Flashing is a strip of impervious material, usually lead or another metal, used to prevent water penetrating at joints and junctions in a building, such as around chimneys and vents, at abutments where a roof meets a wall, and at changes in roof pitch.
Lead has traditionally been the standard material in the UK because it is durable and easily dressed to shape, although aluminium, zinc and preformed synthetic flashings are also used. Stepped and cover flashings are tucked into the joints of the brickwork and dressed over the roof covering, often in combination with soakers beneath the tiles. For the QS, flashings are normally measured as linear items, stating the material, its thickness or code, and the girth. Poorly detailed or stolen leadwork is a common cause of leaks, so on refurbishment schemes the condition of flashings should be checked rather than assumed.
Related terms: Soaker, Abutment, Leadwork, Weathering.
