2025.11.30 Bonded Seals / Bonded Washers for Roofing Screws

1. Product Overview

bonded Seals, commonly known asBonded Washers, are composite sealing components consisting of a metal washer permanently bonded to an elastomer sealing layer (typically EPDM).
This hybrid structure provides both mechanical load distribution and airtight, watertight sealing capability, making the product indispensable in roofing and cladding applications.

Common Specifications

• Outer Diameters: 12–30 mm (customized sizes available)

• Metal Materials: Carbon Steel, Stainless Steel 304 / 316

• Elastomer Options: EPDM (standard), Silicone (for high-temperature applications)

• Surface Treatments:

  • Zinc Plating

  • Ruspert / Dacromet

  • Hot-dip Galvanized

  • Stainless Steel Finish

• Temperature Resistance:

  • EPDM: –40°C to +120°C

  • Silicone: up to +180°C

2. Functional Features

Weather-Tight Seal

The bonded elastomer layer compresses evenly during installation, preventing water ingress, air leakage, and dust penetration—vital for roofing longevity.

Load & Vibration Absorption

The metal washer provides mechanical strength and distributes fastening forces, while the rubber layer absorbs micro-vibrations and thermal movement.

Improved Corrosion Resistance

When paired with DD Fasteners’ corrosion-resistant coatings and stainless-steel screws, the washers maintain sealing integrity even in coastal and industrial environments.

Secure Interface for Roofing Profiles

Designed to match the contours of metal roofing sheets, ensuring perfect alignment and consistent sealing performance.

3. Application Scenarios

Bonded Seals are widely used across roofing, façade, and outdoor structural projects, including:

• Metal Roofing Sheets

• Sandwich Panels

• Corrugated Panels

• Solar Bracket Installations

• Steel Structure Assemblies

• HVAC and Cladding Systems

• Agricultural & Industrial Buildings

• Energy and Infrastructure Projects

Wherever self-drilling roofing screws are used, bonded washers are an essential companion.

4. Technical Advantages

✔ Enhanced Waterproofing Longevity

EPDM material resists UV radiation, ozone degradation, and temperature fluctuations—ensuring sealing performance for 10–20 years depending on environment.

✔ High Compatibility with Roofing Screws

Optimized for Hex Washer Head Self-Drilling Screws, Self-Tapping Screws, and Farmer Screws.

✔ Strong Structural Support

Prevents panel deformation and stress cracking by distributing load over a wider surface area.

✔ Versatility Across Materials

Effective on metal, coated steel panels, polycarbonate sheets, and composite panels.

✔ Aesthetic Integration

Available in natural metal finish or color-coated options to match roofing systems.

5. Industry Use-Cases & Popular Options

Most Widely Used Combinations

• EPDM + Zinc-Plated Washer
  Standard for residential and commercial roofing.

• EPDM + Stainless Steel 304/316 Washer
  Preferred in coastal, high-humidity, and industrial zones.

• Silicone + Stainless Steel Washer
  Chosen for high-temperature environments.

Common Sectors

• Construction and Roofing Contractors

• Metal Building Manufacturers

• Solar Energy Engineering Firms

• Agricultural & Livestock Structure Builders

• Industrial Facility Installers

6. Practical Considerations & Limitations

Advantages

• Long-term sealing reliability

• High resistance to weathering

• Stable mechanical support under varying temperatures

• Easy installation, universally compatible with roofing screws

• Reduced maintenance cost over building lifecycle

Limitations

• EPDM is not suitable for extreme high-temperature environments (>120°C)

• Silicone provides better heat resistance but is costlier

• Inferior coatings may shorten corrosion-resistance lifespan

DD Fasteners helps customers choose the ideal specification based on their environmental and structural requirements.

7. Why Choose DD Fasteners?

• 6000+ tons monthly production capacity ensures steady global supply

• Strict material testing for rubber elasticity, sealing fatigue, and metal hardness

• Multi-stage quality inspection for bonding integrity and dimensional accuracy

• Customizable specifications for OEM/ODM clients

• Exporting to over 120 countries, trusted by construction and roofing industries worldwide