Every winter we survey roofs where a £50 autumn fix has become a four-figure spring repair. Freeze-thaw is the main culprit: water gets into a small crack, freezes, expands, and opens it wider. Repeat that fifty times over a Scottish winter and a hairline crack in a ridge tile becomes a leak.
Here is the checklist worth working through before the weather turns.
1. Check the ridge and verge
Ridge tiles and verge mortar take the brunt of the wind. Look for cracked or missing mortar, and any ridge tile that sits unevenly. These are the defects storms exploit first.
2. Look for slipped or cracked slates and tiles
Even one slipped slate exposes the sarking beneath. From the ground, look for uneven lines in the courses or a slate that sits at a different angle. Binoculars help — a drone survey is better, because it sees the slopes you can't see from the garden.
3. Clear gutters and check downpipes
Blocked gutters overflow down the wall and into the eaves. In a freeze, standing water in a gutter can split joints and pull brackets loose. Clear them after the leaves fall, not before.
4. Inspect lead flashing and valleys
Flashing around chimneys, dormers and valleys is the most common leak point on Scottish roofs. Look for lifted edges, cracks and any patch repairs that have reached the end of their life.
5. Check the loft
On a bright day, turn the loft light off and look for daylight. After rain, look for dark staining on the sarking or damp insulation. The loft often shows a leak months before the ceiling does.
6. Deal with moss before it holds water all winter
Heavy moss acts like a sponge, keeping slates wet and adding weight. Autumn removal means the roof dries properly between showers instead of staying saturated until April.
The one rule that matters
Fix small things in autumn. Every defect on this list is cheap to repair in October and expensive to repair in February — if you can get a roofer at all in storm season.