Screws · Trade series (cladding fastener)

A4 (316) Stainless Steel Roofing Screws with Bonded EPDM Washer

Mechanical properties, corrosion behaviour and the full dimensional range for this grade.

A4 Stainless Steel Roofing Screws with Bonded EPDM Washer are supplied to ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80. Corrosion behaviour is superior, including marine and chloride environments, the material is largely non-magnetic, and the usable service range is approx. -200 °C to +400 °C, subject to the property class and the joint. In practice this grade is specified for marine, coastal and chemical applications.

Grade: ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Corrosion resistance: Superior, including marine and chloride environments
Magnetic response: Largely non-magnetic
Service temperature: approx. -200 °C to +400 °C, subject to the property class and the joint

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

Roofing Screws with Bonded EPDM Washer manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to Trade series (cladding fastener). The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.

Why Choose A4 Stainless Steel for Roofing Screws with Bonded EPDM Washer

Specified for marine, coastal and chemical applications. For roofing screws with bonded epdm washer, this matters when superior, including marine and chloride environments is the primary requirement.

Mechanical & Physical Properties

Grade designation	ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Magnetic response	Largely non-magnetic
Service temperature	approx. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristic	Superior, including marine and chloride environments

Corrosion Behavior in Service

A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Roofing Screws with Bonded EPDM Washer in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.

Comparable Grades

For Roofing Screws with Bonded EPDM Washer, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.

Using Stainless Fasteners in Aluminum

Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.

Sizes of Roofing Screws with Bonded EPDM Washer Available in A4 Stainless Steel

Nominal diameter (mm)	Across flats s (mm)	Washer diameter (mm)	Washer type	Drill capacity (mm)	Common length range (mm)	Material	Finish
5.5	8	16	Bonded EPDM + steel cap	1.5~5.0	19~100	Carbon steel	Ruspert / painted head
5.5	8	19	Bonded EPDM + steel cap	1.5~5.0	19~150	Carbon steel	Ruspert / painted head
6.3	8	19	Bonded EPDM + steel cap	2.0~6.0	25~150	Carbon steel	Ruspert / painted head
6.3	8	19	Bonded EPDM + A2 cap	2.0~6.0	25~150	A2 stainless head	Bi-metal, painted
6.3	10	22	Bonded EPDM + A2 cap	2.0~12.0	38~200	A2 stainless head	Bi-metal, painted

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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Specification

Item / category Standard Size(s) Material / finish Quantity

Business Information

Company * Contact Name * Email * Phone (with country code) Country / Region

Notes

Dimensions & Specifications (Trade series (cladding fastener))

Nominal diameter (mm)	Across flats s (mm)	Washer diameter (mm)	Washer type	Drill capacity (mm)	Common length range (mm)	Material	Finish
5.5	8	16	Bonded EPDM + steel cap	1.5~5.0	19~100	Carbon steel	Ruspert / painted head
5.5	8	19	Bonded EPDM + steel cap	1.5~5.0	19~150	Carbon steel	Ruspert / painted head
6.3	8	19	Bonded EPDM + steel cap	2.0~6.0	25~150	Carbon steel	Ruspert / painted head
6.3	8	19	Bonded EPDM + A2 cap	2.0~6.0	25~150	A2 stainless head	Bi-metal, painted
6.3	10	22	Bonded EPDM + A2 cap	2.0~12.0	38~200	A2 stainless head	Bi-metal, painted

Applications & Industries

What Roofing Screws with Bonded EPDM Washer are specified for, industry by industry. Stocked from 5.5 to 6.3 (screw size).

Industries that specify Roofing Screws with Bonded EPDM Washer

Metal roofing & cladding Profiled sheet fixed to steel or timber purlins.
Agricultural buildings Large-span sheeting where every fixing is a leak path.
Industrial refurbishment Over-sheeting and repair fixings.
Construction & fit-out Fixing board, batten, framing and trim into timber and light-gauge steel.
Sheet-metal & HVAC Ducting, enclosures, trunking and cladding assembled without tapped holes.
Joinery & furniture Hardware, hinges and fittings into solid timber and wood-based board.

Typical applications

fixing through the crown or the trough of a profiled sheet
bonded EPDM washer seals the hole as the screw is set
bi-metal heads where a carbon steel screw would stain the sheet
forming a thread directly in sheet, board or timber
fixing where there is no access to add a nut behind the panel
high-volume driving with a bit and a clutch-set driver

Service conditions to specify against

Marine and coastal: Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
Sealed joints: Used where the fixing has to keep water or air out as well as hold — the elastomer, not the fastener, decides service life.
Pilot hole: Selection is really a hole-size decision: too small and the screw snaps or splits the material, too large and it strips. The size is stated per row.

Where to use something else

Do not over-drive: the failure on a metal roof is almost always an extruded or UV-degraded washer, not the screw.
Not for a joint that will be dismantled and reassembled repeatedly in the same hole — use an insert or a rivet nut instead.

Full application guide: where Roofing Screws with Bonded EPDM Washer are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

01

Cold heading

Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

Head dimensions and under-head radius checked at set-up and per shift.
02

Thread rolling

Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

Go / no-go ring gauges to ISO 965 tolerance class 6g.
03

Heat treatment

Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

Core hardness and tensile tested per lot to ISO 898-1.
04

Surface treatment

Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Can A4 Stainless Steel Roofing Screws with Bonded EPDM Washer gall during installation?

Yes — stainless on stainless is prone to thread galling under load, especially at smaller sizes. Use an anti-galling lubricant or wax thread compound, and slow the tightening rate where possible.

Is A4 Stainless Steel food-grade?

A4 (316) is the standard food-contact stainless grade in most jurisdictions, particularly where chloride exposure (brines, dairy CIP) is present.

Can A4 Stainless Steel Roofing Screws with Bonded EPDM Washer be used with aluminum?

Yes, but stainless drives mild galvanic corrosion of aluminum in wet service — isolate with a coating, sleeve or paint, or accept the trade-off if the joint is dry and indoor.

What's the service temperature limit for A4 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.