The short answer
On open ground the wind reaches the ridge and the gable edges first. A ridge or verge that is bedded in mortar alone can loosen over the years and let tiles lift. A ridge bedded in mortar alone is below today's standard, which asks for mechanical fixings as well; a tested dry-fix system is the other route.
Burbage lies on a watershed at the east end of the Vale of Pewsey, and a roof on the village edge gets little shelter from the land around it. The ridge, the high line where the two slopes meet, and the verges, the edges on the gable ends, are the parts that take the most wind, along with any porch or garage roof standing clear of its neighbours.
Q3.1How do ridges fail?
Traditional ridge tiles were bedded in mortar. Mortar cracks as the roof moves, then loosens, and eventually a tile lifts. A loose ridge tile is a danger below as well as a leak above, so it is worth acting early, and we would always rather refix one tile than replace twenty after a gale. If you can see cracked mortar from the ground, a closer look is overdue.
Q3.2Mortar, clips or dry-fix?
The 2014 revision of BS 5534 ended reliance on bedding mortar alone for ridge and hip tiles, so clips or screws are added to the bedding. Dry-fix systems, tested to BS 8612, hold the ridge with clips and screws and a ventilated strip instead of a mortar bed. Both approaches work. We choose between them based on the roof, its tile type and how exposed the house is.
Q3.3What about the verges?
Verge tiles on a gable need to be fixed and sealed against the wall below. A cracked mortar verge, gaps at the barge board or lifting end tiles are signs of an edge that needs work. Our ridge, verge and dry-fix page shows what is involved, and the survey photographs make it clear which method is suitable. Whichever we choose, the verge and ridge are left clean and sealed, and any broken tile is cleared from the site.