Compatibility of Dissimilar Metals & Colorbond Roofing

Contents

Compatibility of Dissimilar Metals and COLORBOND® Roofing
- Understanding Galvanic Corrosion
- Incompatible Metals with COLORBOND® Steel
Best Practices to Avoid Galvanic Corrosion
Conclusion
Contact Us about Building Your Owner Builder Kit Home
- Related posts:
Building a Granny Flat in Sunshine Coast Council
Building a Granny Flat in Logan City Council
Can You Knock Down Rebuild A Kit Home
Building A Granny Flat In Brisbane City Council
Why Not to Use Stainless Steel Fixings with COLORBOND Roofing

Compatibility of Dissimilar Metals and COLORBOND® Roofing

When it comes to roofing, especially with materials like COLORBOND® steel, understanding the compatibility of dissimilar metals is crucial to prevent corrosion and ensure the longevity of your roof. This article explores the phenomenon of galvanic corrosion, the metals that are compatible with COLORBOND® steel, and best practices to avoid issues.

Understanding Galvanic Corrosion

Galvanic corrosion occurs when two dissimilar metals come into electrical contact in the presence of an electrolyte, such as water. This creates a galvanic cell, where one metal (the anode) corrodes faster than it would alone, while the other metal (the cathode) corrodes slower ¹. This process can significantly reduce the lifespan of roofing materials if not properly managed.

Incompatible Metals with COLORBOND® Steel

Certain metals are known to cause accelerated corrosion when in contact with COLORBOND® steel. These include:

Copper: Copper pipes and fittings should not come into direct contact with COLORBOND® steel. Water runoff from copper surfaces can also cause corrosion ¹.
Lead: Lead flashing should be avoided or isolated from COLORBOND® steel. If water flows from lead onto COLORBOND® steel, it should be painted to prevent direct contact ¹.
Stainless Steel: While generally resistant to corrosion, stainless steel fixings containing copper should not be used with COLORBOND® steel ¹.

READ Statewide Secondary Dwelling Code for Queensland

Best Practices to Avoid Galvanic Corrosion

To prevent galvanic corrosion, consider the following best practices:

Isolation: Use non-conductive barriers or coatings to separate dissimilar metals. For example, rubber or plastic washers can be used with screws and fasteners ².
Proper Drainage: Ensure that water runoff from incompatible metals does not flow onto COLORBOND® steel surfaces. This can be achieved by designing the roof to direct water away from sensitive areas ².
Compatible Fasteners: Use fasteners made from compatible materials, such as zinc-coated steel or aluminum, which are less likely to cause galvanic corrosion with COLORBOND® steel ².

Conclusion

Understanding the compatibility of dissimilar metals with COLORBOND® roofing is essential for maintaining the integrity and longevity of your roof. By following best practices and avoiding direct contact between incompatible metals, you can prevent galvanic corrosion and ensure your roofing system remains durable and effective.

For more detailed information, you can refer to the BlueScope Steel guide on avoiding incompatible metals and the Corrosion Technical Bulletin CTB 12.

If you have any specific questions or need further assistance with your roofing project, feel free to ask!