What Is Flashing And Why Is It Important?

 Daryl Gentry

 November 17, 2021

Among the various roofing materials used for roofing projects, flashing is often the most overlooked or poorly or improperly installed.

However, flashing is a critical element of the roofing system.

It protects against roof leaks and keeps your roof waterproof and airtight.

Roof flashing seals the outer envelope of your roof that protects the interior of your home from weather and other elements.

In the article below, we will discuss the importance of flashing for the upkeep and protection of your roofing system and your entire home.

What is Roof Flashing?

Flashing is placed around on the areas of your roof’s surface where a projection, like a chimney or a skylight, intersects with the roof.

If these areas aren't sealed properly, it can lead to severe leaks that cause significant water damage.

These intersections should expand and contract depending on temperatures and humidity levels.

The roofing company should install the flashing to allow this movement while creating a tight seal to keep moisture out of the roof and the home.

Roof Flashing Materials

There are several different materials that you can use for flashing.

As long as the material won't degrade from contact with incompatible materials and is impermeable to water, it should work.

Your roofing professional will likely use one of these common materials:

  • Aluminum: Aluminum flashing is easy to form, durable, and relatively inexpensive. It can corrode if it's left in contact with alkaline materials like concrete or fiber-cement siding. It may also degrade from contact with the copper-rich preservatives.
  • Stainless Steel: Stainless steel resists wind damage and denting. It also has superior resistance to metal fatigue.
  • Copper and Lead Coated Copper: These are more expensive and harder to form than aluminum, but they are very durable. Copper is even compatible with newer types of wood preservatives.
  • Lead: Lead is very soft and easy to bend. Lead is very durable and often used for chimney flashing.
  • Galvanized Steel: Galvanized steel is inexpensive, but it isn't as durable as your other options.
  • PVC: PVC is an easy material to work with, and it isn't affected by treated wood, which is great for building a roof deck.

These flashing materials typically come in rolls of different widths that can be cut as needed and bent right at the job site.


Types Of Flashing

Your roof may not have the same needs as your neighbor's roof.

Every roof is different, so the flashing you need will depend on your needs.

Here are a few of the most common types of flashing used in residential projects.

Continuous Flashing

Continuous flashing is applied as a continuous piece across the desired location.

There are some disagreements about the definitive uses of continuous flashing vs. step flashing.

Both are applicable in a few similar situations.

Step flashing is typically seen as the superior option, but continuous flashing still sees its fair share of use throughout the roofing and gutter industry.

Step Flashing

Step flashing mimics a step in a staircase.

It consists of one piece of step flashing that's horizontal and another that's vertical.

They connect to form an L-shape.

A piece of step flashing can be used on corners and edges to prevent water intake.

Despite the debate with continuous flashing, step flashing is just as critical and the appropriate choice more often than not.

Valley Flashing

Valley flashing is used along the borders of two connecting roofing systems, or roof valleys.

This could be the space where the roof above your living room meets the roof above your garage.

This flashing is shaped like an uppercase "W" and will fit snugly over the valley that connects the two roofing systems.

Saddle Flashing

Saddle flashing is typically used for extended joists, beams, or pipes that protrude out of the building envelope.

This is a specific type of flashing that doesn't have a lot of versatility compared to the other options available to you.

Cap Flashing

Cap flashing also forms and L similar to step flashing.

Cap flashing is a common type of flashing used primarily around areas where a building wall or roof meets with a window.

The cap flashing is used to redirect water runoff away from the home.


Why is Flashing Important

The job of your roof is to keep the elements out of your home.

The most common element your roof protects your home and belongings from is water.

Many modern roofs can last between 20-30 years depending on the type of roof, but every roof is subject to some weak points that are prone to leaking.

That’s where high-quality flashing comes in.

The most vulnerable points on any roof are the joints.

A joint is where the slopes on your roof meet.

Unless your home is a perfect rectangle, there's a good chance you have roof valleys where slopes meet.

A dormer is another example of a joint between different slopes in your roof.

Penetration is exactly what it sounds like - anything that requires a hole to be cut in your roof like vents, a chimney, or a skylight.

Water can find its way through your roof and into your home anywhere you have a joint or penetration.

To prevent this from happening, you need proper flashing installed in your valleys and penetrations.

As we said above, flashing is made of materials that are not easily penetrated by water.

It will direct water away from the joints and down into your gutters or off your roof.

If you have no flashing or improper flashing, you will almost certainly develop a leaky roof over time.

Properly installed flashing maintained will provide a barrier against leaks.


Work With A Local Roofing Contractor

If you have more questions about flashing, contact a local roofing professional who can answer all your questions.

TK Roofing and Gutters is committed to providing quality roofing services, including adequate flashing, to their local Ohio communities.

TK Roofing and Gutters has been serving the communities of Northeast Ohio for over 15 years.

Whether you have questions about flashing, need major or minor repairs, or need a complete roof replacement, call TK Roofing and Gutters with any questions you have.

The local roofers at TK Roofing and Gutters can help give you peace of mind and ensure your roofing job is done the right way the first time.Get a Free Quote