How to

How to Install Roof Flashing

Flashing is an important component of your roof that protects vulnerable areas from potential water leakage and other forms of weather damage. It keeps the areas around chimneys, vents, and skylights dry and improves the overall longevity of the roof. Unfortunately, it has to be replaced once in a while, but the good news is that roof flashing installation is a simple process.

There will also be plenty of roofing experts in your area who will be willing to help you with the installation if you’re not comfortable doing it yourself. However, if you’re up for a little DIY project, this job shouldn’t be too much of a challenge.

In this guide, we’ll give you a brief run-down of all the different types of materials you’ll need for your roof. Then, we’ll give you explicit step-by-step instructions for getting it securely attached in the right places.

What Kinds of Flashing Do I Need?

A close-up of a metal roofing waterproofing problem area with roof flashings, a complex roof with valleys, a skylight window, snow guards or snow stoppers.

Not all flashing materials are created equal. For every feature of the roof, a different kind of material is needed. Otherwise, it won’t fit properly in its place, and it won’t protect against water damage properly.

Here is a breakdown of the most common types of materials you may need for your roof.


Continuous flashing comes as a long, solid metal unit that can cover large areas. It’s perfect for covering the spot where the roof meets an extended section of siding.


Base flashing is used to go under the bottom of areas where the roof comes into contact with a vertical edge, like around a chimney.


Counter flashing is always paired up with base flashing. It covers the vertical areas above wherever the base flashing has been installed.


Step flashing is very similar to continuous flashing, but it looks like a series of steps descending the roof. It is typically placed wherever the roof connects with a wall.


Kickout flashing is traditionally paired with step flashing, and it acts as a sort of funnel system to help direct rainwater into the roof’s gutters.

Drip Edges

Drip edges are very thin pieces that go along the roof’s edge. They help direct falling water away from the side of the house to prevent water damage.


Valley flashing goes in the shallow part between two elevated areas of the roof. It keeps the part of the roof under the valley protected from leaks.


This is just what it sounds like, flashing designed to keep water from getting into your skylights. Most skylights usually come with their own materials for this purpose.

How Do I Install My Roof Flashing?

A roofer installing flashes around a chimney

The specific process for roof flashing installation is different for each type of material listed above. However, the basics have some considerable overlap, so you should get a solid idea from the following step-by-step instructions.

Step One: Remove Your Shingles

If your shingles are already installed, remove them to make room for the new materials. If not, simply place the underlayment for the shingles underneath where they will eventually go.

Step Two: Install the Kickout

Next, use roofing cement to install the kickout where the wall meets the base of the roof. You will continue to work upwards from here.

Step Three: Attach the First Shingle

Using nails and roofing cement, attach the first shingle over the first strip of step flashing and the kickout you just installed.

Step Four: Place Shingles in a Row

Continue to place your shingles in a row and nail them down until the entire length of the step has been secured to the roof. Keep repeating this process, working upwards until you reach the peak of the roof.

Step Five: Cut Flashing Material At this point, you’ll have to cut your materials with tin snips uniquely to make them fit the roof’s peak. Then, you’ll be done with this simple DIY project.


A dormer on a metal roof.

These instructions for roof flashing installation seem easy enough on paper, but actually doing the job can present challenges for some homeowners. If you’re not comfortable installing yourself, you should get in touch with your local roofing experts for assistance. Either way, you’re sure to end up with a roof that serves you well.