How To Install Roof Flashing Against A Wall

Even though roof flashing is one of the most important elements of a roof, not many people know how to install roof flashing against a wall properly. Flashing is usually made of sheet metal and is used to seal and protect joints in a building, like those where a roof meets the brick walls of a chimney, from roof leaks by directing the flow of water away from the joint.

4 Steps to Install Roof Flashing

By using the following guidelines for how to install step flashing, you will have a flashing installation that offers the most protection for the home. If you use a roof company in Toronto to install your roof, make sure they install the flashing properly.

1. Install the Underlay Membrane – The underlay membrane you install across the roof deck should be also installed up to the protruding wall a minimum of five inches.
2. Install the First Course of Step Flashing – The metal flashing strips used for step flashing are rectangular and typically 10 inches wide and two inches longer than the exposed area of the roof shingle. For a typical five inch shingle use a 10 inch by seven-inch piece of flashing. Place the first step flashing strip over the end of the starter course shingle and use two nails to fasten the step flashing to the roof with 2 nails. Do not fasten the flashing to the wall because it must “float” with the roof.
3. Apply the First Course of Shingles – Install the first course of shingles up to the wall and position the second flashing strip over the shingle. The covered area of the shingle in the second course should be completely covered by the step flashing.
4. Continue the Process to the Top of the Roof Area – Continue to install the first course of shingles over the step flashing you’ve just installed up to the top of the area you’re working on.

If you liked this post, check out our recent article on how to increase your home’s value.