Kerb

A glazed unit installed in a roof to admit daylight, ranging from domed and flat glass units mounted on kerbs on flat roofs to in-plane translucent sheets in profiled metal roofing. Key considerations include thermal performance, fire rating, non-fragility classification and the waterproofing detail at the kerb or laps.

The vertical or near-vertical continuation of the roof waterproofing above the general roof level at abutments, parapets, rooflight kerbs and penetrations. UK guidance calls for upstands of sufficient height above the finished roof surface, terminated with a flashing or capping so water cannot get behind the membrane.

Any element that passes through the roof waterproofing, such as soil vent pipes, flues, cables, plant supports and drainage outlets. Each penetration must be individually sealed, typically with upstands, sleeves, preformed collars or liquid-applied detailing, and penetrations are a leading location for leaks.

A strip of impervious material, traditionally lead but also aluminium, zinc, copper or polymeric products, dressed over joints and junctions such as upstands, abutments and chimneys to shed water over the waterproofing below. Cover flashings are typically let into masonry chases and dressed down over membrane upstands.