What to look for from inside
The first signs of a roof problem often show indoors. Damp patches or staining on ceilings and upstairs walls, flaking plaster, a musty smell in the loft, or daylight visible through the roof from inside the loft all point to water getting in. Catching these early keeps the repair small.
What to look for from the ground
From outside, look for slipped, cracked or missing tiles and slates, a sagging ridge or roof line, plant growth or thick moss, and loose or rusting flashing around the chimney and valleys. Gutters that overflow or sag, and staining running down a wall, are worth noticing too.
Why small problems grow
A roof is a system, and a single failed tile or flashing lets water into the structure behind it. Timber stays wet, rot sets in, and what started as one slipped tile ends up as damaged battens, felt and ceilings. The cost of ignoring a problem is almost always higher than the cost of fixing it.
When to call someone
If you can see damage from the ground, or you have damp showing inside, it is worth getting the roof looked at rather than waiting for the next storm. Roofs are not a safe place to inspect yourself, so leave the close look to someone with the right access and experience.