A Comprehensive Guide to Metal Roof Flashing

Water leaks? Water flowing through your chimney walls?

See, there’s more to roofing than just the metal roof itself.

Metal roof flashing provides the additional protection you may not have noticed you needed for your home.

This is your one-stop guide for your metal roof flashing needs…. we tell you ALL the basics and some more insider secrets to get you started.

What Is There to Know About Metal Roof Flashing?

Flashings are your LAST LINE OF DEFENSE from water infiltration.

That said, your flashings should be made of nothing but the BEST MATERIALS there are.

Consider: metal roof flashing.

Metal roof flashings offer the BEST OPTIONS for homeowners.

This is in the same way metal roofing is the most preferred roof for durability and longevity.

You see, metal roof flashing is just one out of many materials used for flashing. Other popular options include PLASTIC and RUBBERIZED ASPHALT.

But unlike plastic and asphalt, metals are able to:

• Withstand harsh weather conditions
• Offer protection from direct sunlight
• Lower down the overall temperature of your home

However, there are a VARIETY of metals and materials you can consider for your metal flashing.

Metal Roof Flashing Materials

These are the metals you can consider for flashing depending on what you need:

Galvanized Steel

Most Popular Option. This metal roof flashing is achieved through the coating of a steel sheet with ZINC ALLOYS.

Pros:

• Economical due to less installation cost
• Aesthetic
• Available in more adjustable lengths

Cons:

• Need paint finishes to improve resistance to rust and corrosion
• Easily affected by pollution, heat, and acidic environment

Stainless Steel

Most Durable. Stainless steel flashings are perfect for counters — tough and corrosive environments.

Pros:

• Good weather resistance
• Not highly affected strong acids like acid rain

Cons:

• Expensive material and installation
• Rigid material

Copper or Lead

Most Reliable. It is an industry secret that copper flashings last your home years more than the other options here.

Pros:

• Longevity
• Weatherproofing properties
• Low maintenance cost

Cons

• Costly material
• Expensive fabrication and installation

Aluminum

Most Versatile. This type can easily be customized because of its VARYING thickness.

Pros:

• Low maintenance and cost
• Highly malleable and customizable

Cons:

• Spoiled in a short time if it is used without painting or anodizing
• Meticulous handling to prevent leakage

Our Verdict?

Choose the materials depending on what you NEED, what you WANT, what you HAVE, and what you DON’T HAVE.

Either way, you can never go wrong with any choice of metal.

Metals already give you the BEST QUALITY for all its given features after all.

So… What Is Flashing?

Flashing is a WEATHERPROOFING METHOD meant to prevent the passage of water into the structure.

You’ll notice that water leaks tend to happen where there is a DISCONTINUITY between surfaces… or simply, in JOINTS.

These joints serve the purpose of connecting surfaces to each other and NOT to prevent leakage.

This is where roof flashings come into play.

You’ll usually find them in places where a hole on the roof is vital for the installation of another feature.

Is it getting hard for you to IMAGINE these holes? Just think:

• Chimneys
• Skylights
• Vents
• Roof valleys
• Eaves
• Rakes
• Ridges

For example, reliable roofing systems have flashings around the BASES OF CHIMNEYS. This is because covering the entire chimney would not allow for it to serve its intended purpose.

The same logic is applied for non-chimney holes on your roofs.

How Does Flashing Keep Water Out of the Roofing System?

There are THREE main reasons:

• Gravity
• Surface tension
• Wind pressure

We can also look at how flashings on roofs can be installed in either of two ways:

• With overlapping panels like shingles, or
• Sealed as one surface

Regardless, we are NOT delving into the science of it all.

Just know that what’s important is that: FLASHING REDIRECTS THE PATH OF THE WATER AWAY FROM THE BUILDINGS OR STRUCTURE.

But if installed incorrectly, flashing CAN direct water INTO the structure instead.

What Are Metal Roof Flashing Types?

Types of flashing are usually named for the LOCATION OF USE or their GENERAL SHAPE.

