Roofing and cladding screws
Self-drilling hex/washer head screws with EPDM sealing gasket for watertight fixing of metal roofing sheets, cladding panels and flashings to timber or light-gauge steel purlins. The integrated EPDM washer compresses to form a watertight seal at the fixing point — critical for maintaining a weatherproof roof.
How to choose the right roofing screw
Our TechFast 5.5 x 25mm hex/washer screw is designed for fixing metal roofing sheets to timber purlins. For thicker materials or steel purlins, longer screws may be required. Check the combined thickness of roofing sheet plus purlin to determine the right length. Always use a magnetic hex bit and drive until the EPDM washer is compressed but not crushed — overtightening damages the seal.
Trade Tip
Trade tip: Always pre-drill a pilot hole before fixing roofing and cladding screws. This prevents panel splitting, ensures a flush finish, and avoids over-driving. Use the correct torque setting — over-tightening breaks the weatherproof seal.
Frequently Asked Questions
What is the EPDM washer for?
The EPDM rubber washer sits under the hex head. When driven, it compresses against the roofing sheet to form a watertight seal, preventing rain entering through the screw hole.
What size roofing screw do I need?
5.5 x 25mm for standard metal roofing to timber purlins. For thicker materials or steel purlins, longer screws up to 100mm may be required. Check combined thickness of sheet plus purlin.
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TechFast Roof Screw Hex/Washer (5.5x25mm) - Box of 100, 10, or 50
Regular price From £4.20 GBPRegular price
