Everything to Know About Step Flashing a Roof

Corners

• Step flashing is installed simultaneously with roofing shingles and is basically interwoven between them. Install the step flashing in the corners first, after shingling up to the sidewall. Bend a piece of step flashing cut at a 45-degree angle flatly against both sides of the wall at the corner. Nail in place using one nail on each side. Caulk the corner using a sealant designed for roofing. Shingles will overlap the end portion of the step flashing on the roof.

Continue the Weave

• As you work around the side wall, bend the step flashing and place it evenly next to the corner piece. Nail it in place. Start overlapping by alternating placement of step flashing and shingles to achieve the weave look. The step flashing piece has shingles above and below it in a proper weave pattern. Continue along the sidewall in this manner until complete.

The Peak

• All the transition areas on the roof require step flashing to channel water away from the house. Step flashing is also installed at the roof peak and held in place with one nail. Caulk around the top of the peak after all the shingles and step flashing have been appropriately installed. As a security measure, apply one last piece of step flashing to the entire peak, molding it to fit; sink one nail to secure it and caulk in place.

Tips & Safety

• It may be necessary to remove small pieces of siding on the side walls if it proves difficult to ease the step flashing under it. When the project is finished, the step flashing should be 50 percent covered by shingles and most of the rest of it should be hidden under the house siding. Wear gloves and work carefully whenever you are on a slanted roof.