What screws should I use for fibre cement roof sheets?
For fibre cement profile roof sheets going onto a steel frame, use a self-drilling fibre cement screw with a sealing washer like this one. The self-drilling point fixes into light section steel up to 5mm, and the EPDM washer keeps the fixing watertight.
Do these fibre cement sheet screws need pre-drilling?
No. The self-drilling point cuts its own hole through steel up to 5mm thick, so you can drive straight through the sheet and into the purlin in one action. That saves a step on every fixing across the roof.
What is a BAZ washer?
A BAZ washer is a sealing washer made from an EPDM rubber bonded to a stainless steel top cap. As you tighten the screw, the EPDM compresses over the fixing hole and forms a watertight seal, while the stainless cap protects the rubber from the weather.
Can I use these to fix fibre cement sheets to timber?
No. These have a self-drilling point for light section steel, not a timber thread. For fixing fibre cement sheets to timber purlins, use a screw with a timber point instead.
How thick a steel purlin will they drill into?
The self-drilling point is rated for light section steel up to 5mm thick. For heavier steel beyond that, you would need a different fixing.
Are these screws suitable for exterior use?
Yes. The exterior silver organic coating carries a corrosion class 3 rating and withstands over 1,000 hours of salt spray, so they suit exposed roofing and cladding on farm and industrial buildings.