Heavy Section Tek Screws with EPDM Washers

Heavy section self-drilling screws for fixing steel to steel without the need to pre-drill a pilot hole. Designed for use with thicker steel sections, these 5.5mm Tek-type screws drill, form their own thread and secure the fixture in a single operation.

Each screw has a hexagonal head for positive driver engagement and a 16mm EPDM sealing washer. The washer helps distribute the clamping force and seals around the fixing to reduce water ingress, making these screws particularly useful for metal roofing, cladding and general steelwork applications.

Available Sizes

TIMCO 5.5 × 38mm Heavy Section Tek Screw

A compact heavy section self-drilling screw for attaching sheet metal, brackets and other relatively thin fixtures to thicker steel.

• 5.5mm thread diameter
• 38mm overall length
• No. 5 self-drilling point
• 16mm EPDM washer
• Suitable for drilling into steel up to 12mm thick
• Ideal for fixing frame cramp ties
• Supplied in boxes of 100

JCP 5.5 × 80mm Heavy Section Tek Screw

A longer heavy section self-drilling screw for fixing thicker components, built-up steelwork, roofing systems and cladding assemblies to structural steel sections.

• 5.5mm thread diameter
• 80mm overall length
• No. 5 self-drilling point
• 16mm EPDM washer
• Suitable for steel sections from 4mm to 12.5mm thick
• Maximum fixture thickness of 50mm
• Bright zinc-plated finish
• High-clamping hexagonal head

The longer 80mm screw provides the additional reach required where insulation, spacing components or thicker steel fixtures are positioned between the screw head and supporting steel section.

Features

• Heavy section self-drilling screws for steel-to-steel fixing
• Commonly referred to as heavy section Tek screws
• Drills and forms its own thread in one operation
• No separate pilot hole required within the approved steel-thickness range
• No. 5 drill point for thicker steel sections
• Hexagonal head for secure installation
• Supplied with a bonded 16mm EPDM washer
• Washer helps prevent water ingress around the fixing
• High clamping action
• Faster installation than conventional drilling and bolting
• Available in short and long fixing lengths
• Suitable for steel sections up to 12mm or 12.5mm thick, depending on the selected product

Typical Applications

Heavy section Tek screws are commonly used for:

• Fixing steel to structural steel sections
• Metal roofing and cladding
• Flashings and trim
• Steel brackets and clips
• Secondary steelwork
• Sheet steel and metal fabrications
• Built-up roofing systems
• Steel framing components
• Industrial and agricultural buildings
• General metal-to-metal construction work

These products are designed primarily for steel-to-steel connections. A purpose-designed timber-to-steel self-drilling screw should normally be selected where timber is being fixed to a steel beam, as these commonly incorporate wings to drill a clearance hole through the timber and prevent it from jacking away from the steel.

38mm or 80mm Tek Screws?

Choose the screw length according to the thickness of the fixture being secured and the thickness of the supporting steel.

The 5.5 × 38mm TIMCO screw is suited to thinner metal fixtures where a shorter fixing is sufficient.

The 5.5 × 80mm JCP screw can accommodate fixtures up to 50mm thick while drilling into steel from 4mm to 12.5mm thick.

The screw must be long enough for the complete drill point to pass through the supporting steel and for the thread to engage correctly. Do not select the screw solely by its overall length.

What Is a Heavy Section Tek Screw?

A heavy section Tek screw is a self-drilling fastener with an extended drill point designed to penetrate thicker steel than a standard light section roofing screw.

Light section screws are generally intended for thin steel sheets. Heavy section screws use a more substantial drill point and are suitable for fixing into steel beams, columns, purlins and other thicker metal sections within the manufacturer’s specified drilling capacity.

The screw drills its own hole before the threaded section cuts or forms a mating thread in the steel. This allows the fixture to be drilled and fastened in one operation without changing between a drill bit and a separate fixing.

EPDM Sealing Washer

Both sizes are supplied with a 16mm EPDM washer.

The metal washer distributes pressure beneath the screw head, while the EPDM element compresses against the fixture to help seal the penetration and prevent water ingress.

The washer should be compressed sufficiently to form a seal but should not be crushed or excessively distorted. Over-tightening can damage the washer and reduce its ability to seal effectively.

The washer does not determine whether the complete fixing is suitable for an external or corrosive environment. The screw coating, surrounding materials and expected exposure conditions must also be considered.

Installation

Confirm that the thickness of the supporting steel is within the drilling range stated for the selected screw.

Position the fixture and create a clearance hole where required by the manufacturer or connection design.

Install the screw perpendicular to the steel using a suitable screw gun and correctly sized magnetic hex socket. Apply steady pressure while the drill point penetrates the steel.

Continue driving until the fixture is securely clamped and the EPDM washer is evenly compressed. Do not continue tightening once the washer is excessively distorted.

The drill point must pass completely through the supporting steel so that the threaded portion can engage correctly.

JCP recommends using a screw gun with a depth-sensitive nosepiece and specifically advises against high-torque tools such as impact drivers for its Metalfix screws.

Important Information

The load capacity of a self-drilling screw depends on several factors, including:

• Supporting steel thickness
• Fixture thickness
• Screw length and drill-point type
• Steel strength
• Number and spacing of screws
• Distance from steel edges
• Installation speed and technique
• Applied tensile and shear loads
• Corrosion exposure

Heavy section self-drilling screws should not automatically be treated as substitutes for structural bolts. Safety-critical or load-bearing connections should be checked against the manufacturer’s technical information and approved by a suitably qualified person.