Roof ridges, hips, valleys and flashing details
How the most exposed pitched-roof junctions shed water and resist wind.
This is general information, not a survey, design, legal or Building Control decision. The correct scope and standard depend on the property, work, date and regulatory route.
Ridges and hips may use mortar bedding, mechanically fixed systems or dry-fix components; valleys may be tiled, lead-lined or formed with an approved proprietary tray. The correct detail depends on the roof covering, pitch, exposure and supporting construction.
Leadwork needs appropriate laps, welted or chased details where specified, clips or fixings that allow movement, and separation from incompatible materials. Alternatives such as proprietary GRP, aluminium or polymer systems are not interchangeable by marketing description: use the covering manufacturer's approved detail.
Inspect junctions for lifted caps, cracked mortar, corrosion, splits, shrinkage, debris and staining inside the roof. Do not seal over a drainage path or rely on mastic as a substitute for a correctly designed flashing.