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The content contained in this Good Roofing Guide article is for information purposed only. While every effort is made to ensure this article is accurate at the time of posting, JJ Roofing Supplies would recommend that you always seek to use a professional roofer for completing all roofing related jobs.

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Lead Flashing Buying Guide

Purchasing lead online can be a daunting task. Lead flashing being so expensive can make you second guess yourself before purchasing. 

Lead flashing is a construction material commonly used to create waterproof seals and prevent water penetration in various building applications, particularly roofing.

Lead rolls consist of thin sheets or strips of malleable lead metal that are easily shaped to fit around roof penetrations, such as chimneys, vents, dormer windows, along roof joints and valleys.

In this guide, formulated by JJ Roofing Supplies, we walk you through all the available lead flashing codes which fit your project.

What Are Lead Codes?

Lead flashing codes are a unique comparative way to measure the thickness of the lead. 

The lead codes start from code 3 & go all the way up to Code 8. Each code has a job on the roof, used in different locations. 

Advantages Of Lead Flashing

Lead flashing is used extensively in today's housing structures, from flashings to valley gutters. The primary purpose of lead flashing is to provide a durable and weather-resistant barrier against water infiltration. They are preferred in construction due to the advantages it offers:

Durability: Lead is highly resistant to corrosion and can last for many decades, even in harsh weather conditions.

Malleability: Lead is a soft and flexible metal, making it easy to shape and form to fit the contours of a building's roof or walls.

Weight: Lead flashing is relatively lightweight, which makes it suitable for various applications without adding excessive structural load.

Sealing: It provides an effective seal against water, making it an excellent choice for critical areas where water ingress must be prevented.

Longevity: Lead flashing has a long lifespan and requires minimal maintenance.

Choosing The Correct Lead Code For Your Roof. 

As mentioned above, different lead codes are available in the market. With huge options, choosing the right choice for your roofing project is challenging. 

A commonly used lead code is code 4 lead flashing, used for soakers, flashings and vertical claddings. However, it doesn't mean that this code is just right for your project:

Here's a breakdown of different types of lead flashing codes and where they are best used:

Code 3 Lead Flashing

Thickness: Approximately 1.32mm 

Weight: (14.97 kg/m2)

Best Used: Code 3 lead flashing is typically used for smaller roofing projects or to fit soakers against small chimneys. It's suitable for areas with less exposure to harsh weather conditions.

Code 4 Lead Flashing

Thickness: Approximately 1.80mm

Weight: (20.41 kg/m2)

Best Used: Code 4 lead flashing is versatile and can be used in many applications, including larger roof areas, soakers, chimney flashings, vertical cladding and wall abutments.

Code 5 Lead Flashing

Thickness: Approximately 2.24mm (5 lb/ft²)

Weight: (25.40 kg/m2)

Best Used: Code 5 lead flashing is ideal for main roof coverings and areas more exposed to the elements, such as flat roofs, parapets, tapered valley gutters, pitched roofs, vertical cladding, dormers, bay roofs and canopies

Code 6 Lead Flashing

Thickness: Approximately 2.65mm (6 lb/ft²)

Weight: (30.19kg/m2)

Best Used: Code 6 lead flashing is the heaviest common grade for demanding applications, including parapet walls, step flashings, and areas with high wind exposure.

Code 7 Lead Flashing

Thickness: Approximately 3.15mm (7 lb/ft²)

Weight: (35.72kg/m2)

Best Used: Code 7 lead flashing is less common but can be used for specialised applications that require increased durability and resistance to extreme weather conditions. These are best used for flat roofing, parapet and tapered valley gutters, pitched roofing, dormers, bay roofs and canopies.

Code 8 Lead Flashing

Thickness: Approximately 3.55mm (8 lb/ft²).

Weight: (40.26kg/m2)

Best Used: Code 8 lead flashing is the heaviest standard grade and is suitable for highly demanding applications, such as pitched roof flashings, gutters, and flat roof junctions.

How Much Lead Flashing Do You Need?

The amount of lead flashing you need will depend on the specific project you are working on. However, there are a few general guidelines you can follow:

Overlap: Lead flashing should overlap by at least 100mm. This will ensure a watertight seal.