Let’s familiarize ourselves with some of the DIFFERENT types of metal roof flashing so we can provide our home with the most appropriate type:

Channel Flashing

• Specialized flashings for roofings shaped like a “U”
• Serves to act as a basin for water passing along a ROOF RIDGE where it meets the wall
• Similar to a DRIP EDGE

The concept of KICK-OUT FLASHING may also be relevant for roof ridges and shingles. These are installed at the bottom of a roof and wall intersection to deflect water from the walls.

Valley Flashing

This is self-explanatory: valley flashing protects the VALLEY where two roof planes intersect.

Valleys are vital for a well-designed roofing system. It’s also one of the most efficient ways to help redirect water.

In metal roofing systems, valleys are usually fabricated with HEMS.

Pipe Flashing

You guessed it! This type of flashing is specific for PIPES.

Unlike the seemingly grand structures of general flashings for roofings and shingles, pipe flashing is more concerned with the protection of single pipes.

CHIMNEY FLASHING is a specialized flashing material for… yes, chimneys.

Wall Flashing

Despite its name, wall flashing is still well under the scope of roof flashing types.

These are found at INTERRUPTIONS IN THE WALL: windows, doors, holes, and all points of structural support.

Wall flashing is relevant because it helps prevent water infiltration flow from the roofing and shingles down over to the edge of a window or door openings.

Step Flashing

This is the SIMPLEST type of flashing to install.

This method makes use of OVERLAPS with the pieces of flashing, imagining each other as STEPS.

This feature gives step flashing the name of soaker or base flashing as it emphasizes the dips in between each step.

The innovation of “steps” is important when designing flashings around roofs and shingles that hit walls, chimneys, or any roof elevation.

KICK-OUT FLASHING may also be used here, similar to how COUNTER FLASHING also covers base or step flashing.

How Do We Install Metal Roof Flashings?

After selecting an appropriate flashing material AND type, keep in mind what the flashing will come in contact with.

Some flashing or roof materials can CHEMICALLY REACT and CAUSE STAINS with each other:

• Combinations with copper and lead without any finishes could lead to FASTER CORROSION
• Flashings are more susceptible to EXPANSION AND CONTRACTION without expansion joints

That said, traditional flashing methods are ALWAYS better because of their advantages of longevity and experience.

Here are THREE POPULAR WAYS you can use to install (or make repairs) your metal roof flashings… we refer to them as TRIM:

Rake Trim

Rake trim flashings provide barriers for two-slope roofings with a center peak.

The ends of which need to be cut and angled to fit the roof side while making sure it meets the end wall for an endwall trim.

Rake trims are installed with tapes to SEAL and prevent MOISTURE FORMATION between the trim and the end panel. Likewise, fasteners are also used to set them in place with the roofing material.

Remember to cut them according to your needed measurement.

Eave Trim

An eave trim serves the main purpose of PROTECTING THE ROOF FASCIA.

It’s designed primarily to redirect the water path away from the fascia and directly onto the ground.

A good rule of thumb is to have another layer underneath the placement of the metal pieces. This is to PREVENT MOISTURE rather than leakage.

An advantage with eave trims is the MINIMAL ANGLING required for fitting and needed cut.

Peak Trim

Also known as high side peak trim, these metal roof trim pieces are installed at the HIGH POINT or peak of a roof.

They provide barriers to prevent moisture beneath SLOPING PANELS.

Installing this trim is not at all different:

• It needs to have the appropriate cut, and
• It needs tape to seal and prevent moisture formation within the trim

Now Here’s Our Professional Advice…

HIRE EXPERIENCED METAL ROOFING CONTRACTORS.

You’re already spending SO MUCH on your roofing materials. You do NOT want to waste them just because you install them wrong.

Hire a professional.

It will absolutely make a difference for your homes, buildings, and other related structures.

Final Thoughts

Roof flashings can change the overall quality of your roofing system.

Metal roof flashings offer the best quality to serve this purpose of flashing. You can never go wrong with any of the most trusted metals:

• Galvanized Steel
• Stainless Steel
• Copper or Lead
• Aluminum

Rather, the more tedious part before installing your flashings is the determination of appropriate TYPES and DESIGNS.

Luckily for you, you’ve come across this guide.

Have any more questions? Have you tried out any of the types we’ve discussed? Let us know in the comments section below.