Slipped Tile: Urgent Or Can It Wait Until Spring?

Key takeaways

• A single tile out of place on a large slope with sound underlay beneath is rarely urgent.
• A tile that has slid down and is resting in a gutter or on a lower course is a falling hazard and changes the answer.
• Tiles near a valley, a hip or the eaves matter more than tiles in the middle of a slope.
• One tile slipping is often the first visible sign of a wider problem, so what caused it matters more than the tile.
• Leaving it through a winter usually turns a single tile job into several.

What holds a tile in place, and why it lets go

Most concrete and clay tiles are hung on battens by a nib on the back, and only a proportion of them are actually nailed, typically the perimeter courses and every third or fourth tile elsewhere. Gravity and the weight of the tile above do the rest. So a tile slips when its nib breaks, when the batten behind it has rotted or split, when a nail has corroded through, or when something has knocked it. On a slate roof there are no nibs at all and every slate is nailed, so slipping there means the nails or the batten have failed rather than the slate. That distinction matters: a slipped concrete tile is often an isolated event, while a slipped slate is frequently the first of many.

Question one: has it left a gap in the covering

Look at where the tile was rather than where it now is. If the tile has slid down but the tiles either side and the course above still overlap the opening, the roof may still be shedding water reasonably well. If there is a clear rectangular gap showing a darker surface beneath, the covering is open at that point and the underlay is now the only thing keeping water out. On a roof built in the last twenty five years that underlay is probably a breathable membrane in good order, and it will cope for a while. On a roof of sixty years or more the felt underneath may be brittle or already torn, in which case there is effectively nothing between the gap and your loft.

Question two: where has it slipped from

Position changes the answer more than most people expect. A tile missing from the middle of a large plain slope is the least serious version, because water there is doing what it does everywhere else on the roof and the underlay carries it away. A tile displaced beside a valley is far more serious, because valleys concentrate water from two slopes and a gap next to one puts a large volume through it. The same applies at the eaves, where all the water from the slope above passes, and around a chimney or roof window where the detail depends on the tiles sitting exactly where they were laid. A slipped tile at a hip or ridge is also a structural question rather than only a watertightness one.

Question three: can it fall on anybody

This is the question that overrides the other two. A concrete tile weighs several kilograms and a roof is high enough to make that dangerous. If the tile has slid and is now resting on the course below, wedged in a gutter, or sitting proud at an angle, treat it as urgent regardless of whether anything is leaking, particularly if it is above a path, a doorway, a pavement, a driveway or a garden anyone uses. Tiles that have moved once tend to move again in the next strong wind. If it is above a public footpath, the responsibility for what it lands on is yours, and that is a good reason not to wait for a convenient week.

What actually caused it, which matters more than the tile

A single tile failing on a young roof is usually mechanical: a knock from a ladder, a branch, a passing bird strike, or a nail that was never quite right. A tile failing on an older roof is usually a symptom. Battens rot from the top down where water has been getting past for years. Nails corrode when moisture has been present. Nibs snap when the tile has been under stress from a slope that has moved. So the useful question when somebody comes to put it back is not just whether the tile is secure now, but whether the batten it hangs on is sound and whether its neighbours are showing the same early signs. One tile refixed onto a rotten batten is a repair that will be needed again.

Looking at it properly without a ladder

Take a photograph from as far back as you can get, using full zoom, from two or three different angles including from the neighbouring side of the street if you can. Compare the suspect area against an identical stretch of roof further along, because roofs are repetitive and anything genuinely wrong stands out against its own pattern. Look for other tiles sitting slightly out of line, for tiles with visible cracks, and for a wavy line along a course, which suggests the batten behind has dropped. Check the ground and the gutters for fragments, because pieces of tile in a gutter tell you something has already broken up there. Never go up to look, and be wary of anyone who knocks at the door offering to take a look while they are passing.

The honest answer on timing

If it is one tile, in the middle of a slope, on a roof under about forty years old, with nothing loose and nothing overhead that can fall on a person, then it can reasonably wait for a planned visit and there is no need to pay emergency rates. That is a common and legitimate outcome. Bring it forward if there is a clear gap and the roof is old, if it is near a valley, chimney or the eaves, if more than one tile has moved, or if anything is sitting loose. Do not leave it across a winter in any case: freeze and thaw works on the exposed edges of whatever is now uncovered, and wind gets under a disturbed course far more easily than an intact one.

What the repair should include

Refitting a slipped tile is a small job, and the value is in what gets checked while somebody is up there. The batten should be inspected and replaced if soft. The tile should be mechanically fixed rather than simply dropped back into position, since a tile that slipped once has already demonstrated that gravity alone was not enough. The underlay beneath the gap should be looked at, because a tear there is the difference between a covered roof and an open one. And the surrounding tiles should be checked for the same fault. Expect a modest cost dominated by access rather than materials, which is the argument for combining it with anything else outstanding on the same roof.

Frequently Asked Questions

Is one slipped tile an emergency?

Usually not. A single tile in the middle of a slope on a reasonably modern roof, with sound underlay beneath and nothing loose overhead, can wait for a planned repair. It becomes urgent if the tile is resting somewhere it can fall, if it is beside a valley or chimney, or if the roof is old enough that the underlay may already have failed.

Will one missing tile cause a leak?

Not immediately in most cases, because the underlay beneath is designed to catch what gets past the covering. How long you have depends on the age and condition of that underlay. On a modern breathable membrane you have a reasonable margin. On perished bitumen felt there may be no margin at all.

Why do tiles slip in the first place?

Because most tiles hang on a batten by a nib and only some are nailed. A tile slips when the nib breaks, the batten rots or splits, a nail corrodes, or something knocks it. On a slate roof, where every slate is nailed, slipping usually means the nails or battens have failed, which tends to affect more than one slate.

Can I put the tile back myself?

It is not worth the risk. Falls from height are among the most common causes of serious injury in home maintenance, working on a pitched roof needs proper access, and standing on tiles breaks more of them. The job itself is small enough that the saving does not justify what can go wrong.

Should I be worried if more than one tile has slipped?

Yes, treat that differently. Several tiles moving in the same area points at the battens or the fixings rather than at the tiles, which means the cause is spread across the roof rather than confined to one spot. That is worth a proper inspection rather than three individual repairs.

The tile fell into the gutter. Does that matter?

It does, on two counts. It is a weight sitting somewhere it can fall from, and it will obstruct the gutter and cause overflow in the next heavy rain. Retrieving it and clearing the run should be part of the same visit as refitting the covering.