How Much Does it Cost to Repair Chimney Flashing?

A chimney has many different components, all of which play an important role in how well it performs.

Your home's safety is jeopardised if a portion of your chimney is broken, completely broken, or simply missing. The flashing of a chimney is no exception.

People frequently discuss tuckpointing, sweeping, liners, and other chimney services, but flashing frequently goes unnoticed. However, chimney flashing is a critical component of your chimney's functionality.

In this guide, we will go over how long it takes to repair chimney flashing, the different types, and the cost to remove chimney flashing. So, if you need your chimney flashing repaired, you will find everything you need to know here!

chimney

If you have moved into your new home or haven't worked on your existing chimney in a long time, you should look for signs of flawed chimney flashing. Chimney flashing is the main cause of chimney leaks and, therefore, can lead to major problems if not addressed immediately.

Failure of chimney flashing can cause damage to your roof and attic. You should not take roof damage lightly, so if you start noticing any damage, you should contact a roofing company right away to have it repaired. Not to mention that poor flashing can cause significant water damage to your actual chimney.

If enough water rushes into your chimney, the mortar and brick joints will become brittle, threatening the structural integrity of the entire structure.

You should have your chimney inspected at least once a year to prevent this from happening. It is always best to be safe than sorry. Repairing minor flashing damage is preferable to having to replace your roof and chimney due to water damage.

The lead flashing around a chimney protects the overall roof structure from the elements by keeping the rain out of the vulnerable area of the roof where the chimney meets the tiles.

Good lead flashing should last decades, but if it is not properly installed or is too thin, it can break easily or crack, causing larger problems.

The cost to replace all four aspects of flashing (the apron, step flashing, and back box) is about £400 to £500 for materials and labour - but this is the cost if no scaffolding is used.

If it is required, as it is frequently with chimney jobs, particularly on two-story homes, the cost will be around £300 to £400 higher, implying that a typical cost to replace lead flashing on a chimney is around £800.

If you are purely trying to fix the flashing with a new section or welding up cracks, the repairs themselves can cost around £200, but the cost of scaffolding will increase this.

A well-installed chimney or roof flashing could last up to 30 years. Lifespan is determined by environmental factors such as where you live, the size and shape of your chimney, and the materials used to construct it.

Knowing the year your house was built can help you keep track of how long your chimney will last.

The following are indications that it's time to repair your chimney flashing:

  • Leaking from the chimney's interior or exterior
  • Dripping sounds and evidence, such as puddles
  • Bricks that are discoloured
  • Stains caused by rust
  • Interior water stains on the ceilings or walls adjacent to the chimney
  • Gaps in the sealant around the flashing are visible

When it comes to leaks, one thing to remember is that if you notice water inside your firebox, it may not be a chimney flashing problem; instead, it could be a chimney cap problem.

Because of the location of most chimneys, you may not realise water damage once it has pierced further into your roofing. If the roof flashing is damaged, there may be continuous moisture in your loft or ceiling, which can cause wood rot as well as drywall damage.

When determining the total price of any chimney repair job, you must consider several factors. We'll look at a few of the most common types below.

Size

It comes as no surprise that the bigger the chimney, the pricier the repair. This is because a larger chimney will have higher labour and supply costs than a smaller one.

Scaffolding and Location

Because the roofer or builder would need access to your roof to finish the work, the ease of access will factor into the final cost of chimney repairs. Any difficulty getting to a chimney could raise the overall cost.

Chimney repairs frequently necessitate the use of a scaffold on your property.

Suppose your chimney is in an especially difficult-to-reach area of your roof, and much more scaffolding needs to be introduced onsite or kept up on your property for an extended period. In that case, the overall cost of the job may rise.

Some roofers would then bring their own scaffolding to the job site and include the cost of the scaffolding in the final cost, but if your roof is notably challenging to access, there may be an additional charge for any extra scaffolding required.

