Fixing and buying guide
VELUX Twin and Combination Flashings 55x98cm EKL CK04 0021E
Who this product is for
This flashing is essential for builders, roofers, and serious DIY installers planning multiple roof window installations on pitched roofs. It suits projects where space or design requires two or more windows on a single roof plane, whether you are installing matching twin windows or combining different VELUX window types in the same layout.
Compatibility and sizing
This flashing is designed exclusively for CK04 window dimensions (55x98cm). Before ordering, confirm that all windows in your installation are CK04 size. The flashing is compatible with pitched roofs covered in standard clay or concrete tiles and natural or synthetic slate. Check your roof covering type and pitch angle against VELUX installation guidance to ensure suitability.
- Window size: CK04 only
- Flashing dimensions: 55x98cm
- Roof coverings: Tile and slate
- Pitched roof installations only
What is included and pre-install checks
Verify the product code EKLCK040021E matches your order. Inspect the flashing for damage before installation. Confirm all CK04 windows are to hand and that your roof structure, covering, and pitch are suitable for this flashing type. Check that you have adequate access and working space around the installation area, and review VELUX installation instructions specific to twin and combination configurations.
- Check product code EKLCK040021E on delivery
- Inspect flashing for transport damage
- Confirm all windows are CK04 size
- Verify roof covering and pitch compatibility
- Review VELUX twin window installation guidance
Installation and performance
Proper installation is critical for watertight performance and thermal integrity. The combination design allows flexible positioning of windows within the flashing footprint, but each window must be fully supported and sealed according to VELUX instructions. Ensure all weatherproofing seals are complete around window perimeters and that the flashing integrates correctly with your tile or slate covering. Poor installation can compromise water resistance and energy efficiency.