Roof penetration

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.

A raised frame or upstand constructed on a roof to support and weather items such as rooflights, smoke vents and plant, lifting them above the waterproofing plane. The membrane is dressed up the kerb and the unit itself or a flashing caps the top edge.

A localised element of a roof or below-ground waterproofing system where the continuous field membrane is interrupted or terminated, such as upstands, penetrations, outlets, movement joints and edges. Details demand specific design and careful workmanship, and they are where most waterproofing failures originate.

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.