Replace Leadwork on Chimney Cost: How Much to Expect?
Last updated 11th February, 2025
How much does lead chimney flashing cost?
If your chimney base is needing repair and you're looking for chimney flashing repair or replacement prices, look no further. This article covers all you need to know about lead chimney flashing.
We discuss the cost of roof flashing repair and chimney lead work, including labour fees, timescales and much more!
We'll get you up to speed in a flash below!
Table of Contents
What is Chimney Flashing?
Chimney flashing is a crucial component of your roofing system, designed to create a waterproof barrier around the base of the chimney stack. This metal sheet is meticulously installed to prevent water from seeping into the roof and causing structural damage.
By securing the junction between the chimney and the roof, chimney flashing plays a vital role in maintaining the integrity of both the chimney and the roof. Without proper flashing, water can infiltrate, leading to leaks, mold growth, and even compromising the stability of the chimney itself.
How Much Does it Cost to Repair or Replace Lead Flashing?
Lead is used on many areas of the house, particularly on the roof around a chimney base (called chimney flashing), where a wall meets roof tiles, or in a roof valley. One of the oldest building materials still in use today, if installed correctly, lead will outlast the building itself! However, it is expensive and will usually need to be installed by an experienced professional as opposed to a local handyman or as a DIY project.
So why use lead for chimney flashing?
Lead is extremely durable, so durable in fact that most issues with leadwork are caused by poor installation, with the most common problem being leadwork simply coming loose from the wall and leaving a gap for rainwater. Timely chimney repair is crucial to avoid structural damage.
But over time, leadwork will eventually split due to the exposure to the great British weather, and the actual leadwork replacement itself can take about three to five hours depending on factors like access ease and weather conditions.
Lead comes in rolls but should never be installed in lengths over 1.5 metres, less for thin lead rolls. For long runs, the lead strips should be overlapped to allow for thermal expansion and prevent splitting after just a few years.
If replacing or repairing any chimney flashing leadwork, you should be prepared to replace some roof tiles at the same time. Disturbing roof tiles during chimney flashing repair will often lead to broken tiles so it makes sense to have some spare tiles handy before starting the job. You can also get the roofer to do a full roof inspection to check for damaged tiles or roofline products.
Lead is manufactured in 3 common thicknesses (3-5mm) but the thicker the lead the better, though obviously, thicker lead is also more expensive! Lead can be shaped by welding or by beating. If the lead is to be shaped by beating with wooden tools then the thickest lead should be used, but for welding thinner can be used no problem.
The lead is fixed to the wall by lead plugs which are wedged between the courses of bricks. Then cement is used to fill any gaps and prevent water penetration. The three main different types of leadwork are a lead apron, step cover flashing and a lead back box on a chimney.
Lead apron flashing is the easiest job but step flashing is much more difficult as it requires cutting in angles to match the slope of the roof.
Replacing a chimney back box can be difficult and expensive as it often involves removing lots of tiles. But the most expensive part of any lead replacement job is the repair cost, which includes the cost of the lead itself, closely followed by the access up to the roof which often involves scaffolding.
The most common problem with replacing lead chimney flashing is damage to the roof tiles which need removing as part of the job. Roof tiles are generally cheap but if a lot of them are damaged, particularly if they are cemented in, this can mean substantial additional labour costs!
However, the most serious problem is fires — patch repairs on lead need heat which, in inexperienced hands, can lead to disastrous roof fires. Lead is very heavy too, so for larger sheets do not expect to be able to move them around a roof on your own!
Lead Flashing Prices
The average cost of replacing leadwork around a chimney is usually in the range of £350-£800 depending upon the position of the chimney, whether or not scaffolding will be needed, and whether your house is single or 2-storey.
Most roofline workers operate in pairs and will usually charge around £200-£300 per day. Usually the job will be completed within a single day, and in most cases will be only half a day so labour costs are not considerably expensive.
There are various chimney repair jobs, each with its own associated costs, such as repointing, replacing flashing, and chimney pot repairs. It's important to determine whether a full rebuild is necessary or if minor repairs will suffice.
Here are a few average repair costs for replacing and repairing leadwork around a chimney:
| Repair or Replace | Scaffolding? | Avg. Cost | Duration |
|---|---|---|---|
| Repair | No | £200 | Half a day |
| Repair | Yes | £500 | 1 day |
| Replace | No | £350 | Half a day |
| Replace | Yes | £700 | 1 day |
Cost Breakdown
Individual costs for replacing leadwork around a chimney with scaffolding required - Total Cost: £700
Materials
£280
Tradesmen
£140
Scaffolding
£280
Cost Affecting Factors of Chimney Flashing Repair
The overall cost for your flashing repair will depend on a few different factors:
- Amount of new lead required
- Scaffolding costs (if required)
- Type of chimney
- Ease of access to the chimney. Maintaining the chimney breast is crucial to avoid structural problems, such as damp patches on ceilings and walls, which can indicate leaks.
