Cut edge corrosion treatment is the professional sealing and protection of exposed edges on profiled metal roof sheets, stopping rust and water ingress without the cost of a full re-roof. Cut edge corrosion is the rusting and deterioration that occurs along the exposed edges of profiled metal roof sheets — most commonly where the steel was cut to size during manufacture or installation, removing the factory-applied protective coating. A professional treatment seals and protects these vulnerable edges, stopping leaks and extending the roof’s working life without the cost or disruption of a full re-roof.
Key Facts: Cut Edge Corrosion Treatment
- What it is: A multi-coat protective system applied to corroded sheet edges to halt rust and prevent water ingress.
- Common roof types affected: Profiled steel cladding, composite panels, plastisol-coated and galvanised sheets.
- Warning signs: Rust staining on walls or gutters, flaking paint along sheet overlaps, visible orange corrosion at sheet edges.
- Treatment lifespan: A properly applied system typically carries a guarantee of 10–25 years, depending on the product and specification.
- Disruption: Work is carried out from above — the building stays fully operational throughout.
What Causes Cut Edge Corrosion?
When profiled metal sheets are manufactured, the factory coating (usually plastisol or polyester paint) covers the flat surfaces but not the cut edges. These unprotected edges are exposed to rain, UV light and atmospheric pollutants from day one. Over time — often within 5–10 years on older coatings — the steel begins to oxidise. The corrosion creeps beneath the factory finish, lifting it away from the substrate, which accelerates the problem further.
Certain factors make cut edge corrosion worse:
- Coastal or industrial locations — salt-laden air or chemical pollutants speed up oxidation.
- Poor original installation — overlaps that trap standing water or debris.
- Age — buildings from the 1980s and 1990s with early plastisol coatings are particularly prone.
- Lack of maintenance — blocked gutters and moss growth hold moisture against sheet edges.
How Cut Edge Corrosion Treatment Works
A professional treatment follows a well-established process. Here is what to expect:
- Roof survey and condition report — We inspect every sheet edge, lap joint and fixing to assess the extent of corrosion and confirm the roof is structurally sound enough for treatment.
- Preparation — Loose rust, flaking coatings and debris are removed by wire brushing or mechanical abrading. The surface must be clean and dry for the system to bond.
- Primer coat — A rust-inhibiting primer is applied to all prepared edges, sealing the exposed steel.
- Reinforcement (where needed) — On heavily corroded or perforated edges, a reinforcing membrane or bandage is embedded into wet coating to bridge gaps and restore the sheet profile.
- Top coat — One or two finishing coats of a flexible, UV-stable protective coating are applied over the primed edges. This forms a durable, weather-tight seal.
The entire process is carried out from the roof surface using safe access equipment. There is no need to strip sheets, and the building below remains fully operational — an important consideration for warehouses, factories and retail units that cannot afford downtime.
Treatment vs. Re-Roofing: Which Do You Need?
Cut edge corrosion treatment is not a universal fix. It works when the roof sheets themselves are still structurally intact — the corrosion is confined to edges and laps. If sheets are perforated across their faces, or the purlins beneath are compromised, a more extensive refurbishment or partial re-sheet may be required.
For the majority of commercial buildings we survey, treatment is the right option. It typically costs a fraction of a full re-roof and can be completed far more quickly. Combined with a liquid roof waterproofing system across the wider roof area, it can add decades of serviceable life to an ageing building.
What to Look for in a Contractor
Not all cut edge corrosion treatments are equal, and neither are the contractors who apply them. When choosing a specialist, check for:
- Product accreditation — Are they approved to install the system they are quoting? Manufacturer-backed guarantees require approved applicators.
- Roof survey included — Any reputable contractor will survey the roof and provide a written condition report before quoting, not just price from photographs.
- Insurance-backed guarantees — A guarantee is only worth something if the company is still trading. Look for third-party warranty protection.
- Relevant case studies — Ask to see completed projects on similar building types. Our case studies page shows examples of the work we carry out on commercial and industrial roofs across the UK.
We provide roof coatings in Norwich and roof coatings in Cambridge, with specialist cut edge corrosion treatment services for commercial and industrial buildings across the region.
Frequently Asked Questions
How do I know if my roof has cut edge corrosion?
The most obvious sign is rust-coloured staining running down the building’s walls or into the gutters. From roof level, you will see orange or brown corrosion along the bottom edges of sheets where they overlap, and the factory paint coating will be bubbling or flaking. If you are unsure, we can carry out a free roof survey to assess the condition — get in touch here.
Can cut edge corrosion be treated on an asbestos cement roof?
Cut edge corrosion is specific to metal-profiled sheets. However, asbestos cement roofs develop their own weathering problems — cracking, delamination and water absorption. We offer specialist asbestos roof waterproofing and encapsulation for these buildings, which follows a similar over-roofing principle.
How long does the treatment last?
This depends on the system specified, the roof’s condition and the building’s environment. Most leading systems carry manufacturer-backed guarantees ranging from 10 to 25 years. We always recommend the specification that matches the building owner’s long-term plans.
Will my building need to close during the work?
No. All work is carried out externally from the roof surface. There is no need to vacate the building, move stock or halt operations. For occupied buildings such as schools, offices and retail units, this is often the deciding factor in choosing treatment over re-roofing.
Does cut edge corrosion affect insurance or property surveys?
It can. Surveyors increasingly flag untreated cut edge corrosion as a building defect, and insurers may note it as a maintenance concern. Treating the problem proactively protects the building’s value and avoids complications during sales, lease renewals or insurance reviews.
Get a Free Roof Survey
If you have noticed rust staining on your building or it has been some years since the roof was last inspected, we would recommend a professional survey. We provide free, no-obligation condition reports for commercial and industrial buildings across East Anglia and nationwide. Call us or request a quote online to book your survey.