High-Performance Sealing Solutions for Modern Architecture
Fasto hex washer head self-drilling screws with bonded EPDM washers are a versatile, weather-resistant fastening solution specifically engineered for metal roofing, side cladding, and structural steel assemblies. Each screw integrates the rapid-penetration capabilities of a self-drilling point with the sealing security of a factory-bonded EPDM washer, delivering a watertight, corrosion-protected connection in a single installation pass.
Designed to meet the stringent requirements of standard DIN 7504K, these fasteners are the primary choice for contractors, structural engineers, and industrial builders seeking to eliminate moisture intrusion and structural degradation in harsh outdoor environments.
DIN 7504K Certified
Manufactured to strict European standards ensuring consistent steel hardness, thread pitch accuracy, and EPDM vulcanization performance.
Core Value & Selling Points
Why industry professionals trust our EPDM washer self-drilling screws for critical building envelopes.
Watertight EPDM Seal
The factory-bonded EPDM washer compresses uniformly under torque, sealing out rain, snow, dust, and atmospheric moisture. Prevents capillary leaks around the shank.
Rapid Self-Drilling Point
Engineered point drills, taps, and fastens in one continuous operation. Eliminates the need for pre-drilling, reducing on-site labor times by up to 50%.
Advanced Corrosion Defense
Available in premium zinc plating, hot-dip galvanized (H.D.G.), and A2/A4 stainless steel configurations to withstand aggressive industrial and marine climates.
High-Torque Hex Drive
The hex washer head design ensures max engagement with driving sockets. Prevents slippage, cam-out, and driver wear, ensuring clean installation alignment.
Multi-Substrate Fastening
A truly universal fastener optimized for securing metal sheets to both cold-rolled steel purlins and heavy-duty timber structural framing components.
UV & Ozone Resistance
Formulated with high-grade synthetic EPDM rubber. Resists thermal cracking, ozone damage, and intense UV degradation, maintaining structural elasticity for decades.
Detailed Material Science & Process
Understanding the engineering behind our high-durability roofing fasteners.
EPDM vs. Standard Neoprene
Unlike basic neoprene washers which degrade and crack within 3-5 years of direct sunlight exposure, our EPDM (Ethylene Propylene Diene Monomer) compounds are chemically synthesized to resist ozone cracking, thermal degradation, and acid rain, maintaining elastomeric tension from -40°C to +120°C.
Material Composition & Structural Grades
Our roofing screws are manufactured from cold-heading quality carbon steel, premium alloy steel, or high-grade stainless steel (SUS 304/316). We supply screws in multiple strength classes to match structural loading designs:
- Class 4.8 / 8.8 / 10.9: High-tensile carbon steel, heat-treated for optimal surface hardness to pierce thick steel purlins without tip burning.
- A2-70 / A4-70 (Stainless Steel): Ideal for maritime, coastal, or chemical processing plants where atmospheric salt or acid levels are exceptionally high.
The Bonded Washer Mechanics
The washer is not simply loose rubber. It is a composite consisting of a metal backing washer (galvanized steel or stainless steel) vulcanized and heat-bonded to the EPDM rubber seal. This dual-layer structure ensures that as the hex head is tightened, the metal backing distributes the clamping pressure evenly across the EPDM sheet, preventing the rubber from splitting, tearing, or squeezing outward.
Technical Specifications
Comprehensive dimensional and physical parameters for DIN 7504K self-drilling screws.
