Does Roof Flashing Need to be Replaced?

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Peter Overton

Accompanied by over 30 years of experience within the external construction sector, my skill set extends to many areas.

If you’re working on a project that requires roof repairs or a complete replacement, you might wonder if the metal flashing also needs to be replaced. In this article, we discuss if and when roof flashing needs to be replaced, as well as explaining how. 

So, does roof flashing need to be replaced? All roof flashing will need to be replaced in time, but it may also need replacing as a result of damage, leaks, or as part of roofing works. 

Read on to learn more about when flashing should be replaced.

Does Roof Metal Flashing Need to be Replaced?

Well-installed metal flashing will typically last a few decades before needing to be replaced, but there are a few situations where it may need to be replaced early. These include:

Roofing Works

In some cases where roofing works are taking place, the flashing may need to be temporarily removed, or replaced for the job to be done correctly and/or efficiently. It may sometimes seem unnecessary to replace flashing before its time, but doing so may benefit the integrity of the roof.


In cases of roof damage, replacing flashing may be necessary in order to prevent leaking and dampness. Even if the damage isn’t strictly focused on the metal flashing, it may still have had an impact on its effectiveness.


If a home is experiencing leaks, metal flashing may need to be replaced to fix the problem. Even if inefficient flashing isn’t the cause of the leak, replacing them may help to prevent future leaks.

Are Roofers Supposed to Replace Metal Flashing?

Roofers may choose to replace old flashing when installing a new roof, or making roof repairs, but sometimes they may simply choose to reinstall existing flashing if it’s in a suitable state. In doing this, roofers can check that the flashing is installed correctly, to ensure its effectiveness, but can also reduce costs for clients. Completely replacing flashing may be unnecessary, and can incur significant additional costs. 

Alternatively, roofers may choose to reinstall some flashing, and replace others as necessary. Good judgement is needed here to ensure the integrity of the metal flashing.

How Long Do Roof Flashings Last?

When installed correctly and looked after, metal flashing on roofs can last up to around 30 years. The lifespan of metal flashing on roofs, however, is determined by various factors:

  • Where you live and environmental conditions
  • Materials used
  • Competency of the builder(s) that installed the roof
  • Damage over time

Can You Reuse Roof Flashing?

Depending on their quality and integrity when removed, roof flashing can be reused, either by reinstalling on the same roof once roof works are complete, or on another job at the approval of the client. When reusing existing flashing, it’s important to first identify any potential issues that may affect its integrity now, and in the future. 

However, regulations do state that flashing should be replaced whenever possible. This is to ensure the effectiveness of the flashing.

How Do You Replace Roof Flashing?

Below you’ll find three guides to installing roof flashings. Bear in mind, however, that this is just a guide and that installation may differ based on the materials used.

Step Flashing

  1. Place the kick-out flashing on the base of the roof, sitting snugly against the wall. Briefly remove the piece and apply roofing cement where it will sit.
  2. Place the first piece of step flashing over the end of the starter strip, ensuring it leads directly into the kick-out flashing. Use roofing cement and two nails to secure it to the roof deck. 
  3. Once the kick flashing and first piece of step flashing are secure, apply a shingle. Apply sealant to the base of the flashing, then lay a shingle on top of the flashing and nail it down as usual.
  4. Repeat to finish the whole course. 


If the property has a chimney, counter-flashing will need to be installed. 

  1. Ensure the chimney’s base flashing has been installed correctly. If there is no base flashing, first install step flashing up the side of the chimney.
  2. Cut an indent into the chimney with a diamond bit saw/diamond grinder disc, and hang the counter-flashing.
  3. Insert the counter-flashing to the indent. Be sure that it hangs so that it overlaps with the base flashing by at least 2 inches.
  4. Use roofing cement to secure the counter-flashing to the base flashing and the chimney.
  5. Seal the indent with roofing caulking, so the counter-flashing hangs securely.

Plumbing Vent Boot Flashing

  1. Install shingles as normal up to the base of the plumbing vent.
  2. Place the flashing or boot onto the plumbing vent, so the base is resting on shingles. Lift the boot and apply sealant to hold the flashing in place.
  3. Firmly push the flashing back down into place.
  4. Install the next course of shingles. When you reach the plumbing vent, allow the shingles to overlap the top of the flashing.
  5. To make room for the vent, cut out a circular piece of the shingles.
  6. To secure the circular edge of the shingle, apply roofing cement beneath it. 

Metal Flashing at Kladworx

Kladworx are providers of aluminium metal flashing to help you decrease water penetration at walls, eaves, windows, doors, and decking. Our metal flashing can be purchased in a variety of sizes, shapes, and colours, as well as bespoke profiles to perfectly fit your project. We also stock aluminium wall copings to further prevent water damage to the property.

Need help with your external construction project?

We are suppliers of some of the most bespoke aluminium and uPVC systems on the market. With over 30 years of experience within the external construction sector, it leaves us well placed to offer our advice on the many different systems on the market

See some of our recent work, or get in touch with us today for a free, no obligation quote.

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