Most roof problems start small and get expensive. A slipped tile becomes a leak. A leak becomes damp. Damp becomes rot. Here are the signs that mean you need a roofer — before it costs thousands.
1. Water Stains on Ceilings or Walls
The most obvious sign. Brown or yellow patches on your ceiling mean water is getting in. The stain might be metres from the actual leak — water travels along joists and surfaces before dripping.
What to do: Don't wait. A small stain means water has already been entering for weeks. Check your loft (if you have one) for wet patches or mould, then call a roofer.
2. Tiles on the Ground
After wind or storms, check your garden. One or two tiles might be normal after a severe storm. More than that, or tiles appearing regularly, means your roof is deteriorating.
What to do: If you see tiles on the ground, someone needs to check the roof. A missing tile exposes the felt and battens — which degrade quickly when wet.
3. Daylight Through the Roof Boards
Go into your loft during daylight. Turn off any lights and look for daylight coming through the roof. If you can see light, water can get in.
What to do: Pinhole gaps might be acceptable in older roofs (they dry out). Large gaps, missing tiles, or damaged felt needs repair.
4. Sagging Roofline
Stand back from your house and look at the ridge line. It should be straight. If it dips, sags, or curves, you have structural problems — probably rotting timbers.
What to do: Call a roofer or structural surveyor immediately. A sagging roof can collapse. This is not a DIY repair.
5. Moss and Algae Growth
Some moss is normal. A lot is a problem. Moss holds water against your tiles. When it freezes, it expands and cracks the tile surface. Heavy moss also blocks drainage channels.
What to do: Have the roof cleaned professionally. Don't pressure wash — it damages tiles. Brush treatment or chemical cleaning is gentler and lasts longer.
6. Damaged or Missing Flashing
Flashings are the metal strips around chimneys, vents, and valleys. They prevent water getting through gaps. If flashing is cracked, lifted, or missing, water enters where the roof meets vertical surfaces.
What to do: Check from ground level with binoculars if needed. Damaged flashing should be replaced promptly — it's a common leak source.
7. Cracked or Crumbling Mortar
Ridge tiles and verges (the edges) are held in place with mortar. Over time, mortar cracks and crumbles. When it fails, ridge tiles slip and water enters through the gaps.
What to do: If you see mortar on the ground or cracks visible from ground level, the ridge needs repointing. This is straightforward maintenance but should be done before tiles slip.
Other Warning Signs
- Damp in the loft: Felt or insulation feels wet, or you smell mould
- Dripping sounds: After rain, check for water movement in the loft
- Cracks in internal walls: Near the ceiling — may indicate roof movement
- Doors sticking: If doors near the top floor stick, the frame may be warping from roof issues
- Higher energy bills: Wet insulation doesn't work — your heating works harder
When to Call a Roofer
Call a professional if you notice:
- Any water entering your home
- Multiple missing tiles
- Sagging or structural issues
- Daylight through roof boards
- Damp or mould in the loft
For annual maintenance, have your roof inspected every 2–3 years. Prevention costs far less than repair.
What a Roofer Will Check
- Tile condition (cracked, slipped, missing)
- Ridge and verge mortar
- Flashing around chimneys, vents, and valleys
- Felt condition (from inside the loft)
- Gutter condition and drainage
- Chimney stack and pots
- Flat roof membranes (if applicable)
The Cost of Waiting
| Problem | Repair Cost (Early) | Repair Cost (Late) |
|---|---|---|
| Slipped tile | £80–£150 | £500+ (water damage) |
| Flashing failure | £200–£400 | £1,000+ (internal damage) |
| Flat roof leak | £200–£500 | £2,000+ (rot and replacement) |
| Sagging roof | Assessment £200 | £5,000–£15,000 (structural repair) |
Why DNDH for Roof Inspections
DNDH Construction provides roof inspections across Cambridge and Cambridgeshire. We check everything from ground level and inside the loft, give you a clear report, and only recommend work that's actually needed.