How and where to use guide
VELUX Underfelt Collar 94x160cm BFX PK10 1000
Typical applications
This underfelt collar is designed specifically for VELUX roof window and Sun Tunnel installations. It sits between the window frame and the roof structure, providing the critical weather-tight seal that prevents water ingress. Use one collar per window or Sun Tunnel installation. The product is equally suitable for new build projects where roof windows are being integrated into the design, and for refurbishment work where existing roof structures are being upgraded with daylight and ventilation solutions.
- New build roof window installations
- Refurbishment and retrofit projects
- VELUX Sun Tunnel installations
- Multiple window installations (10 units per pack)
Installation and positioning
The underfelt collar must be positioned between the roof window frame and the roof structure during installation. The integral transverse drainage gutter is engineered to direct water run-off away from the window frame, so ensure the collar is correctly oriented with the gutter functioning as designed. The 940x1600mm dimensions are standardised for VELUX compatible products, so verify your specific window model matches this specification before ordering. Install the collar as part of your complete VELUX system to ensure all components work together for optimal weather protection.
- Position collar between window frame and roof structure
- Ensure drainage gutter is correctly oriented for water management
- Verify window model compatibility before installation
- Install as part of complete VELUX system
Weather protection and maintenance
The weather-tight design of this collar is critical for long-term roof performance. The transverse drainage gutter prevents water pooling and directs moisture away from vulnerable areas around the window frame. In UK roof conditions, this design provides reliable protection against rain penetration and wind-driven moisture. After installation, periodically check that the drainage gutter remains clear of debris such as moss, leaves, or roof material fragments. Keep the collar and surrounding roof area clean to maintain optimal water shedding performance.
- Integral drainage gutter prevents water pooling
- Engineered for UK weather conditions
- Check gutter regularly for debris accumulation
- Clean collar and surrounding area to maintain water shedding
On-site tips and compatibility
This collar is part of a complete VELUX daylight and ventilation solution, so ensure all components are compatible before installation. The pack of 10 units is economical for multiple installations or allows for contingency stock on larger projects. Store collars in dry conditions on site to prevent damage before installation. When ordering, confirm your VELUX window or Sun Tunnel model is compatible with the BFX collar specification to avoid fitting issues. Professional installation is recommended to ensure the weather-tight seal is properly achieved.
- Confirm compatibility with your specific VELUX window model
- Store in dry conditions before installation
- Pack of 10 suits multiple installations or larger projects
- Professional installation recommended for optimal weather performance