How and where to use guide
VELUX Twin and Combination Flashings 55x98cm EKL CK04 0021E
Typical applications and installation locations
Use this flashing when installing multiple CK04 roof windows vertically aligned or side-by-side on pitched roofs. It is suitable for both new roof construction and retrofit installations where tile or slate coverings are specified. The flashing integrates the weatherproofing between adjacent windows, eliminating the need for separate individual flashings in twin or combination layouts. This product is ideal for loft conversions, attic rooms, or any pitched roof project requiring coordinated multi-window ventilation or daylighting.
- Pitched roof installations with tile or slate coverings
- Twin window configurations on the same roof plane
- Combination layouts mixing different window types
- Loft conversions and attic room projects
- New builds and retrofit applications
Installation and positioning
Position the flashing to align with the CK04 window dimensions (55x98cm) before fixing to the roof structure. Ensure the flashing sits correctly between the roof covering and window frame, with adequate overlap on all sides to direct water away from the window perimeter. Follow VELUX installation instructions to secure the flashing and seal all joints. The combination design accommodates flexible positioning for twin or mixed-type window arrangements on the same roof slope.
- Align flashing with CK04 window opening dimensions
- Position before laying roof tiles or slates
- Ensure adequate overlap for water run-off
- Seal all joints according to manufacturer guidance
- Check alignment for twin or combination layouts before final fixing
Compatibility and limitations
This flashing is engineered specifically for CK04 window sizes and pitched roofs with tile or slate coverings. It is not suitable for flat roofs, metal sheet roofing, or windows of different sizes. The combination design supports flexible multi-window configurations but requires correct alignment during installation to maintain watertight performance. Do not use with incompatible window sizes or roof covering types, as this will compromise weatherproofing and thermal integrity.
- CK04 window size only
- Pitched roof tile and slate coverings only
- Not suitable for flat roofs or metal sheet roofing
- Requires correct alignment for twin or combination layouts
- Do not force or modify the flashing to fit non-standard applications
On-site handling and maintenance
Store the flashing flat and protected from weather before installation. Inspect for damage or deformation before fitting. Once installed, the flashing requires no routine maintenance beyond ensuring roof tiles or slates remain secure and clear of debris around the window perimeter. Check that water drains freely away from the flashing edges, particularly after heavy rain or snow melt. If gaps or movement are noticed around the window frame, reseal joints promptly to prevent water ingress.
- Store flat and protected from weather until installation
- Inspect for damage before fitting
- Keep roof tiles and slates secure around flashing edges
- Clear debris from flashing perimeter regularly
- Reseal any gaps or joints that show movement or wear