Length: Lead flashing should not exceed 1.5m in height.

Width: The width of the lead flashing will depend on the specific application. For example, if you are fitting a flashing against a chimney, you will need a more comprehensive piece of flashing than if you are flashing a roof valley.

What Happens When You Choose The Wrong Lead Code?

Choosing the wrong lead code can have several negative consequences, including:

Leaks: If the lead flashing is too thin, it may not be able to withstand the elements and may develop leaks. This can lead to water damage to the building structure and contents.

Splitting: If the lead flashing is too thick, it may be challenging to work with and may split during installation. This can also lead to leaks.

Reduced lifespan: Lead flashing that is not the correct code for the application may have a reduced lifespan. It may be more susceptible to wear and tear and corrosion.

Generally, it is always best to choose the lead code recommended for the specific application. This will ensure the lead flashing is durable, watertight, and best-looking.

Here are some additional tips for choosing the correct lead code:

Consider the type of surface you are flashing. For example, lead flashing on a roof must be thicker than lead flashing on a wall.

Consider the climate you live in. If you live in an area with extreme weather conditions, you must choose a lead code that is thick enough to withstand those conditions.

Consider the budget. Lead flashing can be expensive, so choosing the correct lead code for your budget is essential.

If you are still deciding which lead code to choose, it is always best to consult a professional roofer.

Lead Accessories Available at JJ Roofing Supplies

Patination Oil 

The first and most popular lead accessory is the Patination oil

Patination oil is a protective oil which halts the lead from oxidising. It keeps the lead shiny, protecting it from the outside, which often damages, discolours and corrupts the information when coming into contact with water. 

Wash a thin layer over the lead with a brush or rag to apply the patination oil. You can often see this with houses in the UK, where the lead has gone off-white. Patination is imperative to lead flash jobs for the future rather than for the minute. 

Lead Mastic

Lead mastic is a silicon compound that holds the lead in place, creating a flexible, long-lasting seal. 

Back in the day, roofers and builders would use a sand and cement mixture as the fixing; however, they soon realised that this was prone to cracking. The two most popular colours are grey and sand. One tube of lead mastic will point around five linear metres of lead per tube. 

Hall Clips

Hall clips are made from durable stainless steel, hammered into the chased wall & secured in place using a shape design. It is known that hall clips can secure the lead-up 20 times faster than traditional means. 

Hall clips are sold in packs of 50 and should be fixed with 450mm centres. Set at 450mm centres means one bag should cover around 20 linear metres of the lead chase.

Plastic Lead Tool Set 

A plastic lead tool set, commonly called a lead dresser set due to the popularity of the specific ‘lead dresser’ tool, comprises five essential lead tools to help you on your lead project. 

Lead flashing roll is a malleable material, perfect for tailoring around areas to create a compact, water-tight finish. The Lead dresser has a 50mm flat face perfect for vernally bashing the lead to mould your retired fitting. The lead bossing stick is slightly thinner than the dresser, used to set the information in intricate detail, requiring a narrower tool. 

The lead wedge is perfect for chasing into the walls & can be used in conjunction with hall clips to secure the chased lead in place. Finally, the lead bending tool is explicitly designed for bending the lead around the substrate. 

Oxyturbo Lead Welding Kit

Lead welding is used for melting two adjacent lead sheets to form a solid, durable connection. 

A popular welding kit is the Oxyturbo kit, which takes propane and oxygen to start a hot flame. This welding kit generally creates bespoke lead work for dormers, pipe fittings, box gutters, etc. Adjust the knobs for the correct flow gas to achieve your desired flame. The Oxytrubo kit, weighing only 5kg, is popular due to its compact structure, making it ideal for the roofer to carry around the roof. 

In addition, the Oxytrubo comes with almost all the components needed to start the job apart from oxygen and gas, which can also be purchased separately at JJ Roofing Supplies online or in the branch. 

Where To Buy Lead Flashing?

At JJ Roofing Supplies, we stock an extensive range of lead flashing codes. Our top-quality lead flashing and lead rolls ensure long-lasting protection for your home. Trust our expertise and shop now to enhance your roof's durability and weather resistance. Don't compromise on quality – choose JJ Roofing Supplies today!