What is Cut Edge Corrosion?

Cut edge corrosion occurs to the sheet laps and sheet ends on a profiled metal roof. Pre-finished manufactured roof sheets are cut to length to suit the building layout. Where the cuts are made is normally where the corrosion is most severe.

The corrosion develops, predominantly on roofs. It happens where the coating de-laminates and peels back from the sheet edge. This is primarily due to weathering. If left untreated, the exposed metal surface will corrode and eventually perforate. This article, on Building.co.uk, explores the problem further and looks at the scientific reasons.

On any metal roof, coating peel back is inevitable when left neglected. Subsequent corrosion is usually exempt from any roof sheet manufacturer warranty. Early detection and treatment of coating peel back and cut edge corrosion is vital. If left untreated, replacement of the roof sheets will be the only suitable method of repair.

early stages roof sheet cut edge corrosion developing — Early stages of roof sheet cut edge corrosion starting to develop.

severe cut edge corrosion paint delamination substrate failure — Severe cut edge corrosion, paint delamination and substrate failure.

roof sheet overlap treatment process basecoat application — Roof sheet overlap treatment process, basecoat application.

cut edge corrosion treatment complete — Cut edge corrosion treatment complete, guaranteed from 10 to 15 years.

How we Treat Cut Edge Corrosion

The process of repair for peel back and cut edge corrosion is simple. Following an initial site survey, which involves a thorough inspection of the areas to be treated, we attend a pre-start meeting. At this meeting we discuss the scope of works, programming of key dates and health and safety issues relevant to the works. Once the date is set, we are ready to commence.

Unlike many other contractors, we begin by power washing the localised area. This not only removes loose coatings, it also cleans the area prior to application of the cut edge protection system. We then hand grind to remove surface corrosion and feather back the factory coating. This creates a tight edge which will be encapsulated with the cut edge system.

For a mid-sheet overlap, firstly, we apply sealant which forms a fillet to the lap joint followed by the basecoat. This is then over-coated with the final topcoat, in a colour to compliment the existing roof sheets. For the gutter edges we apply a basecoat followed by a topcoat. For a higher standard of finish, using tape, we mask off the outer edges prior to top-coating. This creates a perfectly straight tram-line, giving you a much neater finish.

mid sheet cut edge masking — Using tape to mask the area to be painted, results in a more professional finish.

cut edge corrosion treated roof grey paint — Steel roof ridge cap edges treated for corrosion.

Step by Step Treatment Process

Inspection and assessment to identify the extent of coating peel back and corrosion.
Surface preparation including a high pressure wash down of the area to be treated.
Removal of any loose paint and corrosion by hand grinding and wire brushing.
Application of a gun-applied mastic to seal the mid-sheet overlaps.
Re-coat using basecoat followed by brush or roller applied topcoat to the specified thickness.

brush applying base coat mastic beading overlap cut edge treatment technician hi vis bib

Cut Edge Corrosion Treatment Process Illustrated

cut edge corrosion treatment process explained

In all cases our works will be undertaken without disruption in adherence with our SafeContractor code, maintaining the highest standards of health & safety

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to discuss your Cut Edge Corrosion Treatment Requirements

D&D Industrial Coatings Ltd are an approved contractors for major UK paint manufacturers