Chimney Flashing Prices

The table below will break down the average costs of repairing chimney flashing:

Type of Repair Chimney Flashing Cost
Replace all four aspects of flashing £400 - £500
Two storey homes £300 - £400
Replace lead flashing £800
Welding up cracks £200
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What are the Supply Costs for a Chimney Flashing Repair?

If you are debating doing it as a DIY job, then you should know about the supply costs of a chimney flashing repair. Here we will go through the cost of the materials needed to go ahead with a chimney flashing repair job.

chimney flashing repair

Before you buy the materials for a chimney flashing repair, you should bear in mind and consider the following before starting the job on your own.

Precautions for Safety

To gain access to your roof, you will need to use an extension ladder with a volunteer at the bottom to keep it steady and secure. Once you're on your roof, every step you take must be deliberate, steady, and secure, especially if you're walking at an angle.

Homeowners falling off their roofs happen more frequently than you might think.

When removing the old flashing, extreme caution must be exercised to avoid being cut or otherwise wounded by the old, potentially very sharp, pieces of metal sheet.

You will also need all the necessary equipment and materials to repair your flashing properly. Protective eyewear, bulky gloves, and gripping boots should be worn, and a roof jack should be installed in most cases.

Considerations for Tools and Materials

You'll need the right materials in addition to the right tools. To cut the flashing correctly, you should take accurate chimney measurements. Before climbing over onto the roof to begin the installation process, the metal must be measured, cut, and bent.

Considerations for Time

A single person has a finite amount of time to work on substituting their own chimney flashing.

Work should begin early in the morning before the sun has had a chance to bake your roof all day. In hot weather, shingles and adhesive heat up and become more flexible and mouldable, making them more difficult to remove. If you are not used to the heat, it may be hard to work in.

Once the shingles have been removed, please remember that the longer your roof goes without shingles or roof flashing while you work on the repairs, the more vulnerable it is to damage.

Small holes or corrosion spots in flashing could be repaired easily. Plug pinholes with roofing cement (£9 - £16) and patch holes up to 3/4 inch in diameter with a patch made from the same material as the flashing.

Lightly rub the area all around the hole with a stiff brush or sandpaper, which will cost between £3 and £9, before cleaning it. Next, cut the patch to fit the hole, secure it with roofing cement, and afterwards cover it with more roofing cement.

Chip out the old mortar and caulk along the flashing corners to renew the seals. Seal the joints between the flashing and the chimney with masonry caulk (£5 - £7).

Seal the seam between the cap and the step flashing with a urethane roofing cement or silicone caulking compound, both of which cost £6 to £14. Lift the edges of the surrounding shingles and spread roofing concretes on the flashing about 6 inches from the edge of the shingles if you're working with valley flashing.

Step flashing around the corners of a roof, with seams enclosed with caulking. Urethane caulking should be used to seal the step flashing. If you're resealing drip edging, make sure to seal beneath the shingles but not along the eaves.

To replace the flashing all-around vent pipe, first, remove the shingles from the back and sides of the flange. Pry and remove the flashing. Remove or cut any nails.

Place a new vent-pipe flashing, which costs around £15 - £20, over the vent, shove it down into place, and nail it where the shingles will cover it. Replace the shingles and use roofing cement to cover the nail heads.

The table below will break down the supply costs to repair a chimney flashing:

Supply Cost
Roofing cement £9 - £16
Stiff brush £3 - £9
Silicone caulking compound £6 - £14
Vent-pipe £15 - £20

What are the Additional Costs of Repairing Chimney Flashing?

When repairing chimney flashing, you may decide or need to have other repairs on your home, or other costs may become involved and increase the cost of your repair. Here, we will go through the different additional costs that may be added to the cost of repairing chimney flashing.

roof

Roof Repair

The fees will vary according to the type of repair and replacement required. The larger the roof, the higher the cost of maintenance or replacement.

This also applies to the height of your house, as taller structures will necessitate additional scaffolding to assist roofers while they work, raising your access costs.

