Cut Edge Corrosion
Progressive corrosion at the cut edges of profiled steel cladding — the leading structural risk on UK industrial buildings.
A Survey Should Come Before a Specification
Before any system is recommended, a condition survey establishes whether refurbishment is appropriate for your specific building — substrate condition, corrosion extent, ingress sources and adhesion performance. A survey is the evidence base for every decision that follows.
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If a condition survey has already been carried out, submit your details and we will review the findings, determine the appropriate system and connect you with a suitable approved applicator.
What Is Cut Edge Corrosion?
Cut edge corrosion is the most structurally significant form of deterioration on profiled steel cladding in the UK. When steel coil is processed in the factory, the continuous coating line applies protection to the flat surface — but when sheets are cut to length, the raw steel is exposed at the cut edge. There is no factory-applied edge protection. On UK buildings, where driven rain, coastal salt and industrial pollutants are common, moisture attacks this exposed edge and corrosion begins. Without treatment, it tracks beneath the coating and along the profile, undermining the protective coating from below. Unlike surface fading, cut edge corrosion cannot be resolved by simple over-coating — the active rust must be converted and the edge sealed before any top coat is applied.
What Causes It?
All profiled steel cladding has cut edges — it is a manufacturing characteristic, not a defect. The rate at which corrosion develops depends on atmosphere (coastal and industrial environments are highest risk), the original coating system weight, and whether any edge sealant was applied at installation. Many buildings from the 1980s and 1990s had no edge treatment whatsoever. Buildings where the roof laps have not been resealed, or where sealant has failed, show accelerated edge corrosion due to water pooling.
How Serious Is It?
Severity: High. Action required within 3-6 months. This problem is progressive and will worsen without intervention, potentially leading to structural damage or internal water ingress.
What Happens If Ignored?
Cut edge corrosion spreads beneath the coating, undermining sheet integrity. Untreated, it leads to perforation, water ingress, and eventual panel replacement requirements at significantly higher cost.
How Is It Assessed?
Forti Nova's assessment process includes: visual survey of affected elevations, identification of corrosion sources or ingress routes, adhesion testing where coating failure is present, substrate condition inspection, and documentation with photographic evidence. For cut edge corrosion, roof-level inspection maps corrosion extent across elevations.
What Are The Refurbishment Options?
Cut edge corrosion treatment is appropriate when the corrosion is active at the edges but has not perforated the main sheet area. Treatment combines rust conversion to stabilise the active corrosion, an inhibitive primer to prevent further spread, and a flexible top coat to seal the edge. It can be applied independently as a targeted repair, or as part of a full facade refurbishment programme. Where the main sheet area is being over-coated as part of the same project, system selection — including whether TopSpray 35 from Prokol Protective Coatings is appropriate for the main surfaces — is confirmed through the site assessment process. TopSpray 35 may be considered for the main sheet over-coat where a premium warranted outcome is required, subject to substrate condition and specification.
When Is Replacement Necessary?
Where corrosion has spread significantly from the edge into the main sheet, or where sheet profiles have perforated, coating treatment alone is not appropriate. Panel section replacement may be required before any protective coating programme. An inspection to map the extent of edge corrosion is always recommended before specifying treatment.
What Happens Next?
Addressing cut edge corrosion requires a structured approach. Follow this diagnostic pathway to ensure the correct remediation strategy is specified for your building.
Commission Professional Survey
A qualified surveyor must assess the extent of the problem, identify the root cause, and determine substrate condition. This is a critical first step before any system is specified.
Learn About SurveysReview Survey Findings
The survey report provides a detailed analysis of the building's condition, including photographic evidence and testing results. This report forms the basis for all specification decisions.
Roof Condition SurveysRequest a Specification & Assessment
Based on the survey findings, Forti Nova's technical team and approved applicator network will develop a detailed specification and provide project pricing. This is the final step before programme commencement.
Request AssessmentRecommended Survey Type
Professional survey identifies the extent of the problem, root cause and appropriate remediation strategy before any system is specified.
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Need an Assessment?
If you're experiencing cut edge corrosion, a site assessment can help determine the right refurbishment approach for your specific building.
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