STAINLESS STEEL HEXAGON HEAD BI-METAL COMPOSITE PANEL TEK 3 SCREWS WITH SEALING WASHER

Hexagon Head Bi-Metal Composite Panel Tek 3 Screws with Sealing Washer — Composite panels are pre-insulated wall and roof panels with a metal skin on each face bonded around a rigid insulation core, widely used in industrial units, cold stores, and food-production buildings, and fixing through one is a different job to fixing through a single sheet - the screw has to pass cleanly through the outer facing, the full insulation core, and the inner facing before the Tek 3 point even reaches the supporting steel structure beneath. Length and washer sizing on this screw are matched specifically to that build-up, so the screw clears the panel core without crushing or compressing the insulation as it's driven, rather than being sized the way a standard single-skin roofing screw would be. The sealing washer closes the fixing point against moisture at the outer face, which matters as much on a composite panel as on any external cladding connection. Construction follows the same bi-metal principle as the rest of the Tek range: a stainless body and thread give the fixing long-term corrosion resistance suited to the panel's external exposure, while a hardened carbon-steel point brazed to the tip self-drills into the medium-gauge steel structure supporting the panel - a plain stainless point isn't hard enough to do that reliably. Tek 3 point rating is matched to the steel purlins, rails, or structural sections typically found behind a composite panel installation; where the supporting steelwork is heavier, the Tek 5 composite panel version with its larger 16mm washer is the correct step up rather than pushing a Tek 3 point beyond its capacity. Beyond point rating, the key sizing decision is length matched to the specific panel thickness in use, since composite panels come in a range of core thicknesses and an incorrectly short or long screw either fails to reach solid steel or bottoms out against it before the panel is fully clamped.

FAQs
Can a standard Tek 3 washered screw be used on a composite panel instead of this dedicated version?
It's not recommended - the standard screw isn't sized for the panel's insulation core thickness, so it risks crushing the core, leaving thread exposed, or failing to reach solid steel; the dedicated composite panel screw is length-matched to the panel build-up.

How is panel core thickness accounted for when specifying length?
Length is selected to pass through the outer facing, the full insulation core, and the inner facing without compressing the core, so it should always be checked against the specific panel thickness in use on the project rather than assumed standard.

How does this compare with the Composite Panel Tek 5 version?
Both are designed for composite panel fixing, but the Tek 5 version has greater drilling capacity for thicker steel structure and uses a 16mm washer, rather than the standard sealing washer fitted to this Tek 3 version.