Roofers Cardiff

What is Lead Flashing And How It Works

close up of lead flashing on a roof in Cardiff

Lead flashing is a type of sheet metal that is used by roofing contractors to protect the joints on your new or existing roof. The flashing prevents water from penetrating into vulnerable areas, such as where the roofs meet walls and chimneys. Lead flashing should be applied at these junctions before any build-up of elements like mortar, brick, or stonework is started.

This article will discuss more lead flashing and everything you need to know about its role in pitched / tile roofs and flat roofs.

The History of Lead Flashing

Lead flashing dates back to the Roman era when it was first used to roof temples and protect them from heavy rainfall. During this time, lead sheets were formed by hammering, cutting, bending, and soldering them together.

Today, lead flashing is more commonly used in modern construction projects as a cost-effective and durable material for waterproofing joints. Made from soft and malleable metal, lead flashing is easy to mold into different shapes or sizes to suit the needs of your specific project.

The Advantages of Lead Flashing

lead flashing protecting brick work on a property in Cardiff

There are several key advantages that make lead flashing an ideal choice for protecting vulnerable parts of your home or building. Firstly, it forms a tight seal against water penetration due to its flexible nature and pliability.


Lead flashing is also weather-resistant and can withstand extreme temperatures, making it ideal for use in both hot and cold climates. It also has a low melting point, which means it can be easily installed without the need for heat welding.


Another advantage of lead flashing is its long lifespan. When installed correctly, lead flashing can last for up to 80 years without showing any signs of wear or tear. This makes it a very cost-effective solution in the long run.

Drawbacks of Lead Flashing

Despite the advantages, there are also some drawbacks to using lead flashing in your home or building. The biggest issue with lead flashing is that it can be dangerous during installation, as it poses a health risk to anyone who comes into contact with the metal.


In addition, lead flashing can be difficult and time-consuming to install, especially if you do not have prior experience working with this material. It is also more expensive than other waterproofing options such as aluminum or zinc.


So if you are planning a construction project and need a reliable waterproofing material for your roof or walls, consider opting for lead flashing. With its many advantages, it is a great choice for protecting vulnerable areas from water damage and ensuring the long-term durability of your home.​

How Lead Flashing Is Installed

lead flashing being installed around a chimney by a roofing contractor in Cardiff

Lead flashing is most commonly used on roofs and chimneys, as well as around windows and doors. It’s important to ensure that the area is clean and dry before starting the installation process.

The first step is to cut the lead flashing to the desired size and shape, using a sheet metal cutter or tin snips. It’s important to make sure that the flashing covers all areas where water could potentially enter, such as around edges and corner joints.

Once the lead flashing has been cut, it’s ready to be installed. This typically involves applying a layer of mastic onto the area where the flashing will be placed, followed by placing the flashing into position and securing it with roofing nails.

Some projects may require additional steps for installing lead flashings, such as seams that need to be soldered together or sealing around pipe penetrations using caulking or grommets.

If you are unsure about the installation process, it’s always best to seek professional help to ensure that the job is done correctly. Improper installation can lead to water damage and other issues down the road.

Lead Flashing Maintenance

Once lead flashing has been installed, it’s important to regularly inspect and maintain it to ensure that it continues to function properly. This typically involves checking for any cracks or holes and repairing them as soon as possible.

It’s also a good idea to apply a waterproof sealant on the lead flashing every few years to prolong its lifespan and prevent any water damage. If you notice any major damage, such as large cracks or holes, it’s best to replace the lead flashing as soon as possible.

Cost of Installing Lead Flashing

The cost of lead flashing installation depends on the size and complexity of the project. On average, it can range from $500 to $1,000 for a simple roof flashing installation.

Factors That Affect The Cost of Installing Lead Flashing:

There are several factors that can affect the cost of installing lead flashing. This includes:

The size of the area that needs to be waterproofed: Larger areas will require more lead flashing and take longer to install, which will increase the overall cost.

The type of lead flashing used: There are two types of lead flashing – code 7 and code 10. Code 7 is thinner and less expensive, while code 10 is thicker and more durable.

The complexity of the project: Simple installations will be less expensive than more complex ones that involve soldering or sealing around pipes.

The geographical location: Lead flashing prices can vary depending on the geographical location. In general, it’s more expensive to install lead flashing in urban areas than in rural areas.

Lead Flashing Alternatives

If you’re looking for an alternative to lead flashing, there are a few options available. These include:

Aluminum Flashing: Aluminum is a popular choice for roof and chimney flashings because it’s lightweight and easy to work with. It’s also less expensive than lead flashing.

Zinc Flashing: Zinc is another common material used for roof flashings. It’s more durable than aluminum and can last up to 50 years with proper maintenance.

Copper Flashing: Copper is another durable option that can last up to 100 years with proper care. However, it’s more expensive than other materials and can be difficult to work with.

Stainless Steel Flashing: Stainless steel is a good choice for areas that are subject to high temperatures or direct sunlight. It’s also more durable than other materials, but it’s also more expensive.

PVC Flashing: PVC is a relatively new material that’s gaining popularity for its durability and easy installation. However, it’s not as effective in high-temperature areas and can be damaged by UV rays.

As you can see, there are a few different lead flashing alternatives available. Each has its own advantages and disadvantages, so be sure to choose the one that best suits your needs.


Overall, lead flashing is a reliable and durable waterproofing option that can help protect your home or building from water damage. By being proactive with maintenance and taking steps to ensure proper installation, you can ensure that your investment in lead flashing pays off for many years to come.​