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Feb 27, 2020

Corrugated roofing is an excellent choice for a range of domestic and industrial applications: it’s affordable, attractive, resilient and generally low-maintenance. But, because it will rain again, regular, correct maintenance is vital.

Make sure you use the right kind of screws and install them in the right way

This is probably the most important thing you can do when you inherit a corrugated roof, whether it is plastic or metal, and it’s also an important step during corrugated roof construction. Checking and making small maintenance fixes early on saves time on larger repairs later. The best screws to use for corrugated and polycarbonate roofing sheets are self-drilling, rust-resistant screws such as stainless steel or zinc-aluminium screws on all plastic or metal roofs, simply to cut down the risk of rust and leaks. It’s important to make sure they’re put in straight, seated correctly, and use a large-enough washer.

Periodically check and replace your screws and fasteners

Loose or broken fasteners should be removed completely and new ones put in to replace them. This is especially important when a structure is made of corrugated curved roof sheets, or insulated corrugated iron roofing. These kinds of roofs need to be kept dry and tightly assembled if they are to last.


Check and touch up the seams and overlaps

All corrugated roofs need to be snugly overlapped, with the seams sealed, and maintenance should include checking the joins between sheets for dents, bends and other damage. This is a task best done before the rainy season starts, to prevent moisture getting in and damaging the metal or plastic roofing sheets.

Keep an eye on the battens

Battens can go beneath or over the corrugated roofing sheet, and both types need to be checked for moisture damage or simple wear and tear every so often. Batten spacing for corrugated roofs is quite important, and must be appropriate for the coverage of the corrugated roof sheets used in the building.

Periodically check and touch up your waterproofing

This may be more important to extend the lifespan of Chromadek or galvanized corrugated roof sheets, because PVC and Perspex sheets are naturally rust-proof, but good waterproofing is essential regardless. Every so often, roofs should be checked for damage, dents, loose fasteners or sagging, and fixed appropriately. A waterproofing primer, membrane and roof sealant should then be applied to seal up any potential leak points. Filling gaps in corrugated roofs can be done with expanding foam.

Leave metal debris on the roof

After any construction or repairs, all metal objects and debris should be swept from the roof. Broken drill-bits, rivets, screws or metal shavings can all rust and might increase the risk of corrosion for the roof they lie on.

 Leave leaks unattended

A leak damages not only the roof it’s on, but also nearby walls, floors, and the contents of the rooms beneath. Learning how to fix leaks in a corrugated metal roof will save time and money over the long run. It’s straightforward: find the leak, dry the area, prime it, put down the membrane, and apply the roof sealant. It’s important to remember to cover the heads of any nails or screws with waterproofing membrane too. But be aware that some products, for example, Chromadek roofing sheets, have specific care instructions.

Let the roof get dirty or stay dirty

Corrugated plastic roofing such as Perspex or polycarbonate should be gently washed with a mild, non-abrasive cleaner. Tougher dirt such as mold, mildew or leaf residue can be scrubbed off using a nylon brush. Chromadek sheets should also be cleaned with mild, non-abrasive cleaners, and any scratches or scrapes need to be repaired promptly. For galvanized metal roofs, a nylon brush can be used to get rid of rust, grime, dirt or leaf detritus, although care should be taken not to scratch through the galvanize.


Treat a corrugated roof well and it will give you years of service. For advice on what kind of roofing is best for your structures, contact JCP Roofing at or 010 040 8324