Chapter 1: Why do ridge and verge tiles keep working loose on our Herriard house after every gale?
What we find
Altitude is the cause. With the lowest land in the parish 500 ft above ordnance datum, houses here sit above much of the surrounding countryside, and wind arrives with little to slow it. A gust moving up the slope lifts at the roof edge, and the suction at the ridge and the gable end is where it does most damage. On older roofs, the ridge tiles are bedded in sand and cement mortar and the verge is pointed in the same way. After years of frost, that mortar shrinks and cracks, and nothing then holds the tiles except their own weight.
You may find a tile on the lawn after a storm, or notice a ridge line that has gone wavy. In the loft, light along the ridge board or a damp patch on the timbers at the gable are clues.
What we fix
Mortar alone is not enough on a site like this: the tile-fixing standard, BS 5534:2014, calls for mechanical fixing of ridge, hip and verge components. We lift the old ridge, clean off the mortar, and refit using a dry-fix system: a continuous batten, screwed ridge tiles and a vented roll that keeps the roof breathing. Dry verge units clip over the tile ends at the gable and keep the wind out. These systems fall under BS 8612:2018.
Your fixed quote follows the survey, but typical UK reports put a dry ridge on a semi at £900 to £1,600, plus scaffolding at £300 to £900. For the options in full, see our ridge tile repairs page.