Hex Washer Head Self-Drilling Screw with EPDM Washer
Roofing and cladding screw with a bonded EPDM sealing washer and #2 or #3 drill point.
Every fixing through a metal roof is a deliberate hole in the weather envelope, so this screw has to be two things at once: a fastener and a seal. The bonded EPDM washer under the hexagon flange compresses against the sheet as the screw seats and closes the penetration.
Underneath, the drill point does the structural half of the job. A #2 point suits thinner purlins and girts; a #3 point carries through heavier structural steel. Getting that choice right is what stops installers burning points out halfway through a roof.
Why buyers choose it
- Bonded EPDM washer seals the penetration as the head seats
- #2 and #3 drill points cover thin gauge through to structural steel
- Hexagon head drives with a socket, so no recess to strip on a roof
- Ruspert and other coating options for coastal and severe exposure
Send the total steel thickness the point has to pass through, the head style and the exposure and the size will be confirmed against the closest standard before quoting. Samples of this item are free of charge.
Specification
| Standard | ASME B18.6.4 & SAE J78 DIN7504K, DIN7504P, DIN7504N |
|---|---|
| Size | #4(2.8)-1/2″ |
| Length | 10-180mm (3/8”- 7”) |
| Material | C1022+ heat treatment |
| Head Type | hex, flat, pan, truss, round, hex washer, Oval, pan framing, bugle, fillister |
| Drive Type | Phil, slotted, Phil & slotted combination, hex socket |
| Drill Point | #2, #3 |
| Screw Type | BSD, CSD |
| Finish | zinc plated(clear/blue/yellow), black/grey phosphate, nickel, Ruspert |
Specification as published by Haiyan Ehons Industrial Co., Ltd.. Drill capacity is set by the point supplied; state the total steel thickness on the enquiry.
Technical detail
| Standards | ASME B18.6.4, SAE J78, DIN 7504K, DIN 7504P and DIN 7504N. |
|---|---|
| Size | #4 (2.8) to 1/2 in, length 10 to 180 mm (3/8 in to 7 in). |
| Drill point | #2 and #3. |
| Material | C1022 with heat treatment. |
| Finish | Zinc plated in clear, blue or yellow, black or grey phosphate, nickel and Ruspert. |
Problems this screw solves
Every fixing is a potential leak
The bonded EPDM washer is the seal. It has to compress evenly, which is a function of head geometry and of not over-driving.
Points burn out in heavy purlins
Matching point size to the total steel thickness is the fix. State the thickness rather than ordering by screw length.
Rust streaks appear under every screw
Coating choice is the whole answer. Ruspert and the higher plating specifications exist for exactly this.
Where it is used
- Fixing profiled metal roof sheeting to purlins
- Wall cladding and rainscreen panel fixing to girts
- Flashing, ridge and barge capping fixings
- Agricultural and industrial building envelopes
Who buys it
Roofing and cladding contractors, metal building suppliers and distributors serving industrial and agricultural construction.
Quality control priorities
Washer bonding is the check that is unique to this part: samples are pulled to confirm the EPDM is bonded to the steel washer rather than merely assembled, and the washer is inspected for concentricity with the head. Drill point hardness and flute form are checked after heat treatment on each batch.
Customisation
Washer diameter, point size and coating all move with the application. For coastal projects specify Ruspert at enquiry stage rather than after the first order, since it is a separate process route and affects lead time.
How it compares
Against a plain hex washer head screw
Without the EPDM washer the screw is a fastener but not a seal. Use the plain version only where the fixing is not through a weather surface.
Against a truss head drill-point screw
The truss head has a wide crown but no sealing capability and no socket drive.
Against a self-tapping hex washer screw
This listing is supplied as a drill-point screw; the old site also describes it as a self-tapping hex washer head screw with EPDM washer. Confirm which point you need on the enquiry.
Installation notes
Set the depth stop
Over-driving extrudes the EPDM washer and destroys the seal. Use a depth-sensitive nose or a clutch.
Match the point to the steel thickness
#2 for thinner purlins, #3 for heavier structural steel. Give the thickness when ordering.
Fix in the pan or the crown as the sheet demands
Follow the sheet manufacturer's guidance; the screw length changes with it.
Do not re-use a withdrawn screw
Once the washer has been compressed it will not seal again.
Frequently asked questions
What does the EPDM washer do?
What drill points are available?
What sizes and lengths?
Which coating suits a coastal site?
What standards does it follow?
What is the minimum order?
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Minimum order 500 kg for this item.