All You Need To Know About Roof Flashing

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If the interiors of your house have been one of your most prized possessions, a leaking roof is definitely a threat to it all. That is why homemakers invest in proper roof flashing. It is one of the most important things you must do to ensure that your whole house is safe and sturdy.

What Is Flashing on A Roof?

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Your roof is the main shield of your house. That is why installing protection is important. Before you start working on your roof, you should know what is flashing on a roof. Well, it refers to the material that pushes the water away from important areas on your roof. You need well-fixed roof flashing on the part of your roof where the plane side meets the vertical side. This is generally around the wall and the dormer. Flashing is required to surround important fixtures on your roof like chimney, vents and skylights.

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Without it, the rainwater will find its way inside your house through the crevice between your wall and the roof. This will spoil all the interiors of your house and cause massive inconvenience. With proper roof flashing, the water simply runs down from the sides and goes through the shingles.
Improper flashing, especially around the chimneys, is the main cause of roof leaks. If ignored, leaking roofs will not just spoil your interiors but will also cause wood rot and deck collapse. This is why you need to act on a leaking roof promptly and install proper flashing on the roof.

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What Are the Important Roof Flashing Types?

If you are considering protecting your roof against water, you should know about all the common roof flashing types so you can choose the best one for your roof. You must consider all the fixtures on your roof and the overall built of your house while installing your flashing. Here are the important types:

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  • Continuous Flashing: Also known as “apron flashing”, continuous flashing is a long, single piece of metal that will drive the water down to the shingles. Since roofs contracts and expands according to the changing levels of heat in the weather, these long pieces of metal come with built-in expansion joints to adapt to the size and stay intact.
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  • Base flashing: To ensure that the water definitely falls on the flashing, some fixtures on your roof like the vent or the chimney require additional pieces of flashing. Installing flashing around these fixtures can be tough. That is why base flashing is considered around these fixtures. Even when the roof contracts and expands with the heat levels, the additional piece of metal ensures that the whole structure is sturdy. Base flashing is the piece below the main flashing.
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  • Step flashing: Step flashing is done on the area between your wall and the roof. It is a metal cut rectangularly and bent to 90-degrees at the centre. Step flashing saves your house from hidden damages that cause slow erosion.
  • Drip Edge Flashing: Eaves or the edges of your roof require proper, drip edge flashing. Without this, the water from the gutter will get accumulated on the edge of the roof and underneath the shingles. On a day when it is raining sideways, the water can circle up in the last shingle and make its way into your house. Drip edge flashing is bent on an L-shape. Without it, the wood board will catch mold, the drywall will get ruined and the chances of roof deck getting crumbled is higher.
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  • Valley Flashing: It is common for shingles to erode from the valley of your roof. Valleys are the angled dip joints where the two sides of your roof meet. Valley flashing comes in V or W shape and stretches all the way down to the drip edge. It is important to make sure that it overlaps the drip edge flashing. It should be tightly attached to the seams and cemented properly in order to avoid roof leaks.
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  • Vent Pipe Flashing: While vents allow a proper flow of air, they also allow the rainwater to creep inside your house. That is why a special type of flashing is recommended for your vent pipe. This cylindrical fashing is attached This is a snugly over pipes on your roof. They are cylindrical from the top and flat on the bottom and one of the most important flashings for the roof.

What Are the Different Roof Flashing Materials?

Older homes often have roof flashing made of lead. It was used for its strength and durability. However, roofing professionals today prefer more lightweight and sustainable materials for their metal flashing. Here are the preferred metals for roof flashing today:

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  • Aluminium: Aluminium flashing is preferred by professionals because it is lightweight and moulds easily around the edges and fixtures of your roof. However, it must be coated properly with cement and masonry to avoid corrosion.
  • Steel: Steel is comparatively more corrosion resistant than aluminium. It is also comparatively more malleable. Professionals often mix and match aluminium and steel flashing depending on the area and design of the roof.
  • Copper: Copper can be easily soldered and has high value due to its durability. It is usually preferred for flashing around chimneys.

What Are Things You Should Have Before Roof Flashing Installation?

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Taking professional help for roof flashing is recommended as it is an important step towards safeguarding your house from leaks and erosion. Moreover, professionals are often well equipped with the tools and knowledge to required for roof flashing installation. Here are the tools that you need:

  • The main roof flashing
  • Nails and hammers
  • Tin snips
  • Cement and masonry
  • Leather gloves


  1. Is Roof Flashing Necessary?

    Absolutely! Without roof flashing, your house stands vulnerable to the rain. It will eventually make the roof fall off and cause serious damage.

  2. Does Flashing Rest Above or Below the Shingles?

    It is defective when the flashing is installed between or below the shingles. Flashing should rest above the shingles. According to the National Roofing Contractors Association, step flashing must be 14 inches above the shingles.

  3. How Often Should Roof Flashing Be Replaced?

    It is important to consider roof flashing replacement after every 15 to 20 years.

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