How and where to use guide
VELUX Twin and Combination Flashings 55x78cm EBL CK02 0021C
Suitable applications and roof types
This flashing is specifically engineered for slate roof installations only. It is suitable for both new build construction and refurbishment work where VELUX roof windows or Sun Tunnel systems are being installed. The flashing accommodates a 50mm gap between the roof window frame and the slate surface, which is the critical specification for correct installation. Use this flashing only with compatible VELUX roof window and Sun Tunnel systems as part of a complete daylight and ventilation solution.
- Slate roofs only
- New build and refurbishment projects
- VELUX roof windows and Sun Tunnel systems
- 50mm gap specification essential for correct fit
Installation and positioning
The flashing must be positioned to bridge the 50mm gap between your roof window or Sun Tunnel frame and the slate roof surface. The 550 x 780mm dimensions are designed for standard roof window openings. Ensure the flashing sits flush against both the window frame and the slate surface to create an effective weather-tight seal. The flashing should be installed before the roof window is fully secured, allowing it to integrate neatly with the slate surface. Proper positioning is critical to prevent water penetration and ensure long-term performance.
- Position to bridge the 50mm gap between window frame and slate
- Ensure flush contact with both window frame and roof surface
- Install before final window securing
- Check dimensions match your roof window opening
Weather-tightness and roof finish
This combination flashing is engineered to deliver a weather-tight seal, which is essential for protecting your roof structure and interior spaces from water ingress. The professional finish integrates neatly with the slate roof surface, maintaining visual consistency and the appearance of your roof. The flashing works as part of the complete VELUX system to ensure reliable performance in UK roof conditions, including exposure to rain, wind, and temperature variations. A properly installed flashing prevents water pooling and directs moisture away from the window frame.
- Delivers weather-tight seal around window frame
- Prevents water ingress and pooling
- Maintains neat, professional roof appearance
- Engineered for long-term UK weather exposure
Maintenance and on-site tips
After installation, inspect the flashing regularly to ensure it remains in good condition and that the seal around the window frame has not been compromised. Clear any debris such as slate dust or leaves that may accumulate around the flashing edges. Check that water drains freely away from the window frame and does not pool on the flashing surface. If you notice any gaps, movement, or signs of water ingress around the window, inspect the flashing immediately and reseal if necessary. Keep the flashing clean to maintain its effectiveness and visual appearance.
- Inspect regularly for gaps or movement
- Clear debris from flashing edges
- Ensure water drains freely away from window frame
- Reseal if gaps or water ingress appear