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Fixing and buying guide

VELUX Twin and Combination Flashings 55x78cm EBL CK02 0021C

What this product is and who it is for

This is a combination flashing designed for roofers, builders, and experienced DIY installers working with slate roofs. It sits between a VELUX roof window or Sun Tunnel and the slate surface to prevent water ingress and create a professional finish. Use this flashing when your roof window or Sun Tunnel sits 50mm proud of the slate surface. It is suitable for both new build projects and refurbishment work on existing slate roofs.

Compatibility and sizing

This flashing is compatible with VELUX roof windows and Sun Tunnel systems only. The 550 x 780mm dimensions (55 x 78cm) are designed for standard roof window openings. Before ordering, confirm that your roof window or Sun Tunnel is a VELUX product and that the gap between the unit and slate surface is exactly 50mm. If your gap differs, you will need a different flashing specification.

  • Product code: EBL CK02 0021C
  • Flashing type: Twin and Combination
  • Roof type: Slate only
  • Gap specification: 50mm

What is included and pre-installation checks

You receive one flashing unit sized 550 x 780mm. Before installation, inspect the flashing for any damage in transit. Measure the gap between your roof window or Sun Tunnel and the slate surface to confirm it is 50mm. Check that your roof window or Sun Tunnel is a compatible VELUX model. Ensure the slate roof surface is clean and free from debris, moss, or loose material where the flashing will sit. Have all necessary roofing sealants and fixings to hand; these are not included with the flashing.

Installation and performance

This flashing must be installed by a competent roofer or experienced builder familiar with slate roof work. The flashing is engineered to create a weather-tight seal and integrate neatly with the slate surface, delivering a professional finish. Proper installation is critical to ensure long-term performance in UK roof conditions and to prevent water ingress around the roof window or Sun Tunnel. If you are unsure about installation, consult a qualified roofer or contact VELUX for guidance.