Roofing Screws Guide – Sizes, Types & Applications

Choosing the correct roofing screws is essential for achieving a secure, weatherproof and long-lasting fixing. This guide explains the differences between common sizes, types and applications of roofing screws used for metal sheets, cladding and sandwich panels.

What Are Roofing Screws?

Roofing screws are self drilling fasteners designed for fixing metal sheets, cladding panels and roofing materials to steel or timber structures. They are typically supplied with a hex head and a bonded EPDM washer to create a watertight seal.

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Common Types of Roofing Screws

Self Drilling Tek Screws

Tek screws feature a drilling tip that allows installation without pre-drilling. They are commonly used for metal-to-metal and metal-to-timber fixing.

• 4.8mm Tek Screws – for light sheet metal and general fixing
• 5.5mm Tek Screws – for stronger fixing and thicker materials
• 6.3mm Tek Screws – for heavy-duty applications

Sandwich Panel Screws

These screws are designed for fixing insulated sandwich panels to steel structures. They often feature extended lengths and high corrosion resistance coatings.

See our full range of sandwich panel screws.

Choosing the Right Screw Size

The correct screw length depends on the thickness of the material being fixed and the required penetration into the base structure.

• Short screws (16–25mm) – ideal for thin sheet metal
• Medium screws (32–50mm) – suitable for standard roofing and cladding
• Long screws (60mm+) – used for thicker panels and timber structures

Why EPDM Washers Are Important

EPDM washers provide a watertight seal between the screw and the surface. They prevent water ingress and protect against weather damage, making them essential for roofing applications.

Corrosion Resistance (C4 & C5)

Roofing screws are often rated for corrosion resistance:

• C4 – suitable for industrial and coastal environments
• C5 – suitable for highly aggressive environments such as marine areas

Common Applications

• Roofing sheets and metal cladding
• Garages, sheds and workshops
• Industrial buildings and warehouses
• Fixing metal panels to timber or steel structures

Quick Tips

• Always match screw length to material thickness
• Do not overtighten – it can damage the washer
• Use the correct hex driver size
• Ensure proper alignment for a secure seal

Explore our full range of roofing screws and fixings to find the right solution for your project.