Flashing works

The importance of flashing is often dismissed, but it is an essential element for a building to remain waterproof. Flashing is a construction detail used to seal and protect joints in a building from water penetration – it is therefore installed at intersecting roofs, parapets and walls.

The joints created by the intersection of the roof and roof mounted structures and projections, such as parapets, hatches, skylights, chimneys, vent stacks, or towers, are among the most vulnerable areas of roofing systems. They constantly expand and contract in response to changes in humidity and temperature. The greater the number of such projections, the greater the potential for serious leaks. Flashing is used at these intersections to keep rainwater from leaking into the building. It makes joints at these junctions watertight, while at the same time allowing the natural expansion and contraction of materials to continue.

Flashing can either be concealed or exposed. Flashing concealed within the construction of the building may be of either sheet metal or a waterproof membrane. Exposed flashing typically consists of pieces of sheet metal or impervious, flexible membrane material. We often find that the flashing may have failed and this is the cause for water penetration.