What is Roof Flashing?

If you have ever required roof repairs in London, you’d have likely heard the term “flashing”. But just what does this mean?

Flashing is part of the waterproofing system of your rooftop. It is usually made from either metal or a rubber membrane and is the barrier that roofers install around penetrations in the roof to keep it secure and sealed from moisture.

All rooftops have penetrations, including flues, chimneys, skylights, and vents. There are also areas prone to leaks including valleys and intersections between dormer walls and the roof surface. Flashing prevents long-term water damage to the framing and siding or your home. Without flashing, rainwater and snowmelt will have easy access to your attic space and eventually wreak havoc on your home.

Flashing is usually composed of materials like aluminum, copper, stainless steel, galvanized steel, lead, zinc-alloy, or lead-coated copper. It can also be made of PVC plastic sheeting, rubber, or bituminous (tar-like) fabric.

How is Flashing Installed?

Flashing is installed after the roof frame and the waterproof membrane of the roof are installed. Flashing is nailed in place around any penetrations in the rooftop, and the gaps between the flashing and the penetrations, and between the flashing and the waterproof membrane, are sealed with caulk or waterproof cement.  Roof cladding will then be installed.

  • Chimney Flashing is installed at the base of the chimney along the base and up the sides.
  • Skylight flashing is often integrated into the skylight.
  • Continuous flashing will protect the joint between a sloped roof and a vertical wall.
  • Drip edge flashing prevents seepage of water under the roof along rake edges and eaves.
  • Valley flashing protects channels where two planes of a rooftop meet.
  • Step flashing provides protection where a rooftop meets side walls of any kind.
  • Vent Pipe flashing is conical in shape to fit over pipes and flues.

It’s important that care is taken so that metal flashing doesn’t contact metal roofing materials, as this can result in galvanic corrosion down the track.

For all roof repairs in London, Ontario, including replacement of flashing, call Roofing Ontario for the very best in professionalism, service and competitive pricing. You’ll be delighted with the results!

Contact us today to learn more about your roofing options.