Whether it’s your first DIY project or you’ve tackled a few roofing tasks in the past, roof flashing is a key component to your building’s envelope. Flashing material keeps you warm, safe, and dry by sealing your roof and preventing leaks.
But what exactly is roof flashing? And how does it work? Read on to learn the different types of roof flashing and their uses.
What Is Roof Flashing?
Roof flashing is a thin material that directs water away from vulnerable areas on your roof, particularly where the roof meets walls, chimneys, vents, or skylights. Flashing is used anywhere there’s a joint or an opening.
The main purpose is to prevent water from entering your home, which could cause all sorts of damage – from roof leaks to rotting wood, mould growth, and structural damage.
What Is Roof Flashing Used For?
Flashings are strategically placed around areas of the roof that are most vulnerable. These areas include:
- Roof valleys (i.e., where two roof planes meet)
- Around chimneys, skylights, and vents
- Junctions between the roof and walls
- Along the roof edges
The purpose of roof flashing is to direct water flow away from these vulnerabilities, preventing it from seeping into your home.
Without flashing, water can find its way under the shingles and into your roof deck, which can cause leaks and potentially damage your roof structure. Flashing is essential for a well-built roof.
What Are the Different Roof Flashing Types?
There are different types of roof flashing and roof flashing materials, each with its own uses. Aluminium flashing, copper roof flashing, and steel are the most common materials used.
Valley Flashing
When two sections of your roof meet to form a V-shaped valley, water naturally runs down the slope, making this area prone to water building up, which can cause leaks. Valley flashing runs along these valleys to direct water off the roof and ensure your roof stays watertight.
Base flashing
Base flashing sits around the edges of chimneys or walls where the roof meets vertical surfaces. It prevents water from running down the side of the wall and into the building.
Apron Flashing
Similar to base flashing, apron flashing is used along the base of chimneys, skylights, or any other feature that extends through the roof to create a smooth, watertight seal around these protruding structures.
Counter Flashing
Counter flashing is used with base flashing around chimneys. It’s installed above the base flashing, creating a second layer of protection. The two layers work together to redirect water and prevent it from getting underneath the flashing.
Step Flashing
Step flashing is most commonly used where the roof meets a vertical wall. It consists of short, overlapping pieces of flashing that step up the roof – like a staircase. Each layer overlaps the previous one to direct water off.
Continuous Flashing
Continuous flashing (also called flashing roll or apron flashing) is a single piece of flashing that runs along a continuous section, like the edge of a roof or along a chimney. Unlike step flashing, continuous flashing is a long, unbroken sheet of roof material that acts as a smooth, continuous barrier against water.
Drip Edge Flashing
You should install drip edge flashing along the eaves of the roof, where the shingles overhang the roofline. Drip edge flashing ensures that the water flows off the roof properly without damaging the roof surface or underlying structure.
Skylight Flashing
Skylights are great for letting in natural light, but they can also be vulnerable to water. Skylight flashing is specifically designed to create a waterproof seal around the skylight, preventing any water from entering around the edges of the window, and boosting the longevity and effectiveness of your skylight.
Chimney Flashing
Like skylight flashing, chimneys require specialised flashing as they’re vertical and extend through the roof. Chimney flashing includes a combination of base flashing, step flashing, and counter flashing, creating a robust seal that prevents water from seeping into the joint between the chimney and the roof.
How to Install Flashing?
Installing roof flashing is a tricky job, often left to professionals. Roof flashing must be precisely cut, shaped, and placed to ensure it creates a watertight seal.
However, if you’re feeling up to the challenge, here’s how to install roof flashing yourself.
- Before installing flashing, clean and dry your roof.
- Place the flashing over the joint or area where two surfaces meet. Make sure the roof flashing is properly aligned and overlaps where necessary.
- Use roofing cement or another sealant to seal the edges of the flashing properly.
- Once the roof flashing is installed, test for leaks. Run water over the area and check for signs of moisture.
If you’re unsure about how to go about installing flashing, it’s always a good idea to call in a roofing expert to make sure everything is done correctly.
Final Thoughts on Roof Flashing
Roof flashing is important to keep your roof watertight and your home safe from water damage. It may seem like a small thing, but it plays a huge role in your roof system’s overall performance. Whether you’re installing roof flashing yourself or hiring a professional, understanding the types of roof flashing and how they work can help you make the right decisions for your roof.
FAQs
What Is the Purpose of Flashing on a Roof?
Roof flashing is important in directing water away from vulnerable areas like joints, chimneys, and skylights (or other roof penetration). It prevents water from getting under the shingles and causing leaks or other damage to the structure of the roof.
What Does Flashing Look Like?
Flashing appears as a thin sheet metal or strip, and it can be made of materials like aluminium, copper, or galvanised steel. It’s often shiny, but it can also be coated to blend in with the roof.
What Happens if You Don’t Have Roof Flashing?
Without roof flashing, water can penetrate through vulnerable areas of your roof, leading to leaks, water damage, rotting wood, and structural issues. Flashing is crucial to prevent these problems.
Can You Reuse Old Roof Flashing?
While it might be tempting to reuse old flashing, it’s not recommended. Over time, flashing can become worn, corroded, or damaged. It’s best to replace old flashing with new roof material to keep your roof sealed and waterproof.