Lead Flashing

Choosing the Right Lead Flashing for Your Roof

At County Building Supplies, we supply lead flashing for professional roofers, builders, contractors and DIY customers. Lead flashing is commonly used to create weather-resistant details around chimneys, roof junctions, abutments and other areas where roof coverings meet adjoining structures.

Our range includes Code 3, Code 4 and Code 5 lead flashing in selected widths and roll lengths, alongside lead roofing accessories.

Code 3 vs Code 4 vs Code 5 Lead Flashing

Lead flashing is available in different thicknesses, identified by lead codes. Choosing the correct code depends on the application, exposure conditions and the relevant installation guidance.

• Code 3 lead: Approximately 1.32mm thick and generally used for suitable soakers and other specified roofing details.
• Code 4 lead: Approximately 1.80mm thick and commonly specified for flashings, including suitable chimney and roof abutment details.
• Code 5 lead: Approximately 2.24mm thick and used for certain more demanding roofing applications where additional thickness is specified.

A higher lead code indicates thicker and heavier material. However, thicker lead is not automatically the correct choice for every application. Always follow the project specification and current Lead Sheet Training Academy guidance.

What Is Lead Flashing Used For?

Lead flashing provides a durable, formable weathering material for suitable roof details. Common applications include:

• Chimney flashing: Helps weatherproof the junction between a chimney and the surrounding roof covering.
• Abutment flashing: Protects junctions where a pitched roof meets a wall.
• Roof soakers: Used beneath suitable slates or tiles at certain roof-to-wall junctions.
• Roof penetrations: Suitable lead accessories can provide weathering around compatible pipes and other roof penetrations.

County also stocks a lead quick slate designed for specified pitched roof applications.

Choosing Lead Flashing Widths & Roll Lengths

County stocks lead flashing in a selection of widths, including 150mm, 240mm, 300mm, 390mm, 450mm and 600mm, depending on the lead code.

Rolls are available in selected 3m and 6m lengths, allowing customers to choose materials for different roofing projects.

The correct width depends on the detail being formed, including required upstands, laps and coverage. Check the roofing specification before ordering.

Installing Lead Flashing Correctly

Correct installation is essential for effective weather protection and long-term performance. Lead expands and contracts with temperature changes, so flashing lengths, laps and fixings must allow for movement.

Lead should be dressed and supported appropriately, with suitable fixings and detailing for the application. Excessively long lengths or incorrect restraint can contribute to cracking and premature failure.

Follow current industry guidance and use appropriate protective measures when handling and working with lead. Complex roof details should be installed by a suitably experienced professional.

How Much Lead Flashing Do You Need?

Measure the total length of the roof junction or detail requiring flashing, then determine the necessary width and lead code.

Allow additional material for laps, dressing, corners and cutting waste. For example, a 5m roof junction may require more than 5m of lead once the specified laps and detailing are included.

Check the manufacturer's and industry guidance before calculating the final quantity.

Need Advice?

Not sure which lead flashing code, width or roll length you need? Visit your local County Building Supplies branch or contact our team for product information, quantities and availability.