The short answer
Roofs on high, open ground are worth fixing a little more securely at the edges. Ridges, hips and verges take the wind first, so tiles there should be clipped or screwed, not just bedded. That is the modern standard anyway, and it makes a hilltop roof more forgiving in a gale.
Kington Langley stands on a hill that rises to about 100 metres towards its western end. A roof in that setting is not unusual, but it does get the wind from more directions than a roof tucked in a valley. When we survey a house here, the edges of the roof get most of our attention.
Q1.1Why are verges and gable ends the first casualties?
A verge is the finished edge of a roof above a gable wall. Gusts push upwards under it, so a loose verge tile is among the first casualties of a storm. The end of each course should be held against the wall with a mechanical fixing, either screws and clips or a dry-fix verge system. If the verge has only ever been mortared on, it may be due a refix.
Q1.2How should ridge and hip tiles be fixed?
Since BS 5534 was revised in 2014, bedding on mortar alone has not been treated as enough for these tiles. Each ridge or hip tile should have its own mechanical fix, and the ridge run should hold even if the mortar crumbles. Dry-fix systems, tested to BS 8612, do this without wet mortar and are often the neatest answer for an exposed ridge.
Q1.3Do the tiles and underlay need extra care?
Individual tiles on an exposed slope may need clipping, particularly the first rows near edges. The underlay beneath, which is the sheet that catches whatever gets past the tiles, has to be sound and properly lapped, or it flaps and wears through. Our ridge, verge and dry-fix page explains the options.
None of this means a hilltop roof is fragile. It means the details should be fitted as the standard intends, and checked from time to time, ideally after a hard winter and before the next one. A quick look from the ground with binoculars, or a photograph taken by a surveyor, shows a slipped verge tile long before it comes down.