The lead flashing on your roof and around your chimney seals the joints between the surfaces on your roof, such as between brickwork and tiles or where tiles meet to create a valley. When the flashing deteriorates, water can get in and start leaking into your loft.

So how much does it cost to have the flashing repaired or replaced around your chimney and roof? In this guide, we’ll explain the various costs involved and how to save money on your flashing repair work.

Lead flashing repair and replacement costs

How much your lead flashing repair or replacement will cost depends on the extent of the work, whether it will require scaffolding to carry out and your roofer’s rates:

These prices do not include VAT. If your roofer is VAT registered, you will pay 20% VAT on top of these prices.

The final cost of repairing or replacing your flashing and leadwork depends on:

• the amount of flashing that needs to be repaired or replaced 
• the material that was previously used 
• the material that will be used for new flashing
• the condition of the roof 
• whether scaffolding is needed 
• how long it will take the roofer to complete the work
• where you live

Labour costs vary across the country, with the highest prices in London and the south east. Check our flashing repair cost table and find your nearest town or city to get a more accurate estimate for how much it will cost to repair lead flashing in your area.

Types of flashing

There are three general types of flashing and places where it’s used on your roof:

Apron flashing

Apron flashing, or cover flashing, is used where a roof meets the brickwork of a house or chimney. Apron flashing is used on slate and tile roofs where they meet a wall, on conservatory roofs and around bay windows.

Step flashing

Step flashing allows a roof to meet where the roof is a lower height than the wall it’s meeting, usually due to a side return extension. It gets the name 'step flashing' because of the pattern created in the lead by a series of cuts that looks like the steps of a staircase. 

Using step flashing means that the brickwork can remain un-cut which looks better, offers stronger waterproofing and prevents corroding brickwork.

Chimney flashing

Chimney flashing is the flashing around the chimney to stop water from seeping through the roof at the base of the brickwork where the chimney meets the roof. This is a common area for flashing to need replacement or repair as it is very exposed to the elements.

Alternatives to lead flashing

Some people are steering clear from lead flashing because it’s toxic and harmful to the environment. Lead-free flashing is safe for the roofer to install and is suitable for water butts and other forms of rainwater harvesting.

Lead-free alternatives are also often lighter than lead, so there’s less weight on the roof for the joists to handle.

However, if you live in a ​listed building or a conservation area, you may be required to only use lead to preserve the building's authenticity. Check with your local planning authority if you’re unsure.

Popular choices for UK roofs with lead-free flashing include:

Aluminium

Well priced, popular flashing as it can be used on many different types of roofs. Aluminium flashing can be bent and cut to fit any shape. However, aluminium flashing corrodes easily.

Vinyl

This is a lightweight material that is more expensive than aluminium flashing. Although it is not suitable for colder, harsher weather, it can withstand milder wet weather. Vinyl flashing is prone to cracking.

Steel 

Steel flashing is zinc-coated and often used in the construction of roofs and chimneys. It’s a longer lasting flashing that does not corrode as easily as aluminium flashing. 

Copper 

Copper flashing is lightweight and resistant to cracking. Copper can withstand harsh climates, but it is difficult to shape as needed along the roof. Copper flashing is used with a sealant that gives an additional barrier of waterproofing.

How to tell if your lead flashing needs replacing

Lead flashing lasts a long time - up to 100 years when it can expand and contract freely - but not forever. Over decades, it can become brittle or break down, leading it to come away from the joins that it’s protecting. 

It’s a good idea to visually check your flashing yourself at least once a year if you can. This can help you spot problems before they cause issues within your home. 

Visible signs that it may be time to replace the flashing include:

• water leaking inside the loft or ceilings coming from the roof
• rust stains on the roof
• visible gaps in the caulking around the flashing
• mortar joints near the flashing disintegrating
• big gaps beginning around stone or brick
• cracks in mortar or the chimney is beginning to show signs of cracking

It’s best to deal with issues with your flashing right away, as you could end up with significant leaks into your loft the next time it rains.

How long does it take to replace flashing?

How long it takes a roofer to replace lead flashing depends on how much flashing needs replacing and whether it requires scaffolding to be erected.

For a roofer to replace all four sides of chimney flashing, this could a full day. If they need to replace all of the flashing on a two bed detached house, this could take up to 3 days.

Can you put new flashing over old flashing?

While it’s technically possible to put new flashing over old flashing, it’s not advised. Most roofers will say that it’s best to remove the old flashing before installing the new set to allow for proper sealing - otherwise you could still find leaks.

However, in some cases where a patch repair is all that’s required, a roofer may weld a small piece of lead over the old flashing. This can keep the costs down, but it’s worth bearing in mind that a patch repair won’t last as long as replacement flashing.  

Should I replace or repair my flashing?

Whether you should replace or repair the flashing around your chimney or roof depends on how badly damaged it is. If it has a small hole or there is a small, visibly corroded section that seems to be allowing water to leak inside, a roofer should be able to patch the small hole.

A roofer could use roofing cement to plug the corroded section or small hole or make a patch repair.

According to our tradespeople, these techniques should only be used on small holes that are no more than 3/4 inch in diameter.

Ready to get quotes for your lead flashing repair? Post a job on HaMuch now and we’ll put you in touch with local roofers who will be happy to help.

Estimates for common roofer jobs;

Rates for other trades