While the pitch of your roof is designed to efficiently and effectively allow water to run off, other protrusions, like chimneys or vents, can cause vulnerabilities in your home that might allow water to seep inside. And if you have a flat roof, these areas can become even more risky.
So, what can you do about it? Flashing is a secure material that offers a waterproof layer to protect your home from the worst weather.
What Is Roof Flashing?
Roof flashing is a type of thin material, often made from metal, rubber, or plastic. It's installed around roof features, like chimneys, skylights, vents, and valleys, to prevent water from seeping underneath the roof tiles and into your home. These intersections are prone to leaks because water tends to gather in the crevices.
It acts as a barrier that directs water away from these vulnerable areas, keeping your home dry and protected from leaks.
Why Is Roof Flashing Important?
You may not think about it often, but roof flashing is critical for preventing some serious issues:
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Stop leaks: Flashing keeps water from seeping into your home through weak spots like chimneys, skylights, and roof valleys.
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Protects your home: It helps preserve your roof and interior, preventing costly water damage and mould.
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Increases roof longevity: Flashing doesn't just keep water out – it also helps your roof last longer by preventing rot, rust, and decay.
Without flashing, water could sneak into your home undetected, causing expensive damage and even health hazards.
What Are the Different Types of Roof Flashing?
Different parts of your roof – and different roof types – require different kinds of flashing to keep water at bay.
Let's break it down:
Apron Flashing
Placed at the base of a chimney or wall, apron flashing is there to direct water away from the structure. It fits securely under shingles, overlapping them to create a smooth flow for water to slide off the roof pitch instead of pooling.
Step Flashing
Step flashing looks a bit like a staircase. It's installed around the chimney or walls and interlocks with shingles to form a protective barrier. Each piece is staggered like steps, guiding water off the roof and away from your home.
Counter Flashing
Counter flashing is placed on top of step flashing to cover the top edges, creating a complete barrier. Water slides down the flashing and away from your roof while keeping the step flashing protected.
Roof Valley Flashing
Roof valleys – the areas where two roof slopes meet – are notorious for channelling water. Roof valley flashing is designed to line these intersections, keeping water from pooling and creating leaks.
What Materials Is Roof Flashing Made From?
Roof flashing comes in a variety of materials, each with its own pros and cons. While metal roof flashing materials are more common, rubber and plastic flashing options are useful for specific applications.
Choosing the right material for your roof flashing depends on factors like budget, location, and roof type.
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Aluminium
Aluminium flashing is lightweight, durable, and highly resistant to corrosion. It's one of the most commonly used materials for roof flashing because of its affordability and ease of installation.
Pros: Lightweight, easy to install, and corrosion-resistant.
Cons: Vulnerable to saltwater and unsuitable for coastal homes.
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Copper
Copper is a premium material known for its durability and unique look. Over time, it develops a distinctive green patina, which some homeowners find attractive – but it can be off-putting for others.
Pros: Durable, highly malleable, and aesthetically appealing.
Cons: Expensive and may develop a green patina over time.
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Stainless or galvanised steel
Metal flashing, like galvanised or stainless steel, are two of the toughest materials used for roof flashing. Stainless steel is naturally resistant to rust, while galvanised steel is coated with zinc for corrosion protection.
Pros: Strong, durable, and cost-effective.
Cons: Galvanised steel can corrode over time if not properly maintained.
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Lead
Lead flashing is known for its flexibility and durability. It's often used when other materials can't provide enough coverage or malleability.
Pros: Exceptionally malleable and long-lasting.
Cons: Expensive and not environmentally friendly.
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Rubber or Plastic
Rubber or plastic flashing is typically used for vent pipes or smaller roof features. It's flexible, affordable, and easy to install, making it a good choice for specific applications.
Pros: Flexible and often used for vent pipe flashing.
Cons: Less durable than metal roof flashings and prone to UV damage.
How To Install Roof Flashing
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Prepare the area: Remove any damaged roofing shingles, tiles, or sheets around the area where the flashing will go. Clean the surface to ensure the best results.
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Install the flashing: Slide the flashing under the shingles and secure it with roofing nails. Make sure it overlaps to create a watertight seal.
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Seal the edges: Apply roofing cement or caulk to the edges of the flashing to ensure there are no gaps where water can slip through.
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Reinstall the shingles: Place the shingles back over the flashing, securing them to make sure everything stays in place.
How To Maintain Roof Flashing
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Regular roof health checks: Look for signs of damage – particularly after storms – like cracks, rust, or gaps in the flashing.
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Clean debris: Keep debris like leaves or moss away from flashing to prevent water from building up.
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Reseal: Over time, the seal around the flashing can wear away. If you notice any gaps, reseal with a roofing cement to keep everything waterproof.
Final Thoughts on Roof Flashings
Flashing ensures your roof remains intact and your home stays dry. Whether you're building a new roof or maintaining an existing one, investing in high-quality flashing will save you money in the long run by preventing costly repairs. There is a range of flashing options for different roofing needs – consider the pros and cons, as well as your own situation, before making your decision.
Roof flashing might not be the most glamorous part of your roof, but it's essential to keeping your home dry and safe – it's one of the best investments you can make for your roof's long-term health.
FAQs
What Does Flashing Mean on a House?
Flashing refers to the waterproof material used around roof features (like your chimney or skylight and any vents) to prevent water from leaking in.
What Is the Flashing Between Two Roofs?
When two roof slopes meet, the area where they intersect is called a valley. Flashing is installed in these valleys to channel water away from the junction, preventing leaks.
What Is the Best Thickness for Flashing?
The thickness of flashing can vary depending on the material used. Generally, a thickness of 0.019 inches for aluminium or 26 gauge for steel is standard, but thicker flashing may be needed in areas prone to harsh weather conditions.