What is Lead Flashing?

Lead flashing is a crucial element in roofing that serves to prevent water penetration at the points where the roof meets other structures or features, such as chimneys, walls, dormers, and valleys.

Made from lead, a durable and malleable metal, lead flashing is favored for its longevity, effectiveness, and adaptability. This guide will delve into the benefits, installation considerations, and maintenance of lead flashing.

Benefits of Lead Flashing

• Durability: Lead is highly resistant to corrosion, which makes it an ideal material for roofing applications. It can last over a hundred years with proper maintenance, often outliving the materials it is designed to protect.

• Flexibility: Lead is exceptionally malleable, making it easy to shape and fit into complex roof structures and junctions, ensuring a tight and effective seal.

• Weather Resistance: Lead withstands all types of weather conditions, including UV rays, extreme temperatures, and heavy rainfall, without degrading.

• Eco-Friendliness: Lead is recyclable, and much of the lead used in flashing today is recycled, which helps reduce the environmental impact.

Installation of Lead Flashing

• Measuring and Cutting: Lead flashing must be correctly measured and cut to fit the specific areas of the roof. It usually comes in rolls and can be cut to size using snips or a knife.

• Positioning: The lead must be positioned to ensure that it overlaps the roofing material and the adjoining wall or roof feature. This overlap is crucial for preventing water from seeping through joints.

• Fixing: Lead flashing is either dressed into place and secured with clips or fixed using nails or screws. It’s essential not to puncture the lead in areas that will be exposed to water.

• Sealing: Once positioned, the edges of the lead flashing are sealed with a suitable sealant to prevent water ingress. It is also common to use lead "wedges" or "dressing" to ensure a tight fit without creating holes.

Common Applications of Lead Flashing

• Chimneys: To seal the gap between the chimney and the roof.

• Dormers: Around the base of dormer windows where they meet the roof.

• Valleys: In the valleys where two roof slopes meet.

• Abutments: Where a roof meets a vertical surface like a wall or a bigger building structure.

Maintenance of Lead Flashing

• Regular Inspections: Check lead flashing periodically, especially after severe weather, for signs of damage, lifting, or other issues.

• Cleaning: Remove any debris, moss, or dirt buildup that can retain moisture and cause the lead to corrode under the dirt layer.

• Repairs: Address any issues immediately. Small tears or punctures can often be repaired with lead patches and sealant, but larger areas may need to be replaced.

• Patination Oil: Apply patination oil after installation and periodically afterwards to prevent the oxidation of the lead, which can lead to staining and a reduction in its aesthetic appeal.

Environmental and Health Considerations

While lead is durable and effective, handling and disposal must be done carefully due to its toxic nature. It is important to:

• Use Protective Gear: Always use gloves and masks when cutting or installing lead.

• Proper Disposal: Dispose of any lead waste at appropriate recycling facilities.

• Avoid Contamination: Ensure that run-off water from lead flashing does not contaminate water collection systems.

Conclusion

Lead flashing is a time-tested solution that offers robust protection against water ingress at vulnerable points on a roof. Its durability and flexibility make it a preferred choice in many traditional and historic buildings, though its use must be handled with care due to environmental and health considerations. Proper installation and regular maintenance are key to ensuring that lead flashing continues to perform its role effectively, protecting the integrity of the building for many years.