Roofs with multiple levels or multiple features, such as chimney stacks or dormer windows, could indeed add time and expense to a project.

roof tiles

Suppose the roof job is going to take a few days. In that case, a temporary cover can be constructed to protect the property from the components, allowing the roof repairers to work on the roof without worrying about the weather. This will be charged in addition to the scaffolding fee.

Most cities, such as London, will have higher labour costs than cities such as Liverpool or Manchester. As a result, the overall cost will vary based on where you are.

Depending on where you live, labour costs range from £150 to £250 per day per worker. Depending on the number of hours worked, a standard flat roof garage could very well cost between £1,000 and £2,000 to build.

For further information, please refer to our guide on roof repair costs.

Roof Cleaning

Roof cleaning typically costs between £8 and £12 per m2. This will include the labour required to complete the work, as well as any necessary equipment and materials, as well as any safety equipment required to access the roof, for example, scaffolding.

roof cleaning

The general square meterage of the roof will influence the cost of having your roof cleaned. The greater the area to also be covered, the longer the work takes, and the more materials will be required.

A typical terraced roof will be 50-60 square metres, a semi-detached roof will be 65 - 75 square metres, and a fully detached home will be 100 - 115 square metres.

The cost of roof cleaning will also be determined by the number of people required to complete the job properly and safely. The number of tradespeople required to clean your roof will reflect the labour cost.

Larger roofs may necessitate the use of two people to finish the work promptly, whereas one person can usually complete smaller roof areas.

The accessibility to your roof, as well as the method being used to access it, will both have an impact on the cost of roof cleaning. The price you pay will be influenced by your ability to access the property and the roof.

The method of access used by the roof cleaning service will also be a cost consideration. Some businesses may use ladders to clean a roof, whereas others may use a scaffold tower. Larger, potentially more pricey companies will use a cherry picker to gain access to the roof.

For further information, please refer to our guide on roof cleaning costs.

Gutter Cleaning

If no scaffolding is used, the typical price of having gutters cleaned is £75 to £125 for a terraced house, £100 to £150 for a semi-detached house, and £100 to £200 for a detached house.

However, if scaffolding is required (as will be the case if working at a particular height), expect to pay between £325 and £425 for a terraced house. If you live in a semi-detached house, you should expect to pay between £375 and £425, and if you live in a detached house, you should budget between £400 and £450.

For further information, please refer to our guide on gutter cleaning costs.

Scaffolding

The average cost of assembling a scaffold tower is between £200 and £300. Scaffolding a chimney will cost around £450 to £550, £800 to £1000 for scaffolding on three sides of a semi-detached house, or £600 to £700 for scaffolding on three sides of a detached bungalow.

The form and size of the scaffolding, the amount of tradespeople employed, ease of access, and the place of your property are all cost-influencing factors when hiring scaffolding.

scaffolding

The average labour costs for erecting a scaffolding tower to repair bottom hip tiles would be between £230 and £270.

Scaffolding a bridge for just a conservatory costs £430 to £470 in labour fees, and scaffolding at the front of a property for roofing costs £400 to £450.

For further information, please refer to our guide on scaffolding hire costs.

Location

Your location in the United Kingdom will determine the cost of repairing chimney flashing. This service will be more expensive in London and the southeast due to higher business costs, including insurance and business premises.

Although the north of England, the Midlands, and some country regions of Wales and Scotland will be less expensive, the cost of repairing a chimney flashing may still be greater in some large cities.

To get an idea of the average cost, get three or four quotes from nearby chimney repair companies.

Minimum Fee

Labourers/companies may charge a minimum fee in some cases. This could be added to the total cost or counted as part of your total bill.

If you were charged by the day, it wouldn't matter if it took a day and four hours or even a day and seven hours because you'd be charged for two days of workers.

Duration

The longer it takes to repair chimney flashing, the higher the labour cost. However, the longer the hiring time frame, the more you will pay, with some homeowners having to hire repairers for a few days or others for several weeks or months.

Tradesmen Costs for a Chimney Flashing Repair

Chimneys are an important functional and aesthetic feature in many homes, and while they may appear simple in design, they often have complicated shapes that require expertise to build.

repair roof

As a result, if you start to notice any issues with your chimney, you must address the problem as soon as possible. Based on the intensity of the problem, you may need to hire a roofer or a builder to resolve it.

