Types of ridge tile

1Half-round ridge, the familiar curve

The half-round ridge is the shape many people picture: a smooth arch that sits across the top of the roof like a rounded cap. It is simple to make and simple to lay, and it suits a wide range of tiles and slates.

Half-round tiles are laid end to end and bedded along the ridge, with the joints lapping or butting depending on the pattern. The curve sheds water in every direction and looks tidy against the sky.

Because it is so familiar, it is also the profile people assume they have when they do not. Measure the width and check whether the ends are plain or have a socket before ordering a replacement. A tile that looks the same from the ground can turn out to be a different size, and a poor fit leaves gaps for water.

Plain half-round sections are also the usual choice on dry ridge systems, where the tile clips over a batten and the joint is covered by an end or closer piece.

2Angled ridge, the two-faced peak

An angled ridge has two flat faces that meet in a point at the top, like an upturned V. It gives a sharper, more modern line than the curved type, and it is common on newer concrete tile roofs, where the ridge is designed to match the flat or ribbed tile profile.

The angle itself varies. A ridge intended for a steeper roof does not sit well on a shallow one, and the underside has to follow the pitch of the slopes. A mismatch leaves gaps that mortar then has to fill, and mortar is a poor substitute for the right shape.

When ordering, give the pitch of the roof as well as the profile, because an angled tile is made for a range of slopes and not every one fits every roof.

Angled tiles may be fixed with mortar, with clips or on a dry ridge system. Our page on whether a ridge can leak explains how the joints and underlay work together beneath them.

3Ornamental and crested ridges

Ornamental ridges carry a decorative top, such as a scalloped crest, a row of points or a raised roll. They belong to the Victorian and Edwardian houses that sit near the seafront in towns like Worthing, where a decorative ridge was part of the building's character.

These tiles are harder to match because many original patterns are no longer made. Clay crested ridges also weather unevenly, and the crests are fragile, so a broken one can be difficult to replace without taking down a stretch of the run. Finials, the raised pieces that cap the end of a run, can be the first to work loose.

Where a house has listed status or lies within a conservation area, the existing ridge may matter to the look of the street. The foot of a hip on these houses is often a crested run too, and it needs a support of its own.

4Clay and concrete: how they differ

Clay ridge tiles are fired and tend to keep their colour through the body of the tile. Marley quotes a minimum life expectancy of 60 years for clay tiles, a figure determined by the Building Research Establishment. Concrete is cast, takes its colour from the surface or the mix, and Marley describes concrete tiles as expected to last for around 60 years, with the caveat that this is not a guarantee.

Concrete ridges are heavier and their surface can wear and fade over time, while clay tends to age more gently. Both can crack, and both rely on a sound bed or clip system to stay in place.

These lifespans are typical figures and depend on exposure, workmanship and maintenance. When a ridge is replaced, the new tile should be the same material as its neighbours, as clay and concrete weather differently and sit differently on the bed.

5Choosing and fixing the right one

When we survey a ridge we note the profile, the material, the colour and any maker's marks, then match them to a tile that sits properly on the run. A good match looks right from the street and seals the joints.

Fixing is the other half. Since the 2014 revision of BS 5534, a mechanical fixing goes in beside any mortar, so whichever type you have, the fixing method is chosen for the exposure of the site. A note of the profile and size, kept with your house papers, means any future repair starts from facts.

Gusts hit hard on this coast, which is why our page on ridge tiles in coastal wind is worth reading before you commission work. For the side of the roof at a gable, see what a verge undercloak is. The full list of jobs is under ridge tile repairs.