The short answer
It can be. A ridge tile is a heavy curved tile capping the top of the roof, and one that has slipped may drop onto a drive, a bike or a passer-by. If it is still holding but out of line, it is urgent rather than an emergency. Stay off the roof, keep the ground below clear, and have a roofer look at it soon.
A ridge tile that has shifted is a falling-object risk first and a leak risk second. Both are worth dealing with before the next gale arrives.
Why a slipped ridge tile matters
Ridge tiles cap the join at the top of the house, where the two slopes meet. Each is set in a bed of mortar or held down with clips and screws. When that bedding fails, a tile can turn, drop out of line or slide towards the edge of the roof.
Could it actually fall?
Yes. A ridge tile is heavy and the drop from the top of a house is long. Among its examples of dangerous structures, Somerset Building Control includes "Loose or falling roof tiles". It adds that making a dangerous building safe is paid for by its owner, which is why a slipped tile should not be left.
That is the reason to treat a slipped tile with care. It is also a leak risk, because the gap below an out-of-line tile lets rain run into the loft. The two problems share a cause, and our page on why ridge mortar cracks explains how a tile ends up loose in the first place.
What to do straight away
Start from the ground. Look at the crest from the lawn or the street, and note where the tile has moved and whether others near it have shifted. Take a photo if you can do so safely, using the zoom rather than going closer. Note the date and the weather, since both help when the repair is planned.
Should I go up and push it back?
No. The very top of the house is its most exposed spot, and a slipped tile may have nothing holding it. Pushing it back risks your balance and may knock the tiles beside it loose. Leave it to a roofer who works from a tower or roof ladder with proper edge protection.
Move people and pets away from the ground below, and shift a parked car if it sits under the ridge. If a tile has already fallen, pick up the pieces carefully and keep them, since they help us match the replacement. If water is coming through the ceiling, say so when you ring, because stopping the leak comes before any tidying. If the ridge sits above a public path or a neighbour's gate, tell the neighbour too.
Emergency, urgent or can it wait?
A tile that has fallen, or one hanging at an obvious angle above a path, calls for a quick make-safe. A tile that has slid a few centimetres but sits firm is urgent, and worth fixing before the next stormy spell. A tile that looks merely uneven but does not rock can be assessed at the survey.
How is a ridge tile made safe?
The loose tile is lifted off or refixed, and any others that rock are checked by hand along the run. A tile that has cracked is replaced rather than bedded back down. If the cause is cracked bedding, the section is re-bedded and fixed mechanically. If it is a dry ridge unit, the clip or screw is replaced and the batten checked for soft timber. A broken tile is swapped for a matching one, and we show you the new fixing in a photo.
If the fault has damaged the home, let your insurer know first, get a temporary repair done, and keep every photo and receipt in one folder. The insurer decides the outcome of any claim. Our overview of dry ridge and verge work covers the repair routes, and the page on re-bedding ridge tiles shows the usual fix in detail.
Finding the cause so it does not happen again
One slipped tile is often the first of several. Mortar that has let go on one side of the crest may be weak along the whole run, and a gap of a few millimetres is enough to start a slide. Wind may have lifted the tile, or a heavy frost may have helped it along.
Why did only one tile move?
The line is only as strong as its weakest bedding. Wind and rain find the loosest tile first, and once it shifts, the load goes to its neighbours. We tap and test each tile along the run, then photograph any that move, so you see the whole crest and not just the one you noticed. We also look at the ends, where the ridge meets a hip or a gable, because tiles there carry extra load.
If the bedding has cracked widely, a new dry ridge may be the better buy than patching mortar again. Our page on dry ridge failure explains what to check where a dry system is already fitted. After the survey you get one total in writing, covering whichever repair the roof needs.
More on slipped ridge tiles
Is it safe to leave a slipped ridge tile for a week?
If it is firm and only slightly out of line, a short wait is reasonable, but keep the ground below clear and watch the forecast. If wind is due or the tile rocks, do not wait. A tile in motion is a risk to anyone beneath it.
Can I stand a ladder against the roof to check it?
A ladder helps you see, but the top of the house is high and exposed, and the ground below may be uneven. Use binoculars or a phone zoom from the ground instead. If you need access, leave it to a roofer who can set up a proper tower or roof ladder.
The full picture: Dry ridge and verge repairs in Taunton ยท More short answers