soon

The chimney is the most exposed masonry on the building and the hardest thing to inspect without scaffolding. It is also, along with flashings, one of the most common sources of persistent damp in an upstairs room.