Damp patches on the ceilings and walls close to your chimney breast indicate a stack leak. These leaks could cause fungal decay throughout your roof timbers and, eventually, serious structural issues with your home's ceilings.

If your roof tiles are in good condition, leaks are most likely caused by defective flashings at the chimney-to-roof junction. In some cases, mortar fillets can be used instead of lead because they are less expensive, but they are prone to cracking and will not last as long.

As a result, flashings should always be replaced with new leadwork. Your roofer will install them in a tried to step pattern to provide complete protection from water and moisture invasion. After that, the lead flashing should be sealed with new mortar.

For labour, you should budget between £150 and £250 per day. A chimney flashing repairer can guess how long the work on your chimney will take. As a result, you may be charged a flat rate for the project instead of a daily fee.

Scaffolding may be required to gain access to the chimney stack. Don't be concerned; this cost will be included in your quote. Regardless of the liner style you choose, most installers work in two-person teams.

Labour costs vary depending on the area in the country. Living costs up to 20% more in London as well as the southeast of England than in the rest of the country.

How Long Does It Take to Repair Chimney Flashing?

Repairing or substituting chimney flashing is sometimes a time-consuming and labour-intensive process. And it's critical that experts install chimney flashing correctly, or your home may be vulnerable to additional water damage. How long would it take to fix a chimney flashing, though?

A repair chimney flashing usually takes about a day to complete; however, various factors can influence this and cause the process to take longer or shorter.

Scaffolding (if necessary) takes two to six hours on average, while the actual leadwork replacement should take three to five hours.

The timeframe is determined by the ease of access, the condition of the work area, and the weather conditions. The cost of labour will also vary depending on where you live. A single person has a finite amount of time to work on replacing their own chimney flashing.

Work should begin early in the morning before the sun has had a chance to cook your roof all day. Shingles and sealants heat up in hot weather and are more flexible and mouldable, making them more difficult to remove. If you are not used to the heat, it may be challenging to work in.

Once the shingles have been removed, bear in mind that the longer your roof goes without shingles and roof flashing while you work on the repairs, the more vulnerable it is to damage.

Types of Chimney Flashing Repairs

Chimney flashing would then help keep water out of the chimney. One of the most common causes of leaks is faulty or improperly installed flashing.

There are numerous types of flashing available. The place you live in, the weather conditions, the size and shape of the chimney, and the roofing material all contribute to deciding the best form of flashing for your chimney.

In this section, we will discuss the various forms of chimney flashing repairs, as well as their benefits and drawbacks.

Aluminium Flashing

One of the most popular types of flashing is aluminium flashing. It is reasonably priced and can be installed on just about any type of roof. Aluminium corrodes easily, especially when installed in places with treated shingles or lumber.

aluminium flashing

While CCA-treated roofing is uncommon, it does exist. If it is exposed to this, the aluminium will corrode as well as fail quickly. This type of flashing is available in large rolls and can be bent and cut to fit any shape. This makes it an excellent choice for contractors because it is inexpensive to buy in bulk while remaining effective.

Pros

  • Popular choice
  • It can bend and cut to fit any shape
  • Affordable

Cons

  • If exposed to CCA roofing, it will corrode

Vinyl Flashing

Vinyl flashing is a lightweight material that is a popular choice among contractors. It costs slightly more than aluminium. It's not the best material for chimneys, but it's common in areas without harsh weather.

Vinyl can become brittle and crack or break, making it an unsuitable material for areas having a lot of wet or humid weather. Vinyl is not the best material for withstanding high temperatures, which is why it is not commonly used in chimneys.

Pros

  • Lightweight
  • Good for areas with wet or humid weather

Cons

  • No good for hot countries

Steel Flashing

Steel is a bit bulky that is frequently used in the construction of roofs and chimneys. It is one of the most long-lasting flashing materials. Steel does not corrode as easily as other flashing materials

.

