The Difference Between Code 3 and Code 4 Lead Flashing

Lead flashing is an integral part of roofing, especially in water-proofing junctions where the roof meets other surfaces, like chimneys, walls, or other roof sections.

The lead used for roofing is categorized into different codes, which refer to the thickness and weight of the lead sheet. Code 3 and Code 4 are two common specifications used in roofing projects, each suited for different applications based on their physical properties. Here’s a detailed comparison to help clarify when and why one might be chosen over the other.

Code 3 Lead Flashing

• Thickness: Code 3 lead flashing is approximately 1.32 mm thick.

• Weight: It weighs around 15 kilograms per square meter.

• Suitability: Code 3 lead is generally used for soakers and lightweight flashing applications. Soakers are used underneath tiles and slates at wall abutments, around chimneys, and at the junctions of roof and vertical surfaces where higher flexibility is required.

• Flexibility: Due to its thinner nature, Code 3 lead is more flexible and easier to work with, making it ideal for complex shapes and tighter spaces on roofs.

Code 4 Lead Flashing

• Thickness: Code 4 lead flashing is thicker, about 1.80 mm.

• Weight: It weighs approximately 20.41 kilograms per square meter.

• Suitability: Code 4 lead is commonly used for flashings, pitched valley gutters, dormers, and vertical cladding. Its additional thickness makes it more suitable for these areas that require a higher level of durability and resistance to thermal movement and water penetration.

• Durability: Being thicker, Code 4 lead offers better durability and a longer lifespan compared to Code 3. It withstands mechanical stresses better and is less prone to tearing.

Choosing Between Code 3 and Code 4 Lead Flashing

The choice between Code 3 and Code 4 lead flashing depends on the specific requirements of the roofing project:

• Application Area: For detailed work that requires flexibility, such as in tight corners or intricate designs, Code 3 is preferable due to its malleability. For areas that bear more water flow or where greater durability is needed, Code 4 is the better option.

• Longevity and Performance: Consider the expected lifespan and performance demands. Code 4’s thickness provides a stronger barrier against harsh weather conditions, making it a wise choice for exposed areas or regions with severe weather.

• Budget Constraints: Code 4 lead is generally more expensive than Code 3 due to its greater material density. Budget considerations might influence the choice, especially in large-scale projects.

Installation Considerations

Regardless of the code selected, proper installation is crucial to ensure the effectiveness and durability of the lead flashing:

• Handling and Safety: Lead is heavy and requires careful handling to prevent injury. Safety gear should be worn to protect from lead exposure.

• Fixing and Dressing: Both types of lead should be correctly dressed and fixed into place, ensuring there is sufficient overlap to prevent water ingress.

• Maintenance: Regular inspections can help catch and rectify issues like lifting or cracking early, irrespective of the lead code used.

Environmental and Health Considerations

Lead is a toxic material, and precautions are necessary to manage its environmental and health impacts:

• Usage of Protective Equipment: Always use gloves, masks, and proper ventilation when working with lead.

• Disposal: Dispose of lead waste responsibly. It should be recycled at designated facilities.

• Runoff Management: Consider the potential for lead contamination in water runoff, particularly for buildings with rainwater harvesting systems.

Conclusion

Choosing between Code 3 and Code 4 lead flashing largely depends on the application's specific demands concerning durability, flexibility, and exposure to elements. Understanding the characteristics and appropriate usage of each can help ensure that your roofing project is successful, safe, and long-lasting. Always consult with or hire experienced professionals for installation, as proper handling and placement are critical for maximizing the benefits of lead flashing.