Most roof problems don’t arrive suddenly. They build up quietly — a displaced tile here, a small gap in the flashing there — until one wet winter turns a minor repair into a full roof replacement. The good news is that most serious damage is avoidable if you know what to look for.

Here are eight signs that your roof needs attention, and what to do about each one.

  1. Cracked, Slipped or Missing Tiles

    Individual tiles can crack from impact (falling branches, weather), slip out of position as the nibs that hold them age, or simply fall away. Even one missing tile is enough to let water in. Check after storms and look for asymmetry in your roof slope from ground level.

  2. Damp Patches or Staining on Upstairs Ceilings

    Water staining on a ceiling — especially in a corner, near a chimney, or along a wall — often points to a roof leak. It might not appear directly below the entry point, as water can travel along roof timbers before dripping through. Don’t wait for this to get worse.

  3. Daylight Visible Through the Roof Boards

    If you can see light coming through your loft boards when you’re up there, water can get through too. Check your loft in daylight with the light off. Small pinpricks might be insignificant; a shaft of light suggests a problem that needs addressing.

  4. Moss or Algae Growing on Tiles

    Moss isn’t just unsightly — it retains moisture and gradually forces tiles apart as it grows beneath them. In Dorset’s damp coastal climate, moss growth can be aggressive. It’s worth treating and clearing periodically, especially on north-facing slopes.

  5. Sagging or Bowing in the Roof Structure

    A roof that looks uneven from the outside — particularly any sagging between rafters or along the ridge line — suggests structural issues. This could be rotten timbers, overloaded purlins, or failed supports. Don’t delay on this one.

  6. Blocked, Sagging or Damaged Gutters

    Gutters pull away from the fascia when they’re overloaded with debris or when the brackets fail. Water then pours down the outside wall rather than away from the building, eventually getting behind the render or brickwork. A clear, functioning gutter system is your roof’s first line of defence.

  7. Flashing Pulling Away or Cracking

    Flashing — the metal strips that seal the joins between your roof and a chimney, dormer, or parapet wall — is one of the most common sources of leaks. If it’s rusting, pulling away, or cracked, water will get in at that junction. Lead flashing lasts for decades when properly fixed; failed mortar pointing around it is a common issue.

  8. Your Roof Is Over 25 Years Old and Has Never Been Inspected

    If your property is over 25 years old and you’ve never had a roofer up there, it’s worth a check. Not necessarily because something is wrong, but because small issues caught early are cheap to fix. A general inspection typically costs £150–£250 and could save thousands.

What to Do Next

If you’ve spotted one or more of these signs, the right move is to get a roofer out for an assessment before making any decisions. Don’t be tempted to patch things yourself unless you’re confident working at height and understand how roofing systems work — a bad DIY fix can be harder to sort out than the original problem.

MNM Building Services carries out roof repairs and inspections across Bournemouth, Poole, Christchurch and the wider Dorset area. We’ll give you an honest assessment of what needs doing and what can wait.