Most steel flashing is zinc-coated, and this can corrode even before steel itself. It takes more time because the material is heavier and requires more installation. Because it is more expensive, it is not typically used for entire roof applications, but it is ideal for chimneys.

Pros

  • Doesn’t corrode easy
  • Long-lasting

Cons

  • Expensive

Copper Flashing

Copper flashing has become one of the best materials for chimney or roof flashing available. It is lightweight, resistant to breaking or cracking, and resistant to high temperatures and weather extremes. Copper is one of the costliest metals to work with. Many people may find it prohibitively expensive.

Copper must be installed with a sealant designed specifically for this material. This sealant will provide an additional barrier of protection against water seepage. Copper is also difficult to shape, making it unsuitable for use on chimneys with rounded or difficult angles.

Pros

  • Best material

Cons

  • Expensive
  • Difficult to shape

How Much Does It Cost to Remove Chimney Flashing?

A well-installed chimney or roof flashing can last for up to 30 years. Lifespan is determined by environmental factors such as where you live, the shape and size of your chimney, and the materials used to construct it.

chimney repair

Knowing the year your house was built can help you keep track of how long your chimney will last.

Occasionally your chimney flashing repair has progressed too far and must be removed and replaced. If you need to replace your flashing, the cost can range from £750 to £1450, depending on the size of the chimney, chimney form, flashing material, and roof type.

As soon as you realise your flashing needs to be replaced, you must address the issue. Ignoring broken chimney flashing can result in additional roofing damage.

FAQs

Q: How do I know when chimney flashing needs repairing?

  • A: Failing Mortar Joints: Moisture can enter the chimney when the mortar joints begin to disintegrate. This can cause small flaws to grow much larger, potentially resulting in a chimney collapse
  • Water gets into the brick or stone of the chimney because of spalling. This can cause it to enlarge and separate from the stone or brick
  • Rust: If you start noticing that the damper is becoming more difficult to adjust or simply will not seal properly, you should inspect it to see if it is rusted
  • Ruined Walls: inspect the walls near the chimney on each level on a regular basis. It's also a smart idea to inspect after heavy rain
  • If there is excessive moisture inside the chimney, it can cause damage to the wallpaper or paint
  • Discolouration: If it is becoming slight discolouration, it is most likely due to a problem. You should consult with a professional. They will be able to quickly diagnose the problem and inform you of the necessary repairs
  • Shaling is a problem if your chimney is older and has a tiled flue lining
  • Cracks in the Chimney Crown: It's a good idea to investigate your chimney crown at least two times a year to catch any possible harm early on

Q: Should a chimney have flashed on it?

A: You may well not think chimney flashing is necessary, but it is an essential part of any chimney construction.

If you didn't have chimney flashing, you'd soon notice rainwater dripping into your attic or damp spots making an appearance on your ceiling, walls, or chimney breast.

Q: What is the best flashing for a chimney?

A: Aluminium is a popular material. Aluminium flashing is cheap and easy to install on any type of roof. It is also rust-resistant. Steel – steel is another popular material for chimney flashing.

Q: Should chimney flashing be replaced with a new roof?

A: Typically, when reroofing, it is best to replace all flashing. Old flashing may start to fail first before the life of the new roof is up. On the other hand, there are a few circumstances in which we may opt to reuse flashing.

Q: How do you seal flashing?

A: Chip out the old mortar and caulk along the edges of the flashing to renew the seals. Enclose the joints between both the flashing as well as the chimney with masonry caulk.

Urethane roofing concretes or silicone caulking composite should be used to seal the seam between the cap and the step flashing.

Sources

  1. https://verticalchimney.com/blog/chimney-flashing/
  2. https://www.priddyclean.com/chimney-flashing-repair/
  3. https://www.ajdonald.co.uk/signs-its-time-for-a-chimney-repair/
Author: Emma M

I am a Liverpool-based freelance writer with a degree in Media and Communications. I specialise in product reviews, home improvement and DIY content. I am also experienced in social media management and content marketing.