ridge tile

A ridge tile is a specialized roofing unit that covers the apex line where two sloping roof planes meet at the top of a pitched roof. It sits astride the ridge, overlapping the upper edges of the roof tiles or slates on both sides, and serves the critical function of weatherproofing the highest and most exposed joint on the roof. Without it, wind-driven rain and snow melt would flow directly into the interior of the building through the gap at the peak.

Ridge tiles are manufactured in two main profiles: barrel or half-round (the curved, semicircular type) and angular or mitered (the sharp-edged type that mirrors the roof plane angle). Barrel ridge tiles are more common in clay and concrete, typically measuring around 330 mm to 500 mm long and 100 mm to 150 mm wide, with a hollow undersurface. Angular types are often used with slate roofs or modern interlocking tiles. The tile must be bedded and mortared in place, either on a bed of mortar or on specialized ridge tile components that allow for thermal movement without cracking.

Installation and failure modes

Ridge tiles are bedded onto a layer of mortar (traditionally lime mortar, increasingly cement mortar) that sits on top of the underlying roof structure. The mortar must be properly compacted and sealed to prevent water ingress at the overlap. Common failures include mortar erosion caused by exposure to wind and rain at the ridge, loss of bond between the tile and its bed, and cracking of the tile itself under temperature cycling or structural movement. These failures are among the most frequent causes of roof leaks because the ridge experiences the greatest wind pressure and exposure to weather.

The term ridge derives from the structural feature itself, the meeting point or ridge formed by the intersection of two roof planes. The tile is simply the cap placed upon it. In slate roofing, ridge tiles are often hand-formed from slate or made from clay to match traditional appearance. In concrete tile roofing, they are cast as integral components of the roof system. Proper ventilation beneath the ridge tile is increasingly important in modern roofing to manage moisture and prevent decay of underlying timber and insulation.