| Parameter | Specification Details |
|---|---|
| Size Range | M4.2 (#8), M4.8 (#10), M5.5 (#12), M6.3 (#14) |
| Length Range | 19 mm – 150 mm (Custom lengths available on request) |
| Head Design | Hex washer head / Hex flange head for maximized socket contact |
| Thread Configuration | Full thread / Partial thread (optimized for structural clearance) |
| Drive Style | Hexagonal or slotted drive configurations |
| Drill Point Style | Self-drilling point – drills, taps, and fastens in one operation |
| Washer Assembly | Bonded EPDM sealing washer (metal backing + vulcanized EPDM rubber) |
| Washer Dimensions | 1/4" × 5/8" standard sizing; M4 – M10 sizes custom-engineered per drawing |
| Materials Available | Carbon steel, stainless steel (SUS 304, SUS 316), alloy steel |
| Mechanical Grades | Class 4.8 / 8.8 / 10.9; A2-70 / A4-70 (stainless grades) |
| Manufacturing Standard | DIN 7504K (screw body); DIN standards for washer backing |
| Surface Finishes | Plain finish, bright zinc plated (Cr3+ / Cr6+), hot-dip galvanized (H.D.G.) |
| Salt Spray Resistance | Tested per ASTM B117; hours vary by finish (consult engineering team) |
| EPDM Temperature Limits | -40 °C to +120 °C (typical service range for industrial EPDM compound) |
Installation Mechanics & Application Guidelines
Achieving a reliable, leak-proof seal requires correct installation torque and speed. When installing self-drilling screws with EPDM washers, it is essential to monitor the compression level of the rubber. Over-tightening will cause the EPDM to squeeze out and degrade prematurely under UV light, while under-tightening will fail to compress the rubber enough to block water ingress.
Correct Compression Indicators:
- Under-driven: The EPDM rubber is loose or barely touching the metal sheet. Water can easily bypass the threads.
- Correctly driven: The EPDM washer is visibly compressed, with its edge slightly visible beyond the metal backing perimeter. The seal is completely flat and tight.
- Over-driven: The EPDM rubber is forced outward, bulging or splitting around the metal backing. This damages the rubber's molecular structure and breaks the seal.
Primary Applications:
These fasteners are widely deployed across residential, commercial, and heavy industrial steel structures, including:
Installation Best Practices
Logistics, Packaging & Supply Chain
Reliable global delivery structures designed for bulk industrial distributors and major construction projects.
| Logistics & Supply Terms | |
|---|---|
| Packaging Options | Small box packaging, bulk carton packing, heavy-duty wooden pallets, or customized OEM retail packaging layouts. |
| Minimum Order (MOQ) | 10,000 pieces (negotiable based on size and finish specifications). |
| Sample Policy | Free samples available; shipping freight paid by buyer (refunded upon official contract placement). |
| Lead Times | Standard catalog products: 4–7 working days; General bulk orders: 15–30 days; Custom production orders: 30–45 days post-deposit. |
| Payment Framework | T/T (30% down payment, 70% balance due prior to shipment). |
| Origin | Tianjin, China – Fasto Industrial Co., Ltd. shipping hub. |
Global Distribution Capabilities
At Fasto Industrial, we recognize that project timelines are critical. Our logistics team coordinates with premier shipping lines and air freight forwarders to guarantee on-time delivery across Europe, the Americas, the Middle East, and Southeast Asia.
All bulk shipments are packed in moisture-resistant cartons and reinforced with heavy-duty plastic strapping on export-grade wooden pallets. This packaging integrity prevents damage during maritime transit and simplified warehousing upon arrival.
Technical Buyer Checklist (Data to Confirm):
- Salt spray resistance hours (ASTM B117)
- EPDM washer hardness (Shore A)
- Exact EPDM thickness requirements
- Dimensional drawings with tolerances
- ISO 9001:2015 certificate requests
- Custom carton label designs
About Fasto Industrial Co., Ltd.
A trusted manufacturing partner delivering high-integrity fastener systems worldwide since 2005.
20+ Years Experience
Manufacturing and exporting industrial fasteners to over 50 countries since 2005.
Factory-Direct Pricing
In-house production lines ensure competitive pricing without middleman markups.
OEM / ODM Support
Full customization of head designs, thread pitches, and washer compositions.
Certified Quality
ISO 9001:2015 and IATF16949 quality management systems certified.
Frequently Asked Questions
Get technical answers to common queries regarding our roofing screws with EPDM washers.