When homeowners think about their roof, they often focus on shingles and overlook the materials that help keep the entire system watertight. One of the most important components is roof flashing. Roof flashing is a thin, corrosion-resistant metal material shaped to fit roof joints and vulnerable areas where water could penetrate. On shingle roofs, it is typically installed between the underlayment and shingles, while on metal roofs it is commonly installed over the panels.
The purpose of roof flashing is to direct water away from critical areas of the roof and help prevent leaks, mold, mildew, rot, and even pest infestations.
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What Is Roof Flashing?
Flashing is a thin layer of waterproof material. It is designed with one main purpose in mind, which is to keep water from getting into places it does not belong. Flashing is meant to carry the water over certain crevices so it does not get into unwanted areas. The most vulnerable areas of your roof are where the roof’s surface ends or is met by a different surface, such as:
- Dormers
- Chimneys
- Vertical walls
- Parapets
- Cupolas
- Vents
- Skylights
- Roof edges
- Roof valleys
Why is Proper Flashing Installation Important?
Proper flashing installation is critical to preventing roof leaks and protecting vulnerable areas of the roof from water intrusion. Flashing must be installed correctly so water flows away from seams and penetrations rather than underneath the roofing system.
It’s also important not to rely on caulk as a replacement for flashing. While caulk may temporarily seal small gaps, it can crack and deteriorate over time, leaving the roof exposed to leaks and moisture damage.
Improperly installed flashing can lead to mold, rot, interior water damage, and costly repairs. That’s why homeowners should choose a roofing contractor with experienced crews who understand the importance of proper flashing installation.
Different Types of Roof Flashing
Roof flashing comes in several types to suit different needs. Step flashing and continuous flashing are most often used around protrusions from the roof like chimneys and dormers, for example.
1. Apron or Continuous Flashing
Shaped like an L, apron flashing is used at the base of a wall or penetration. It can be up to 14 feet long to fit the base of the penetration.
2. Step Flashing
Step flashing is mainly used against the sides of walls and chimneys. A piece of metal flashing is placed under every shingle installed against the side of a wall to stop water from running down into it. As indicated by its name, step flashing is installed as each shingle is installed.
3. Base and Counter Flashing
Similar to step flashing, counter flashing is used on walls and chimneys. But counter flashing is sawed into an existing mortar joint. Unlike counter flashing, the metal comes up over the top of the brick.
Base and counter flashing are used together to protect leak-prone roof protrusions like chimneys. The base flashing is a continuous L-shaped piece that attaches to the roof, but its upper edge is not attached to the roof penetration. The counter flashing piece is attached to the penetration but not to the roof, so the pieces of flashing overlap but are not secured to each other. This system of base and counter flashing allows for expansion and contraction without damage, which is especially important in areas that are difficult to waterproof, like chimneys.
Roof flashing that you can see is usually considered counter flashing.
4. Drip Edge Flashing
Flashing is installed at the edge of the roof to stop water from running down the fascia boards and into the soffits. The simplest type of flashing is an L-shape, but there is also T-shaped and F-shaped drip edge flashing.
5. Valley Flashing
Roof valleys are prone to leaks because of the amount of water that flows through them. Roof valley flashing creates a V-shaped channel for water that runs into the areas where two roof slopes meet. Valley flashing can be hidden under shingles or left exposed in open valleys. Open valleys happen with certain roofing materials that cannot bend to “close” the valley.
Valley flashing can be one piece of continuous flashing or several overlapping pieces, like step flashing.
6. Pipe Flashing
Pipe flashing looks like a one-piece collar that fits around the diameter of a pipe. Unlike other roof flashing types, it can be made of rubber or silicone instead of metal for easier expansion and contraction.
7. Wall Flashing
The area where the roof meets an exterior wall is usually lined or covered with wall flashing for extra waterproofing.
What Are Flashing Materials Made Of?
Roof flashing can be made from several different materials, each offering unique benefits depending on the roof type, budget, and desired appearance.
- Aluminum: One of the most common flashing materials because it is affordable, lightweight, easy to install, and available in a variety of colors to match roofing and siding.
- Lead-Coated Copper: A durable, long-used flashing material known for its smooth gray appearance and added corrosion resistance.
- Copper: A premium flashing option valued for its durability, flexibility, and attractive appearance. Over time, copper develops a natural patina, though it is typically more expensive than other materials.
- Galvanized Steel: A cost-effective and functional flashing material commonly used in roofing systems, though it can become discolored over time.
Do You Have To Replace Your Roof Flashing When You Replace Your Roof?
If you’re getting a roof replacement, you should have the roof flashing replaced as well. Old flashing will not last the lifespan of your new roof, and it’s better to have it replaced now rather than later when it starts to fail and cause water damage.
If you have a newer roof and you’re getting a repair, you may be able to keep your existing flashing. To reuse flashing, your roofer will need to remove it carefully to avoid damaging it and then inspect it.
Some types of flashing, like step flashing, are difficult to reuse because it’s likely to be dented or damaged when separating from the old shingles.
New flashing should not be layered on top of the old flashing. You should only have one layer of flashing on a roof at a time.
What Else Is There On a Roof Besides Flashing?
The first layer of a roof is the decking, the wooden boards that create the framing of your roof. The next layer is the underlayment, a felt or synthetic material that helps protect the decking from water damage. Before shingles are laid, a drip edge—a type of metal flashing—must be installed to prevent water from flowing into your roofing components.
Ice and water shields (waterproof barrier) should also be installed at roof valleys and near penetrations like chimneys.
At roof peaks where two slopes of the roof meet, ridge capping should be installed. Ridge capping is thicker than regular shingles and pre-bent so it can form to the ridges on your roof.
Contact Northpoint Roofing for Roof Flashing Inspection & Repair Services
When it comes to protecting your home or business, choosing the right roofing contractor matters. At Northpoint Roofing Systems, we provide expert residential and commercial roofing services throughout Tennessee and Georgia, specializing in roof repairs, full replacements, storm damage restoration, and detailed inspections for all roofing types, including shingle, metal, and tile roofing.
Our team believes in doing the job the right way without cutting corners. From comprehensive inspections and leak repairs to properly reflashing every roof we install, our skilled crews focus on quality craftsmanship and long-term protection. Whether you’re dealing with storm damage, a leaking roof, or it’s simply time for a replacement, Northpoint Roofing Systems is ready to help with trusted service and expert solutions every step of the way.
Contact us today to schedule your free roof assessment, and let our team help restore confidence in your roof.
