What Is Flashing on a Roof?

There’s a reason that roofing experts exist. A lot of knowledge, experience, technique, and technology goes into forming a quality modern roof. You can’t be expected to know it all, and that’s why we all turn to roofing specialists when we need them.

Your friendly expert will tell you a lot about what a roof needs, and in those conversations, you might hear about flashing. Flashing is extremely important for your roof and offers specialized protection for vulnerable elements; but if you know a little more about it, you can better understand why you need it and what options you have when it comes to choosing your flashing.

What Is Flashing?

Flashing is thin sheet metal that is used to direct the flow of water on a roof. It is typically used on pitched roofs, and more often than not, flashing is made from copper, aluminum, stainless steel, or galvanized steel.

It needs to be installed anywhere that shingles join together. This can include chimneys, valleys in a roof, windows, skylights, and a number of other common areas on roofs.

When used correctly, flashing helps to protect the lower levels of the roof from water damage, and it can extend the life of a roof considerably. It also helps to prevent leaks in areas that are more prone to such damage.

How Does It Work?

Waterproof or treated metals are the key to flashing. Because metal is nonporous, it allows water to flow more easily than asphalt shingles. That freedom of flow prevents water from collecting or pooling. The metal also allows water to build up momentum that carries it free of danger spots on the roof that are prone to ponding or leaking.

Ultimately, it’s an additional layer of water protection that utilizes the toughness and longevity of metals to fortify roofing elements.

There are many kinds of flashing, and some of the most common perform specialized functions that help most roofs.

Base Flashing

Base flashing is used where a wall meets with the top of a roof. This is common with second stories, balconies, attic windows, and any other design element that creates a vertical wall structure. If that structure terminates at the top of the roof, it needs flashing.

Base flashing utilizes a single length of metal that is bent to match the roof. It is installed under the siding and shingles but over the underlayment. This makes it hard to see, and because of that, many homeowners and developers opt for less attractive metal materials to save money.

Step Flashing

Step flashing is another way to deal with those same protrusions from the top of a roof. It serves the same ultimate purpose as base flashing, but step flashing is installed above all of the roofing layers. In many cases, it provides better protection, but because this type of flashing is more exposed, it tends to be more expensive.

This mostly boils down to aesthetics. Copper is a more common choice for step flashing because it looks good, but copper is by far the most expensive flashing metal available.

Valley Flashing

When two segments of a pitched roof meet, they often form a valley. Valleys see tons of water runoff and collect debris from the wind. Flashing is important because it prevents these issues from prematurely aging the roof. When wind and water runoff combine, it can create lasting debris and diversions in the runoff that wear down the shingles.

Valley flashing prevents a lot of this by providing a clear, safe path for the water to take. It is installed under the shingles but above the underlayment. The shingles are not overlaid in the traditional way. Instead, the lack of overlay allows the metal to direct runoff and provide a durable extra barrier of protection.

Valley flashing is partially visible, and that can impact metal choices.

Chimney Flashing

Chimney flashing is used at the base of chimneys and vents. These are common elements among houses. The flashing is customized to provide a barrier at every joint between the chimney (or vent) and the roof. The visibility of such flashing varies, so the choice of metal will mostly depend on the design choices made.

There are plenty of other types of flashing that might be appropriate for your roof. What matters is that you have access to roofing experts who can ensure that you have flashing wherever it is needed. In the Dallas region, you can find those experts at Alpine Roofing Construction. Contact us today. We’ll take a look at your roof and discuss what it needs and what options you have to take great care of it.

Contact Us

To top