Early edge blistering
Moisture reaches the exposed cut edge and begins lifting the factory finish; early treatment can limit the spread when the steel remains sound.
Profiled metal roof failure
Cut-edge corrosionrepair.
A problem-led route from early edge blistering to perforation—showing when preparation and treatment are viable and when sheet work is necessary.
Direct answer
Cut-edge corrosion is treatable where adequate sound steel remains. The real decision is how far corrosion has travelled beneath the coating and whether the sheet edge can still support a durable repair.
Problem → diagnosis → response
How the defect affects the repair scope.
Rust creeping beneath coating
Visible corrosion may extend beyond the obvious line, so preparation must reach a stable, well-adhered boundary.
Corrosion at end laps
Overlapping sheets retain moisture and combine edge deterioration with a waterproofing detail that may also be failing.
Perforated sheet edges
Holes and material loss change the work from simple treatment to repair, reinforcement or sheet replacement.
Recurring treated corrosion
Failure can return where preparation was insufficient, moisture paths remain or the repair system was incompatible.
Adjacent gutter exposure
Standing water, overflow and persistent wetting at eaves can accelerate deterioration and must be addressed with the roof edge.
Repair, refurbish or replace
How repair and refurbishment options are compared.
Prepare and treat
For early or moderate corrosion where sound steel remains and a specified edge system can bond reliably.
Repair and protect
For more developed local deterioration requiring compatible reinforcement or sheet-edge repair before protection.
Replace affected sheets
For advanced perforation, extensive section loss or a remaining substrate unable to support a reliable repair.
When this route is not enough
Edge treatment alone is unsuitable where perforation or section loss is advanced, the end lap is failing extensively, the sheet is structurally compromised or recurring wetting remains unresolved.
How the work is specified
From inspection findings to a scope of work.
- 01Map corrosion by elevation, sheet run and end-lap position.
- 02Remove loose coating and corrosion to reveal the true affected extent.
- 03Assess remaining steel, perforation and the condition beyond the visible edge.
- 04Check laps, fasteners, gutters and recurring moisture sources.
- 05Specify a compatible primer, edge repair and wider coating where needed.
- 06Inspect preparation and completed detail before recording the treated zones.
Clear answers
Metal roof questions, answered
What is cut-edge corrosion?
It is corrosion that starts where profiled metal sheets were cut and the steel edge is less protected. Moisture can then creep beneath the factory coating and cause lifting, rust and eventually material loss.
Can cut-edge corrosion be repaired?
Often, when sufficient sound steel remains. The affected edge must be prepared, assessed and treated with a compatible system. Perforation or advanced section loss may require repair or sheet replacement.
Can you just paint over cut-edge corrosion?
No. Loose coating and corrosion need removal or treatment to the specified standard, and the remaining steel must be suitable. A cosmetic coat over active corrosion is unlikely to be durable.
Why does cut-edge corrosion come back?
Common causes include incomplete preparation, corrosion remaining beneath coating, persistent wetting, failed end laps, incompatible materials or a repair used beyond the condition it can support.
Does cut-edge corrosion cause leaks?
It can, especially once perforation develops or corrosion affects end laps. However, nearby laps, fasteners, gutters and rooflights should also be checked because several water paths can coexist.
Should the whole roof be coated at the same time?
Not automatically. A survey should determine whether edge treatment alone is proportionate or whether wider coating breakdown justifies a whole-roof protective system.
Metal Roof Refurbishment Cluster
Related metal roof resources
Technical guidance across the metal roof condition-to-coating lifecycle — corrosion, cut-edge failure, repairability, preparation, protective coating, inspection and cost.
Your roof. Your next step.
How far has the corrosion progressed?
Send the postcode, roof type, approximate area, visible defects and wide plus close-up photographs. We will help establish the next technical step.