DIYUK Hex Head Self-Drilling Tek Roofing Screws, EPDM Rubber Washer, Zinc Plated, 4.8mm x 20mm 35mm 50mm, Metal Roof and Cladding, Packs of 10-1000

DIYUK hex head self-drilling Tek roofing screws with a bonded EPDM rubber sealing washer, in 4.8mm x 20mm, 35mm and 50mm lengths and packs of 10, 25, 50, 100, 200, 500 or 1000. These self-tapping roofing screws drill their own hole and secure the sheet in one step, which speeds up installation and saves time and labour on site.

Hex head self-drilling Tek screws fitted with an integral, bonded EPDM sealing washer. Designed for fixing thin steel sheeting – such as trapezoidal or box-profile roofing and cladding panels – to steel purlins or timber structures, the hardened drill point pierces, taps and fastens the material in a single pass, removing the need for a separate pilot hole. The bonded EPDM washer forms a weatherproof seal around the fixing point and allows a small degree of thermal movement between the sheet and the washer face, helping the seal stay intact as the roof or cladding expands and contracts with temperature.

Each screw has a 4.8mm (0.19in, commonly known as a No. 10 gauge) fully threaded shank for consistent pull-out resistance along its full length, and a hexagonal washer head with an 8mm (5/16in) across-flats drive, suited to a standard nut-setter on a torque-adjustable screwdriver. The screw and the metal component beneath the EPDM washer are zinc plated for corrosion protection. The range is offered in three lengths – 20mm, 35mm and 50mm (0.79in, 1.38in and 1.97in) – to suit a range of sheet and purlin thicknesses, from thin single-skin cladding through to thicker composite panel builds.

The head and point are made to the DIN 7504-K profile, the recognised pattern for hex-washer-head self-drilling screws, so the drilling and thread-forming action is consistent from box to box. The screw is CE marked under a European Technical Assessment. The torque value should be determined experimentally before installation, so the EPDM washer seats and seals correctly without being crushed or under-driven.

Made from hardened steel, the screw is durable and resistant to corrosion for long-lasting fastening, and the three lengths let you match the screw to the build.

Key Features

• Self-drilling point: pierces, taps and fastens thin steel sheet in one pass, with no pre-drilling required in typical roofing/cladding gauges.
• DIN 7504-K profile: the recognised head/point pattern for hex-washer-head self-drilling screws, for a consistent drill-and-thread action.
• Bonded EPDM washer: forms a weatherproof seal around every fixing point and accommodates a small amount of thermal movement without losing its seal.
• Hex washer head: 8mm across-flats drive suits a standard nut-setter on a torque-adjustable screwdriver for fast, consistent driving.
• Zinc-plated finish: corrosion protection on both the screw and the metal component beneath the washer.
• Full-length thread: gives consistent pull-out resistance along the whole shank rather than just the tip.
• CE marked: under a European Technical Assessment.
• Three lengths in stock: 4.8mm x 20mm, 35mm and 50mm (0.79in, 1.38in and 1.97in), covering a range of sheet-to-purlin/timber thickness combinations.
• Quick installation: drills a hole and secures the material in one step, saving time and labour on site.
• Hardened steel: durable and resistant to corrosion, for long-lasting fastening.
• Waterproof seal: the bonded EPDM rubber washer keeps rain out and helps prevent leaks at every fixing point.
• 14mm sealing washer with a steel top: an EPDM sealing ring under a coated steel top, at least 14mm across.
• Zinc plated to a minimum of 8 microns: the carbon steel screw is quenched, tempered and zinc plated.
• Reaction to fire Class A1: classified to EN 13501-1.

Specification

Typical Applications

The 4.8mm shank and self-drilling point put this screw squarely in the roofing and cladding fixing category, while the bonded EPDM washer makes it suited to any thin-steel fixing job that needs to stay weathertight. The three stock lengths broadly track increasing sheet and purlin thickness, so the right length can be matched to the build without over- or under-driving the screw.

• Roofing and cladding: trapezoidal and box-profile steel roof sheets, corrugated cladding panels, and composite roof/wall panels.
• Steel purlin and rail fixing: fastening sheeting directly to Z, C or sigma purlins and rails in agricultural, industrial and commercial steel buildings.
• Ventilation and extraction enclosures: fixing thin-gauge steel panels on ducting, plant enclosures and roof-mounted equipment housings.
• General light-to-medium-gauge steel and timber construction: outbuildings, garages, carports, animal housing and similar steel-frame structures.
• Length selection: the 20mm length suits thin, single-skin sheet fixed to light-gauge purlins or rails; the 35mm and 50mm lengths give the extra reach needed for thicker composite panel builds, or wherever the screw has to pass through more material before it reaches the structure behind.
• Roofing enclosures: installing and maintaining roof fans and smoke extraction systems.
• Timber structures: fixing roofing sheets to wooden roof structures, and other timber constructions where secure fastening is needed.
• Metal roofing, sheet metal and steel framing: metal roof sheeting, box-profile and corrugated sheets fixed to metal roof structures and steel frames.
• Steel sheeting on steel or timber: fixing steel sheets to steel and timber supporting structures, as wall or roof cladding or as load-bearing wall and roof elements, and fixing other thin gauge metal members.

Installation Guidance

• Use a mechanical screwdriver with adjustable torque at 1,800 to 2,500 RPM, as the manufacturer specifies, so the point drills and taps cleanly.
• Trial the torque setting on an offcut first. The EPDM washer needs to be compressed enough to seal fully against the sheet, but not so much that it's crushed flat or the screw is over-driven. The torque value should be determined experimentally before installation.
• Drive the screw square to the sheet so the EPDM washer seals evenly all the way round.
• Check the seal after driving. A properly seated screw leaves the EPDM washer slightly domed and fully in contact with the sheet all the way round, with no visible gap.

Common Questions

Which length do I need?
Match the length to the build: 20mm for thin, single-skin sheet fixed to light-gauge purlins or rails; 35mm and 50mm for thicker composite panel builds, or wherever the screw passes through more material before it reaches the structure behind.

Do I need to drill a pilot hole?
No. The self-drilling point drills, taps and fixes in one pass, with no pilot hole needed in typical roofing and cladding gauges.

What do I drive them with?
An 8mm nut-setter on a mechanical screwdriver with adjustable torque, at 1,800 to 2,500 RPM as the manufacturer specifies. Trial the torque on an offcut first, so the EPDM washer seals without being crushed.

Can I fix sheets to timber?
Yes. The screws fix roofing sheets to wooden or metal roof structures, as well as to steel purlins and rails.

Can I use them as corrugated roof screws?
Yes. They fix trapezoidal and box-profile steel roof sheets, corrugated cladding panels and composite roof and wall panels.

What pack sizes are available?
Every length comes in packs of 10, 25, 50, 100, 200, 500 or 1000 screws.