Dry ridge and verge systems

Why mortar ridges keep failing

Traditional ridge tiles bedded on mortar rely on that bed staying intact through frost, movement and wind uplift. On an exposed roof it often does not. Once a ridge tile slides or the bed shrinks, water and wind get into the head of the pitch. Re-bedding can be the right repair when the rest of the roof is sound and the exposure is modest. On a roof that has already lost its ridge more than once, a dry system is usually the more honest fix.

How a dry ridge works

A dry ridge uses a ridge roll or union, mechanically fixed ridge tiles and a ventilated or closed detail as specified. It does not depend on a mortar bed for its strength. It also gives a chance to look at the head of the rafters and the underlay while the old ridge is off — something that should be done, not skipped.

Verges

The gable verge takes a similar beating. Mortar-bedded or poorly boarded verges can lift, crack or let water into the gable wall. Dry verge systems cap and fix that edge in a way that is tidier and typically more resistant to wind. They have to suit the tile or slate profile; this is not a one-size extrusion for every roof.

Part of a wider look

If the covering below the ridge is already at the end of its life, fixing only the ridge will not transform the roof. We will say when a dry ridge is a smart, self-contained upgrade and when it should sit inside a larger re-roof.