CWL Under-Membrane Mounting Plate with 50 mm Screw and EPDM Washer

Roofers and solar installers working on flat or low-slope roofs need a secure anchoring point that won't compromise the waterproofing layer. This CWL mounting plate is installed beneath the roofing membrane or tar paper, providing a reliable fastening base for solar panel brackets, antennas, vents, and other roof-mounted equipment. The kit includes a galvanized steel plate, a 50 mm self-tapping screw, and an EPDM rubber washer that together create a watertight seal once the membrane is applied over the plate.

Key specifications

• Plate dimensions: 100 x 100 mm, thickness approx. 1.5 mm
• Material: galvanized steel for high corrosion resistance
• Screw length: 50 mm, self-tapping for wood or metal substructures
• Washer material: EPDM rubber, UV and weather resistant
• Compatible with bituminous membranes, EPDM, PVC, and TPO roofing systems
• Part of the CWL system for integrated roof mounting

Why choose it

The galvanized steel plate offers long-term durability even in harsh weather, while the EPDM washer ensures a flexible, watertight seal that prevents leaks around the penetration point. Because the plate sits under the membrane, the roof remains smooth and free of exposed fasteners, reducing the risk of water pooling or damage. Installation is straightforward: place the plate on the substructure, drive the screw through the center, and then lay the membrane over it, allowing the washer to compress and seal.

Ideal use cases

• Securing solar panel mounting rails on flat roofs
• Anchoring antennas, satellite dishes, and vents
• Fastening HVAC units or other roof-mounted equipment
• Creating a stable base for walkways or safety systems

Good to know

The plate is designed for use with the CWL system, ensuring compatibility with a range of accessories. The EPDM washer remains flexible over time, accommodating thermal expansion and contraction without losing its sealing properties. This mounting plate is a reliable choice for both new installations and retrofits where roof integrity is paramount.