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Install step flashing

In the case of an opposing way, you may have to install step flashing to aid in directing water down the roof and over its side.

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Install step flashing by Dan Gutwein on Flickr.With residential roofing, you'll find areas of the roof where two opposing surfaces meet, such as at the valleys between two peaks or when a roof meets a higher sidewall. In the case of an opposing way, you may have to install step flashing to aid in directing water down the roof and over its side.

Step flashing is simply a bent piece of material that sits against the wall and along the rooftop. It can be easily installed by following a few simple steps.

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The step flashing redirects water onto the shingles from the sidewall or the valley where the sidewall and roof meets. With a continuous piece of flashing, a portion of the flashing can become loose from the sidewall, causing the entire piece can fail. This allows water to proceed through the edges of the shingles and possibly into the home itself.

Because the step flashing is in small segments, however, a failure in a single piece can be dealt with by the lower piece of step flashing in the run.

If you need to install step flashing, you can usually do so when dealing with asphalt roofing. The flashing is placed in such a way that it augments the shingle placement, overlapping the shingles so water running down the flashing is carried off the roof without penetration.

To install step flashing, you should:

    • Always begin with a corner piece on the low side of the roof. Cut each piece with tin snips at a 45-degree angle so it can be bent along the corner seam with both the piece of flashing against the wall and the roof lying flat along both surfaces.
    • After fitting the flashing in place, nail it to the wall on both faces of the corner with two nails in each. Flashing should always be nailed to the wall only as the roof can move and anchoring the material to both surfaces can lead to damage.
    • Place a line of sealant along the top of the flashing where you intend to place the next piece. You'll want to make sure each new piece of flashing overlaps the last one placed by two inches.
    • The next step to install step flashing is to bend the next piece of flashing to fit evenly on both the rooftop and the wall. Set one end of the flashing onto the bead of sealant and then nail the top of the other end of the flashing to the wall. Lay the asphalt roof shingle for that row over the flashing and nail it into place.
    • Then overlap the next piece of flashing over the last one placed. You should also overlap the edge of the shingle you just laid as well.
    • Nail the flashing to the wall, and place the corresponding shingle over the flashing for that row.
    • Continue laying the flashing in this way, weaving it with the shingles so the flashing overlaps the lower row of shingles while the upper row of shingles lie over the flashing itself.
    • When you reach the end of the flashing run, place a bead of caulk along the top of all flashing pieces. If the run ends in a peak, then you'll have to cut a flashing piece to fit along both sides of the top of the peak before continuing the run up the other side.

While the process of installing roof flashing is an easy one, it's best to have the work done by a contractor so all materials will be covered by the applicable roofing warranty.

Roofing prices for the step flashing are largely determined by the brand purchased as well as the roofing cost of labor in your area. You can find a local contractor who can install step flashing quickly and efficiently by using Reply!

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Photo credit: Dan Gutwein via Compfight CC.