How and where to use guide
VELUX Twin and Combination Flashings 78x98cm EKJ MK04 S0021E
Typical applications and compatibility
This twin and combination flashing is engineered specifically for compatible VELUX roof window and Sun Tunnel systems. It works with standard roof tile profiles and is designed for pitched roofs in both new build and refurbishment scenarios. The coupled recessed design means the flashing integrates directly with the window frame to create a unified, weather-resistant installation. Confirm your VELUX window model is compatible with the MK04 flashing size before ordering.
- VELUX roof windows and Sun Tunnel systems only
- Standard pitched tile roofs
- New build and refurbishment projects
- 780 x 980mm aperture size
- 90mm recess depth for tile integration
Installation and site preparation
Proper preparation of the roof opening is essential for a weather-tight result. The roof opening must be cut to the correct dimensions to accommodate the 780 x 980mm flashing and 90mm recess depth. The flashing should be positioned so that it sits flush with the roof plane and integrates neatly with the surrounding tile courses. Follow VELUX installation guidance specific to your window model, as coupling and fixing methods vary. Ensure the roof structure is sound and the opening is square before fitting the flashing.
- Cut roof opening to 780 x 980mm with 90mm recess for tile integration
- Check roof structure is sound and opening is square
- Position flashing to sit flush with roof plane
- Integrate with surrounding tile courses for neat finish
- Follow VELUX-specific installation instructions for your window model
Weather-tightness and maintenance
The coupled recessed design creates a weather-tight seal when installed correctly. The flashing directs water away from the window frame and into the roof drainage system. After installation, inspect the seal between the flashing and tiles to ensure no gaps remain. In service, keep the roof clear of debris and moss growth around the flashing edges to maintain water run-off. Check periodically that the flashing remains secure and that no movement or gaps have developed, particularly after severe weather.
- Inspect seal between flashing and tiles after installation
- Keep roof area around flashing clear of debris and moss
- Ensure water drains freely from flashing edges
- Check flashing security and condition after severe weather
- Do not attempt to force or adjust flashing once fitted
Limitations and on-site considerations
This flashing is designed for standard roof tile profiles and pitched roofs only. It is not suitable for flat roofs, slate roofs, or non-standard tile types without specialist advice. The 90mm recess depth is fixed and cannot be adjusted on site. The flashing must be used as part of a complete VELUX window installation system; it cannot be used as a standalone product. Ensure adequate ventilation and insulation are installed around the window frame to prevent condensation and thermal bridging.
- Standard tile profiles only; not suitable for slate or flat roofs
- Recess depth is fixed at 90mm and cannot be adjusted
- Must be used with compatible VELUX window systems
- Ensure proper ventilation and insulation around frame
- Do not use as standalone flashing without window installation