Understanding Cut Edge Corrosion and Its Impact

Cut edge corrosion attacks metal sheets. During the manufacture of metal cladding, a plastic coating (Plastisol) is added to the corrugated metal used. This coating defends the metal beneath from corrosion caused by the weather and helps it retain its appearance. Unfortunately, when cladding is cut in factories, its cut edge is left with no coating, rendering the metal exposed. After such cladding is installed as part of a construction project, cut edge corrosion can occur.

Cut edge corrosion typically takes place when corrugated metal sheets are attached to a building’s elevation or roof. The steel edges of the sheet are exposed to the air and the oxygen it contains, making them prone to corrosive processes, often made worse by pollutants and water. Eventually, the protective factory coating peels back leaving uncovered edges.

Identifying cut edge corrosion

Cut edge corrosion is commonly found at the edges of metal sheeting, at eve edges and where it overlaps. Horizontal overlaps are especially vulnerable to this kind of deterioration. While cut edge corrosion typically begins at the edges, it soon gathers speed as water moves within the inner spaces of the porous metal, allowing it to spread swiftly.

Additionally, metal guttering can experience cut edge corrosion. When gutters are fitted poorly or left blocked with debris, the dampness penetrates through any exposed metal edges and into other areas of a building. As a result, structural weakness occurs and cut edge corrosion spreads onto other roof panels and cladding.

The impact of water

When cut edge corrosion is not treated immediately, the original coating keeps peeling away from the surface of metal sheets. This enables more water to seep into the metal and rust develops. Without any protection from the plastic coating, the iron oxide rapidly eats through the cladding. As a result, the metal becomes brittle and leads to leaks and water-based damage which negatively impacts both the structural integrity of a building and its appearance. In scenarios where the damage is severe, metal cladding can end up perforated and be costly to repair. For this reason, treating cut edge corrosion quickly is advised. However, proactively protecting the cut edge of metal sheeting before corrosion can occur is always recommended.

If you’re looking to repair cut edge corrosion or to ensure it never gains a foothold in the first place, we can help. Get in touch with the Rooflock Technical Team now for expert advice and to discuss your requirements.