How and where to use guide
EDLS FFKF06 2000 VELUX Slate flashing, Pro+ with BDX 2000, 3 in 1, grey, 188mm x 118mm
Suitable applications and roof types
This flashing is designed exclusively for slate tile roofing applications where slate thickness does not exceed 8mm. It is the correct choice when installing VELUX roof windows into pitched slate roofs as part of new builds or renovation projects. The integrated design makes it particularly suitable for situations where space is limited or where reducing the number of separate components on site is beneficial. The grey finish works well with most slate roof colours, though you should verify colour compatibility with your specific slate tiles before ordering.
- Slate tile roofing only, maximum 8mm thickness
- Standard VELUX roof window openings at 188mm × 118mm
- New installations and roof renovations
- Pitched roof applications
Installation and on-site handling
Before installation, ensure the roof opening is prepared to the correct dimensions and that the slate tiles around the opening are cut cleanly to size. Position the 3-in-1 flashing unit over the roof opening, ensuring the integrated BDX 2000 insulation collar sits properly around the window frame and the underfelt collar (BFX) is correctly positioned to direct water towards the roof surface. The integrated design means you do not need to separately install an insulation collar or underfelt collar, reducing handling and assembly steps on site. Secure the flashing according to VELUX installation instructions, ensuring all edges are sealed and the flashing sits flush with the slate surface.
- Verify roof opening dimensions match 188mm × 118mm specification
- Check slate thickness does not exceed 8mm before ordering
- Position flashing with BDX 2000 collar centred on window frame
- Ensure underfelt collar directs water flow correctly
- Seal all edges to prevent water ingress
- Follow VELUX installation guidance for securing and finishing
Thermal performance and weatherproofing
The integrated BDX 2000 insulation collar provides thermal performance around the window opening, reducing heat loss and condensation risk. The combined underfelt collar (BFX) manages water run-off and directs moisture away from the window frame and into the roof covering. The 3-in-1 design ensures these functions work together as a complete system without gaps or misalignment that could occur with separately installed components. Proper installation of the flashing is critical to maintaining both thermal efficiency and weatherproofing performance.
- BDX 2000 collar maintains thermal performance around window
- Underfelt collar (BFX) manages water drainage
- Integrated design eliminates gaps between components
- Correct installation essential for weather and thermal performance
Limitations and important considerations
This flashing is designed for slate tiles only and is not suitable for other roof coverings such as clay tiles, concrete tiles, or asphalt shingles. It is rated for slate thickness up to 8mm; thicker slate tiles require a different flashing specification. The 188mm × 118mm dimensions are fixed and suit standard VELUX roof window openings; non-standard window sizes require different flashing units. Always verify that your roof window model and opening dimensions match this specification before installation. Do not attempt to use this flashing on flat roofs or low-pitch applications where it is not designed to function.
- Slate tile roofing only; not for clay, concrete, or asphalt tiles
- Maximum slate thickness 8mm; thicker tiles need alternative flashing
- Fixed dimensions 188mm × 118mm for standard VELUX windows only
- Not suitable for flat roofs or low-pitch installations