A ridge tile rarely lets go without warning. The mortar under it cracks, the joint opens, the tile starts to move a few millimetres each winter, and then one stormy night it slides off and lands on the lawn. The warning signs are usually visible for months before that, if you know where to look. This guide takes you through them in the order you would meet them: first what can be seen from the ground, then what shows up inside the house, then what the loft tells you. None of it needs a ladder, and none of it should be tried from the roof itself.
Start from the ground
Stand back far enough to see the whole ridge line, ideally across the road or at the bottom of a long garden. A pair of binoculars turns a vague impression into something you can describe. Walk along the length of the house and look at each section in turn, because the north side of the roof and the gable ends usually age first.
A line that is no longer straight
A healthy ridge sits in a clean, level line. If you can see a tile sitting proud of its neighbours, tilted to one side, or pushed along the ridge so that a joint is wider than the rest, the bed beneath it has failed. A slight sag where the ridge meets a chimney or a gable can mean the tile there has dropped as the mortar crumbled.
Cracked, powdery or missing mortar
The joints between ridge tiles should be solid and slightly recessed. Mortar that has turned pale, grainy or sandy has lost its binder. Fine cracks that run along the bed where it meets the tile are the first stage. Open gaps and hollows are the second. Where the mortar has fallen away you may see a dark void or the edge of the roof tile below.
Debris on the ground and in the gutters
Grit, orange or grey crumbs and small chips of mortar in the gutters, on a flat roof below or on a path are a plain clue. They came from somewhere. If the gutter outlet at the ridge end of the house keeps filling with crumbled cement, the ridge above is shedding it.
Moss, lichen and plant growth along the line
Moss on a roof is common and not a fault by itself. Along a ridge, though, it can show where water is held against the mortar, and a plant growing out of the bed itself means the joint is open enough to take root. Our page on moss, gutters and drainage explains how growth and blockages feed each other.
What it looks like from inside the house
Water that gets in at the ridge runs down the underside of the roof and shows up in places that seem unconnected to the top of the house.
Look for brown or yellow rings on the bedroom ceiling that grow after rain or a wet week and fade in dry weather. Look for blistering or peeling paint on the upper part of a ceiling near an outer wall, and for a musty smell on the landing. A damp patch directly under the ridge line is the clearest, but water can track along rafters and appear a metre or two away. If the stain is dry when you touch it and does not grow, it may be old. If it is cold, soft or darker at the edges, water is still arriving.
Be careful not to jump straight to the ridge. Flashings, slipped tiles, gutters and condensation can all produce similar marks. Our walk-through of how a roof leak is traced and mended shows how a roofer traces a leak, and the page on a roof leaking with no visible damage covers the cases where the cause is not obvious.
What the loft shows
The loft gives the most honest view of the ridge, because you see the underside of the work. Go up on a dry day with a torch, stay on the joists or a safe boarded area, and look along the ridge board at the top of the roof.
Pinpricks of daylight along the ridge mean there is a gap in the covering. Dark stains on the ridge board, the tops of the rafters or the underside of the felt show that water has been getting in. Black spotting can be mould from damp, which is sometimes from the leak and sometimes from condensation, a different problem covered in our guide to ridge ventilation and condensation. Rusty nail heads, bleached or lifting felt at the ridge, and insulation that is stained or matted below the ridge are further signs.
Loose mortar can also drop through gaps in the felt and lie on the insulation or the ceiling boards. Small heaps of grit below the ridge are worth noting down and photographing.
Sound and wind
Some failures announce themselves in a gale. A ridge tile that is moving can rattle, scrape or click in strong winds. A tile that rocks every time a gust hits is no longer fixed to anything. If you hear it, make a note of the time and the wind direction and look at the ridge in daylight. Do not climb to investigate.
