Can loose ridge tiles cause a leak?

How water gets past a ridge

The ridge is the line of capping tiles at the apex where two slopes meet. Underneath it, the two slopes stop short of each other, and the gap between them is closed by ridge tiles. On a traditional roof those tiles are bedded in mortar. On a newer or reworked roof they may be held by a dry-fix system, which means mechanical clips, straps and a ridge board rather than a wet bed of mortar.

A ridge does not normally take much water straight down onto it, because it is the highest point. The trouble comes sideways. In a gale, rain is driven up the slope and across the top, and a gap under a ridge tile lets it travel inward. Water also finds its way in through cracks in the mortar joints between tiles, and through the open ends of a ridge, where the bedding against the gable wall has fallen away.

Once past the tile, water lands on the top edge of the underlay, the felt or membrane that sits beneath the tiling, and on the head of the rafters. The tiles themselves hang from battens, the small-section laths nailed across the rafters. If the underlay is old, torn or stopped short of the ridge, there is nothing to catch what comes in, and the water runs down the rafters or drips onto the loft insulation.

Where the leak shows inside the house

A ridge leak rarely appears directly beneath the gap. Water follows timber, so it tends to travel along a rafter or the ridge board before it falls. A stain on an upstairs ceiling may be a metre away from the broken tile, which is how people end up repairing the wrong place first.

These are the signs we look for from inside the loft and below it.

• Dark streaks on the rafters near the ridge. Tide marks where water has run down the timber and dried, repeated over several storms.
• Damp or compressed insulation at the apex. Insulation that is wet at the top of the loft, with dry material lower down, points to water entering high up.
• Staining on the ridge board itself. The board that runs along the apex shows dark patches or soft spots where it has been repeatedly wetted.
• Brown rings on a top-floor ceiling. These appear after the water has soaked through the plasterboard, usually after sustained or wind-driven rain.
• Daylight along the apex. Light seen from the loft along the top line means the gap is open to the sky.

Because the water has so far to travel, the damp in the roof space can be well established while the rooms below still look fine. A look in the loft after a spell of rough weather is the quickest way to catch it.

What loosens a ridge in the first place

Mortar is hard but brittle. Over many winters it takes in water, freezes, expands and breaks away. Once it cracks, the tile it holds can rock under wind, and a rocking tile breaks the rest of the bedding around it. A mix that is too strong for the tiles and the roof movement beneath them can crack sooner than a softer bed would.

The slating and tiling standard, BS 5534:2014, recognises this weakness. Under it, a mortar bed is no longer treated as enough to hold ridge and hip tiles down, and a mechanical fixing is expected as well. An older ridge laid on mortar and nothing else therefore rests on a method that today's standard would not accept on its own.

Other causes are simpler. A storm can lift tiles straight off. Movement in an old roof, such as a sagging ridge board, can crack the line of tiles above it. Birds and vegetation work into open joints and widen them. Each of these can leave a ridge looking intact from the ground while the bedding beneath is already failing.

How we repair a leaking ridge

The repair starts with finding where the water is entering. Working from the roof and the loft, we study the tiles, the bedding, the ends of the ridge and the condition of the underlay and timbers beneath. A single loose tile may need only a rebed. A ridge that has cracked along much of its length is usually cleared and relaid rather than patched.

Relaying means lifting each ridge tile, chipping off the old bed and any broken pieces, inspecting the ridge board and underlay, and then setting the tiles again on fresh bedding with mechanical fixings. Where it suits the roof, a dry-fix ridge can replace the mortar bed. The ridge profile follows what the roof already carries, so a clay roof keeps clay ridge tiles and a stone roof keeps a ridge that sits properly with the stone.

If the timber has been wet for some time, the survey report will tell you. Softened wood at the head of the rafters is a smaller job this year than it will be after another winter. For the wider picture of this work, see our ridge and verge repairs page. If you are weighing mortar against dry-fix, the page on ventilated dry ridge explains how that system works, and the answer on dry ridge and the Building Regulations covers the approval question.

MyBuilder's 2026 guide puts a dry ridge at £40 to £60 per linear metre, with a typical installation at £500 to £1,000. Read those as a national yardstick. Our own figure is written down as a fixed price after we have been up and looked.

Sensible steps before the repair day

If you suspect a ridge leak, stay off the roof and look from the ground. The apex is the steepest, most awkward spot to stand on. A pair of binoculars from the ground will often show a tile that has slipped, a gap in the line or a gable end where the bedding has dropped away.

Inside, put a bucket or a tray under any drip and move belongings out of the way. Pulling back the loft insulation around the stain lets the timber dry, though you should not cut into a wet ceiling yourself. Take photographs of the stain and of any debris on the ground, with dates. They help when you describe the problem to us, and they are useful if you later make an insurance claim for storm damage.

A leaking roof gets priority from us, and it is made safe before a larger repair is planned. After a storm, count any ridge pieces on the ground and keep them, because an unbroken tile can often be cleaned and bedded back in its old place. For a closer look at a related fault, the answer on verge clips shows how the gable edges of a roof are held down.