Flashing is a part of the system that keeps water from entering through holes created in your roof.  All roofs have penetrations: openings or holes in the roof surface which allow for elements like chimneys, flues, skylights and vents. These necessary holes in the roof, if they’re not properly sealed, can become an entry point for moisture.

‘Flashing’ is the barrier that’s installed around penetrations to keep the roof secure and sealed off from moisture.