If a dry ridge or dry verge is fitted, a rattle can come from a loose cap or a missing fixing and not from failed mortar. Our answer on whether dry verges rattle in the wind explains the difference.
| Sign | Where you see it | How urgent |
|---|---|---|
| Pale, sandy, crumbling mortar | Ground, with binoculars | Plan a survey soon |
| Tile out of line or tilted | Ground | Survey within weeks |
| Tile rocks or rattles in wind | Ground or inside | Prompt attention |
| Daylight along the ridge | Loft | Survey soon, water can enter |
| Stain growing on ceiling | Upstairs ceiling | Prompt attention |
| Tile fallen or missing | Ground | Make safe first |
Hips, verges and dry systems have their own tells
The signs above apply to the main ridge, but the same roof has other lines that fail in a similar way. A hip tile runs down the slope at an angle, so when its bed fails it tends to creep downhill. Look for a gap opening at the top of a hip, a tile whose lower end has slid past its neighbour, or a hip iron (the metal bracket at the foot of a hip) that has rusted or pulled away. At the gable, the verge is the sloping edge of the roof, and its signs are cracked fillets, lifting end tiles and brick stains below.
On a dry-fix ridge the picture changes. There is no mortar to crack, so failure shows up as a cap that has shifted, a screw head that has backed out, a clip that has snapped, or a vented strip that has lifted at the end. Rattling is more likely than crumbling. Because dry systems are made of several parts, a missing end cap can look small from the ground and still let birds, wind and rain into the system.
Seasons and the way damage shows
Roofs tell different stories at different times of year. After a hard frost, water that has crept into a cracked joint expands and widens it, so you may notice new gaps in February that were not there at Christmas. After a dry summer the mortar may shrink and open fine cracks along the bed. In autumn, wet leaves and debris collect against a rising tile, and in spring a clean look from the ground after the winter gales is the best moment to spot anything that has moved. If you only check once a year, check then.
Why ridge tiles fail in the first place
Knowing the cause helps you judge what to do. The most common reason is simple weathering: mortar is a thin, porous bed on the most exposed part of the roof, and it breaks down with freeze and thaw. Our answer on why ridge tiles come loose goes through the causes one by one. Poor original work contributes as well. A bed laid too thin, with no mechanical fixing, or too wet a mix, gives up early. Roof movement adds to it, as does impact from a branch or a ladder against the ridge.
Age matters more than people expect. A ridge that was bedded properly can last for many winters, but nothing on a roof lasts for ever. The question is not whether to look at it, but when.
What to do when you spot something
Take photographs from the ground and, if you can reach it safely, from an upstairs window. Write down when you first noticed the sign and what the weather was doing. If water is coming in, put a bowl or bucket under the drip and move valuables, and if a tile has fallen, keep people and pets away from the area beneath the ridge. Do not climb up to push a tile back. Mortar at height is dangerous to work with and a fall from a roof is far worse than a leak.
A fallen tile can leave the felt exposed to rain and wind-lift, and the nearby tiles may be about to follow. Our page on what to do if a ridge tile fell off sets out how to judge urgency. For loose mortar without a leak, a survey in the next few weeks is sensible. Insurance can be a separate question, which we cover in our answer on whether home insurance covers loose ridge tiles.
What a survey adds
From the ground you see the symptoms. On a survey we go up and look at the cause. We check whether the tiles are bonded or rocking, lift a small sample of mortar to see what lies beneath, look at the ridge board and the felt, and photograph each section, so you see what we see. The answer may be a few joints of re-pointing, a re-bed of one run, or a rebuild of the whole line. Our guide to re-pointing vs re-bedding ridge tiles sets out how that decision is made.
You get a photographed report and one fixed written quote. Where a repair will hold, we recommend it and leave out the work you do not need. Anything we rebuild is covered by our ten-year workmanship guarantee in writing. If you would like a closer look at your own ridge, see ridge tile repairs in Basingstoke where the visit is free and the number is 01256 213956, with WhatsApp open as well.
