Cut Edge Corrosion

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What Is Cut Edge Corrosion on Metal Sheeted Roofs and How Can It Be Treated?

Metal sheeted roofs are a popular choice for industrial and commercial buildings due to their durability, strength, and longevity. However, like any building material, they are not immune to wear and tear.
One of the most common issues affecting metal roofs over time is cut edge corrosion—a problem
that, if left untreated, can lead to costly repairs and structural damage.

What Is Cut Edge Corrosion

Cut edge corrosion occurs at the edges of metal roofing sheets, where protective coatings have been cut or compromised during installation. These edges are typically exposed to the elements and are particularly vulnerable because they lack the full protective layer that covers the rest of the sheet.

Over time, moisture, oxygen, and pollutants penetrate these exposed edges, causing the metal to oxidise and corrode.

This type of corrosion is especially common on coated steel roofing products, such as plastisol-coated sheets, where the factory-applied coating has been cut during manufacturing.

Signs of Cut Edge Corrosion

Early detection is key to minimising damage. Common signs include:

∙ Peeling or flaking of the protective coating at sheet edges
∙ Rust staining along lap joints and gutters
∙ Visible metal corrosion at exposed edges
∙ Water ingress or leaks in affected areas

Why It Matters

If ignored, cut edge corrosion can spread from the sheet edges to the lap joints—where sheets overlap—and compromise the roof’s weatherproofing. This can result in water penetration, insulation damage, structural integrity of the roof, and ultimately, the need for partial or full roof replacement.

How to Treat Cut Edge Corrosion

Fortunately, there are effective methods for treating and managing cut edge corrosion. Here is our typical process:

1. Inspection and Cleaning
We will begin by assessing the extent of the corrosion. The affected areas are then cleaned to remove debris and loose coating using a pressure washer and isopropyl alcohol.

2. Rust Treatment
To stop further corrosion and we will then prepare the surface using wire brushes & grinders.

3. Sealing and Coating
Specialist sealants and flexible edge protection systems are applied to reseal the cut edges and lap joints. These coatings are designed to move with the metal and provide long-term waterproofing and protection against progressive corrosion.

Preventing Future Corrosion

To avoid future issues:

∙ Ensure all cut edges are sealed at the time of installation
∙ Schedule regular roof inspections and maintenance
∙ Apply protective coatings as part of a preventative maintenance plan

Conclusion

Cut edge corrosion is a common but if found early enough manageable issue with metal sheeted roofs. Early identification and treatment are crucial to extending the life of your roof and avoiding costly repairs. If you suspect your building may have signs of cut edge corrosion, consult with us for a professional assessment and tailored treatment plan.

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If you’re looking for a dependable commercial roofing partner with national reach and local expertise, get in touch with us today. We’re here to help — no matter the size or complexity of your project.

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