Ridge tiles are located at the highest and most exposed point of any pitched roof. The mortar bed that holds them in place weathers faster than almost any other connection to the building, and when it fails, the consequences range from water ingress to loose roof tiles falling from a height. This article explains what to look out for, why it matters, and when to call a roofer.
What are ridge tiles and why are they important?
Ridge tiles are the specially shaped tiles that cover the top of a pitched roof where the two roof slopes meet. They are laid in mortar and can also be finished with a finishing layer over the joints between the tiles.
Their goal is threefold:
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Sealing the ridge line against water intrusion — the top is one of the points on the roof most exposed to rain.
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Prevent wind from blowing under the top rows of the main roof tiles.
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Cover the roof structure and protect the wooden ridge beam underneath.
When ridge tiles fail — whether due to mortar deterioration, cracking, or shifting — all three functions are compromised simultaneously.
Signs of bad or failing ridge tiles
1. Crumbling or missing mortar between ridge tiles
This is the most common sign. Lime or cement mortar between ridge tiles cracks and crumbles due to years of thermal cycles — expanding in the heat, contracting in the cold, and absorbing and repelling moisture with every rain shower. You may notice:
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Pieces of grey or white mortar in the gutters.
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Visible gaps between ridge tiles when looking along the ridge line from the ground.
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Mortar that appears powdery or detached when viewed with binoculars.
2. Ridge tiles that wobble or move under pressure
If you (or a roofer) press on a ridge tile and it moves, shifts, or wobbles, it is no longer adequately set in the mortar. It is held in place by nothing more than friction and the compression of adjacent tiles. Strong winds or expansion caused by the freezing of residual moisture in the joint can completely dislodge the tile.
3. Visibly tilted or crooked ridge tiles
Looking along the ridge line from the edge of the roof, individual tiles that are leaning or positioned at a different angle than their neighbors have left their original position. Even a few degrees of tilt compromises the watertightness of the joint.
4. Cracks in ridge tiles
Ridge tiles crack due to frost action, thermal stress, and physical impact. A cracked tile cannot be effectively repointed — the crack will reopen during the next temperature cycle. Cracked tiles must be replaced.
5. Damp patches in the house near the ridge line
Leakage through the ridge often does not appear directly underneath — water travels along the ridge beam and rafters before finding its way to the ceiling. A damp spot near the middle of an upper-floor ceiling, or in the attic near the ridge, is a strong indicator of ridge tile failure.
6. Ridge mortar applied over old mortar
A commonly used, low-quality repair method is to apply new mortar directly over the old without removing the failed bed. This results in a repair that initially appears adequate but fails within two to three years because the adhesion is to the failed material rather than the surface of the tile.
7. Corner ridges showing the same deterioration
Where a roof has hip rafter sections — the angled corner joints — hip ridge tiles are laid in mortar in exactly the same way as ridge tiles and deteriorate at the same rate. They require the same inspection attention.
Why loose ridge tiles are a safety risk
A ridge tile that has completely lost its mortar bed can be dislodged by wind speeds well below gale force. At the height of a typical two-story house — 7 to 9 meters — a shifted ridge tile poses a serious risk due to falling objects. Ridge tiles weigh between 3 and 8 kg, depending on the type. Therefore, we treat urgent calls regarding ridge tiles as a priority — we aim to visit the same day once it is confirmed that tiles are loose.
How to correctly repair ridge tiles
The correct repair process:
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All ridge tiles in the relevant section are carefully removed.
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All old mortar is completely scraped away — not smeared over it.
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Pan and seat surfaces are cleaned.
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A fresh mortar bed of the correct specification is laid.
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Ridge tiles are put back and pressed into the bed.
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All joints are finished with a flexible joint sealant that resists future cracking.
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The repair is inspected from both the roof and ground level prior to completion.
This process, if executed correctly, should last 20 to 30 years before further attention is needed.
Can you check ridge tiles yourself?
From the ground with binoculars, you can assess:
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Whether the ridge line is straight or whether tiles are visibly tilted or crooked.
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Whether mortar is present or visibly missing mortar in the joints.
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Whether roof tiles appear cracked or shifted.
This is a useful initial check, but a definitive assessment of whether tiles are still firmly in place must be carried out by a roofer on the roof — by pressing down each tile individually.