Repair Options: When considering chimney repairs, it's important to factor in the associated costs and logistical challenges. Scaffolding is often necessary for safe repair work, and difficult access can significantly increase overall costs. Estimates for various repair tasks should include scaffolding expenses to provide a comprehensive quote for chimney repair services.
Repair Options
When it comes to chimney flashing repair, the approach depends largely on the extent of the damage. For minor issues, such as small cracks or holes, patching can be an effective solution. However, more significant damage might necessitate a complete replacement of the flashing system.
In some instances, the roof tiles surrounding the chimney may also need to be replaced to ensure a watertight seal. Given the complexity and potential risks involved, it is essential to hire a professional roofer or chimney specialist. They can accurately assess the damage and recommend the most appropriate repair strategy, ensuring the longevity and effectiveness of the repair.
The Replacement Process
Replacing chimney flashing involves several meticulous steps to ensure a durable and watertight installation:
- Inspection: A comprehensive inspection of the chimney and roof is conducted to evaluate the damage and determine the best course of action.
- Removal: The old, damaged flashing is carefully removed, and the area is thoroughly cleaned and prepped for the new installation.
- Measurement: Precise measurements of the chimney and roof are taken to ensure the new flashing fits perfectly.
- Installation: The new flashing is expertly installed, with all seams and edges sealed to prevent water ingress.
- Testing: Finally, the new flashing is tested to confirm it is watertight and functioning correctly, providing peace of mind that the repair is effective.
Benefits of Replacement
Investing in the replacement of chimney flashing offers several significant benefits:
- Prevention of Water Damage: A new flashing system effectively prevents water from entering the roof, protecting the chimney and surrounding structure from damage.
- Improved Safety: Properly maintained chimney flashing reduces the risk of accidents and injuries related to water damage and structural instability.
- Increased Property Value: A well-maintained roof with new flashing enhances the property’s appearance and value, making it more attractive to potential buyers.
- Reduced Maintenance: New flashing reduces the need for frequent repairs, saving time and money in the long run.
Building Regulations & Planning Permission
In the UK, replacing chimney flashing may require adherence to building regulations and, in some cases, planning permission. The specific requirements can vary based on the extent of the work and the property’s location.
It is crucial to consult with local authorities and engage a professional roofer or chimney specialist to ensure compliance with all relevant regulations. This step not only ensures the legality of the work but also guarantees that the replacement is carried out to the highest standards, safeguarding the integrity of your home.
DIY Chimney Flashing Repair
Lead chimney flashing repair is not exactly a walk in the park and isn't recommended for a DIY project unless you have very solid experience and expertise. Apart from the obvious dangers of working at height, lead repair also requires heat, which can lead to a roof fire if not carried out properly.
In less extreme scenarios, you may end up damaging roof tiles or incorrectly fitting the repaired or replaced flashing and run into more costly issues down the line. Ultimately, this is a DIY job that comes with a whole lot of risk, and is best left to the professionals.
FAQs
The average cost will be around £600 to £800. If the chimney is located on the roof ridge, then the scaffold will cost a lot more. To just re-fix existing leadwork by raking out loose mortar to 15 metres and re-pointing, plus replacing any loose plugs as required, excluding any scaffolding fees, then you are looking at around £250-£500.
There are other options for flashings, but lead will last longer and age more beautifully than any cheaper substitutes, outlasting any alternative building material, making it the best value in the long run, even though at first it may appear more expensive.
Investigate contractors thoroughly before hiring them to do any work by making sure they are a licensed and insured, with the relevant accreditations and trade associations. Always ensure you get a landline telephone number and real physical address,tradesman who just supply mobile numbers are virtually untraceable. Also check they have relevant experience working with leadwork - there is no point hiring a roofer that does great work on thatched roofs if you need your leadwork replacing!
Roofers tend to specialise in certain areas so ensure their experience is relevant to the job you need doing. Finally look at examples of their previous work if possible. Companies which are happy to show you their previous work are much more likely to be genuine and dependable. Any roofer that refuses to show you previous work or provide references from previous customers should immediately set alarm bells ringing!
Sources
https://www.roofingmegastore.co.uk/blog/midland-lead-flashing-price-guide.html
https://www.diydoctor.org.uk/projects/chimney_flashing_part1.htm
https://www.roofingsuperstore.co.uk/browse/lead/code-5-lead-flashing.html
https://www.leadworx.com/shop/chimney-flashings/lead-front-apron-chimney-flashing/
