Ing Step Flashing For Shingles Code Looks At

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Changes are submitted and approved and can then be reviewed in subsequent cycles.

Ing Step Flashing For Shingles Code Looks At

Controversial changes get people and the building industry thinking, which is what happened recently with the way code looks at sidewall flashing in asphalt-shingle installations.

With this method, L-shaped pieces of metal that are a couple of inches longer than the shingle overlap are installed on top of each shingle adjacent to the sidewall, and the flashing is then laced into each course.

Step flashing ensures that any water that migrates underneath a shingle will still end up on top of the flashing that is covering the shingle below.

And in section 905which covers the installation of all roof coveringsof the 2015 IRC, the first sentence requires compliance with the code and the manufacturers installation instructions.

Continuous flashing has always been used at a headwall (an intersecting wall at the top of a roof plane and perpendicular to the slope).

In this case, continuous flashing is simply a single piece of flashing placed behind the exterior cladding and weather-resistive barrier on the wall and then extended out over the shingles.

The flashing can be left exposed, or installers can adhere a beauty strip of asphalt-shingle material to the flashing to make it less visible from the ground.

After decades of sidewall step flashing being installed beneath the shingles, continuous flashing is most likely to be installed below the shingles as well.

But some installers may assume that continuous flashing should be installed above the shingles, as is done for headwall flashing.

In those applications, the continuous flashing installs under the roofing.

The small roll along the long edge of the continuous flashing helps to ensure that water will flow down to the bottom of the flashing and not migrate sideways and off the flashing.

Asphalt shingles, however, are not rigid like clay or slate, and a J-roll would likely telegraph a hump to the finished surface.

Additionally, asphalt shingles would not protect the J-roll from getting flattened by someone walking on the roof.

But the IRC does not mention a J-roll along the edge of continuous flashing in an asphalt-shingle application.

Mike Guertin touches on continuous flashing in his roofing demos for JLC Live, and his insights for installing continuous flashing are provided in Installing Continuous Flashing.

But because this new subject is not clearly spelled out in the code, I would encourage you to do a little homework before trying to change the decades-long practice of using step flashing with asphalt shingles.

Review the installation instructions of the product you are installing and perhaps contact a technical representative at the manufacturer for guidance for an alternative installation method that uses continuous flashing.

But perhaps the easiest solution is to leave well enough alone and continue using the tried-and-true step-flashing method.

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Installing Step Flashing For Shingles