What signs show a roof needs repairing?

Begin outside, at ground level, with binoculars if you own a pair. Scan for tiles sitting lower or higher than their row, gaps where one has gone, and chips or cracks across a face. Follow the ridge, the line right at the top, for tiles that lean or mortar that has crumbled. Check the lead or mortar where the roof meets the chimney, because a strip that has lifted or split lets water in behind it.

Gutters talk too. Grit washed off the tile surface, a thick growth of moss in the channel, or water pouring over the lip in a downpour all hint that the roof or the gutter wants attention. After a gale blowing in off the sea, walk round the house again, since slipped tiles often drop onto a lean-to roof or into the border. A little heap of broken tile in the flowerbed is a clear message that something up above has let go.

The mark overhead is the clue that gets noticed first. Look for a ring-shaped tide mark, darker at its rim, paint that bubbles or flakes, and a patch that spreads after heavy rain; each suggests water is getting in. Walls count as well. A damp stripe beside a chimney breast, or a mark near the top of an outside wall, can lead back to flashing or a gutter outlet.

Not every mark is a roof leak. Black spotting in a cold corner, or wetness that shows on frosty mornings, is often condensation, and a pipe or cistern can leave a stain of its own. Our answer on whether a damp patch on the ceiling comes from the roof explains how to separate the three, while the guide to finding a roof leak follows the route water takes once it gets in.

Go up on a dry day with a decent torch and stand on the joists or on a board, never on the plasterboard between them. Look for pinpricks of daylight through the covering, timber that is dark or stained, insulation that has flattened or gone wet, and drips running down a rafter. Rafters or battens that sag, the thin timber strips carrying the tiles, deserve a photograph.

Underlay is the sheet of felt or plastic membrane stretched under the tiles as a second barrier. If it has torn or slid out of place, or you can see tiles resting on bare timber, the roof is working harder than it should. Note what you saw and where, taking the front of the house as your reference point, so that a roofer can go straight to the spot instead of hunting for it.

One slipped tile means a modest visit. A scatter of them over one slope usually means something else is going on. Several in a row often trace to nail sickness, where the fixings holding the tiles have corroded or worked loose, and our page on nail sickness explains what that means for the roof as a whole.

A dipping ridge, a belly in a slope, tiles that flake when touched and leaks that return after every repair all suggest the covering or the timbers underneath are tired. This is where a plain verdict matters most. Ours is a ruling on your own roof, shown with its photographs: fix it, make do for the moment, or renew it. Where a fix will last, you will be told so, with the reasons. Our comparison of whether it is cheaper to repair or replace shows how that call is reached.

Photograph the sign, dated, from wherever you can stand safely. Resist the temptation to put a ladder up for a closer look: the surfaces are slippery and the edges have no protection. If rain is getting through, put a bowl under it, shift furniture clear and ring us, so the roof can be made safe first. Anything actively leaking is dealt with ahead of everything else we have booked.

If a storm did the damage, tell your insurer as well, and read our answer on whether to call a roofer or your insurer first. A single gap has its own page: one missing roof tile. Pictures from the survey reach you plus a priced quote in writing, one total at the bottom, and the visit itself is described on the roof repair survey visit page. The full service sits under roof repairs.