The urgent ones are a displaced or rocking ridge tile, daylight through the roof seen from the loft, a sagging roof line, and water actively entering. The ones that mean book a repair soon are slipped or missing tiles, green staining down a wall from a failed gutter, and lead flashing that has lifted or split.
- A loose ridge tile is the only item here that is also a danger to people below.
- A sagging roof line is structural and needs assessing before any covering work.
- You can check most of this from the ground with binoculars in ten minutes.
- Daylight in the loft is unambiguous. Go and look twice a year.
Urgent: deal with these now
1. A displaced, rocking or missing ridge tile
The only item on this list that is a physical danger as well as a water risk. A ridge tile sits at the highest and most wind-exposed point of the building, and once the mortar bedding has perished there is nothing holding it. It is heavy, and below it are usually a path, a garden or a neighbour. An open ridge also admits water along the full length of the roof. If you can see mortar missing or a tile out of line from the ground, treat it as this week's job.
2. Daylight through the roof, seen from the loft
Unambiguous. Go into the loft on a bright day with the light off and look up. Pinpricks around a chimney or a vent may be acceptable detailing; a visible gap, a strip of light along a line, or daylight where a tile should be is not. Where there is daylight there is water in the next shower.
3. A sag or dip in the roof line
Stand well back and sight along the ridge. It should be straight. A dip between the gables, a bowed slope or the ridge line no longer parallel with the eaves suggests a structural issue — frequently a roof re-covered at some point in a heavier material than it was designed for. This needs assessing before any covering work, because re-roofing over a failing structure solves nothing.
4. Water actively coming in
Obvious, but worth including for what to do: contain it, and if a ceiling is bulging with trapped water, drill a small hole at the lowest point so it drains in a controlled way. A collapsing ceiling does far more damage than a hole you made deliberately. Photograph everything, and get into the loft during the rain if you safely can — it is the best chance you will get to see where water is actually entering.
Book soon: these get worse and more expensive
5. Slipped, cracked or missing tiles
One tile is a straightforward repair. What matters more is the pattern: a few in one area suggests a local cause, while a scatter across the whole roof usually means the nails have corroded to the point of failure, and patching will keep you busy. Count them and note where they are — that information genuinely changes the recommendation.
6. Green staining or damp patches down an external wall
Usually a gutter rather than the roof, and usually cheap to fix at this stage. A vertical stripe of growth below a gutter joint or a downpipe means water has been running down the wall for some time. Left alone it saturates the masonry, rots the fascia and eventually shows inside. This is the one most often ignored because it looks cosmetic.
7. Lifted, split or mastic-patched flashing
Flashings are the weatherproofing where the roof meets a chimney, a wall or a valley, and they cause a large share of the leaks we trace. Look for lead that has pulled out of its mortar joint, splits along a fold, or — the real tell — sealant smeared along the line. Mastic on a flashing means it has already failed and been patched rather than replaced.
The ten-minute check
- Stand across the road with binoculars and sight along the ridge. Is it straight?
- Scan the ridge and hip lines for missing mortar or tiles out of alignment.
- Look over the field of tiles for slipped, cracked or missing units, and note roughly where.
- Check the verges — the gable edges — for loose pointing or exposed batten ends.
- Look at the chimney: pots upright, flaunching intact, flashing lying flat against the brickwork.
- Walk the perimeter and look at the walls for vertical staining below gutter joints.
- Go into the loft with the light off and look for daylight, then with a torch for staining on timbers and damp insulation.
- Note anything you find with a photo. Twice a year, plus after any serious storm.
All of that is from the ground and the loft. Nothing on this list requires going onto the roof, and nothing on it is worth the risk of doing so.
Urgency at a glance
| Sign | Urgency | Why |
|---|---|---|
| Ridge tile loose or displaced | This week | Danger to people below, plus open ridge line |
| Daylight visible in the loft | This week | Water is already getting in |
| Sagging roof line | Assess now | Structural; changes the whole scope |
| Active leak | Now | Damage continues with every shower |
| Slipped or missing tiles | Weeks | Underlay now exposed to direct weather |
| Staining down an external wall | Weeks | Usually a gutter; cheap now, not later |
| Failed or mastic-patched flashing | Weeks | A common leak source already patched once |
| Heavy moss | Next dry spell | Holds water, blocks valleys and gutters |
What it is likely to cost
Most of what is on this list is at the cheaper end if caught early. These are the roofing figures published across this site:
| Job | Typical Coventry guide price | Notes |
|---|---|---|
| Minor roof repair | from £150–£400 | Slipped or broken tiles, usually one day |
| Chimney repointing / flashing | £300–£900 | Access dependent |
| Full re-roof (typical semi) | £5,000–£9,000 | Strip, membrane, batten, re-tile |
| Larger / detached re-roof | £9,000–£12,000+ | Scaffolding included |
The expensive outcomes on this page are the ones left long enough to wet the timber and the ceiling. A ridge re-bedded is a small job; the same defect after three winters is not.
We will tell you over the phone whether it needs attention this week or can wait for a planned visit.
Frequently asked questions
How can I check my roof without going up there?
Binoculars from across the road will show you the ridge line, missing mortar, slipped tiles, the state of the verges and whether the chimney flashing is lying flat. Then the loft with the light off, looking for daylight, and with a torch for staining and damp insulation. That covers almost everything on this page safely.
Is a loose ridge tile dangerous?
Yes, and it is the one item here that is a danger to people as well as a water risk. A ridge tile is heavy, sits at the most wind-exposed point of the building, and once the mortar has perished nothing is holding it down. Below it is usually a path or a garden. Treat it as urgent rather than seasonal.
What does a sagging roof mean?
Usually a structural issue, and most commonly a roof that was re-covered at some point in a heavier material than the timbers were sized for — typically slate replaced with concrete tiles. It needs assessing before any covering work, because laying a new roof over a failing structure does not address the cause.
Should I worry about moss on my roof?
It is not an emergency but it is not harmless either. Moss holds water against the tiles, which matters in frost, and it breaks off to block valleys and gutters — which is where the real damage comes from. Have it removed by scraping and brushing, never by pressure washing, which damages the tiles.
How often should I check my roof?
Twice a year, and after any serious storm. Ten minutes with binoculars and a torch in the loft is enough to catch almost everything on this page while it is still cheap. The jobs that become expensive are the ones that went unnoticed for several winters.
Can I just leave one slipped tile?
For a short while, but not indefinitely. The gap exposes the underlay to direct weather and UV, which shortens its life precisely where it matters, and the displaced tile can slide further and fall. If it is above a path, a door or a conservatory, deal with it sooner for safety rather than for water.
Ten minutes now, or a ceiling later
If you have spotted something and are not sure how urgent it is, call and describe it. We will tell you honestly whether it needs us this week.