Profiled steel and aluminium roof sheeting is one of the most demanding environments for a fastener: the screw must drill its own hole through hardened sheet steel, clamp the sheet firmly against the purlin, and keep the joint watertight for decades - while coping with thermal movement, wind uplift and corrosion from both sides of the roof.
Why Fastener Selection Matters in Metal Roofing
Up to 80% of metal roof leaks trace back to the fastening point, not the sheet itself. An under-sized point burns out before penetrating the purlin; an over-drilling point strips the thread and loses clamp load; a washer that is over-compressed cracks within a few seasons. Choosing a matched drill point, thread and washer combination for the total steel thickness in your build-up is therefore the single most important specification decision on a metal roof.
Recommended Fastening Solutions
- Hex Washer Self-Drilling Screws with EPDM Washer - the industry standard for fixing trapezoidal and corrugated roof sheets to steel purlins; the bonded EPDM washer seals the drilled hole against wind-driven rain.
- Zinc-Tin Alloy Coated Roofing Screws - a sacrificial coating that protects the carbon-steel screw even where the coating is damaged by drilling, ideal for agricultural and industrial buildings.
- Ruspert Coated 304 Stainless Steel Bi-Metal Screws - for coastal or high-corrosion sites where ordinary coated screws cannot guarantee the design life of the roof.
- EPDM Sealing Washers - replacement and upsize washers for refurbishment and over-cladding projects.
Typical Applications
- Trapezoidal and corrugated steel roof sheeting on portal-frame warehouses and factories
- Standing seam and composite panel side and end laps
- Flashings, ridge caps, gutters and eave closures
- Over-roofing and refurbishment of existing profiled roofs
- Wall cladding and liner panels
Installation Guidelines
- Always match the drill point (#2, #3, #4 or #5) to the combined thickness of sheet plus purlin - the point must protrude at least three full threads beyond the steel before threading starts.
- Drive with a depth-setting nose cone: the EPDM washer should be compressed to roughly half its original thickness, visibly squeezing slightly at the edges, but not cut or rolled over.
- Keep screws perpendicular to the sheet; an angled screw cuts an oval hole that will leak.
- Do not exceed the recommended maximum fastening spacing for the wind zone, and add extra fixings at sheet ends, corners and perimeter zones.
Why Choose BuildFastener
We manufacture roofing screws with points and threads matched to the steel thicknesses common in your market, test every batch for drill performance, torsional strength and salt-spray resistance, and support each shipment with full mill certificates and test reports - so the screw you install is the screw you specified.
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