How and where to use guide
VELUX Vapour Barrier 94x140cm BBX PK08 0000
Where to use this product
Install the VELUX Vapour Barrier Collar at the point where your VELUX roof window or Sun Tunnel penetrates the roof structure. The collar sits between the roof deck and the window frame, creating a continuous vapour barrier that prevents warm, moist air from the interior from reaching the cold roof surface. This is particularly important in UK properties where condensation risk is high due to temperature and humidity variations. The collar is suitable for use in both new build installations and refurbishment projects where existing roof windows are being replaced or upgraded.
- VELUX roof window installations (standard range)
- VELUX Sun Tunnel systems
- New build construction projects
- Refurbishment and replacement work
Installation and positioning
Position the vapour barrier collar around the roof window or Sun Tunnel frame before final sealing. The collar dimensions of 940 × 1400mm are engineered to fit the PK08 window size. Ensure the collar is laid flat and fully adhered to the roof structure and window frame, with no gaps or wrinkles that could allow air or moisture to bypass the seal. The barrier should be continuous and overlap properly with any adjacent membranes or insulation. Work methodically around the entire perimeter to guarantee a complete weather-tight seal. Pay particular attention to corners and edges where moisture ingress is most likely.
- Fit the collar before installing roof covering materials
- Ensure full contact with both roof deck and window frame
- Overlap adjacent membranes correctly
- Check for gaps, wrinkles or damage before sealing
Weather protection and performance
The vapour barrier collar is engineered to perform reliably in typical UK roof conditions, including heavy rain, wind-driven moisture, and temperature fluctuations. Once correctly installed, it creates a durable, weather-tight seal that protects the building interior and structural elements from moisture damage. The collar supports a neat, professional roof finish and maintains its integrity throughout the life of the window installation. Regular inspection during and after installation will confirm that the seal remains intact and effective.
- Protects against rain penetration and wind-driven moisture
- Prevents condensation forming on cold roof surfaces
- Maintains seal integrity in UK weather conditions
- Supports professional appearance and long-term durability
Compatibility and maintenance
This vapour barrier collar is specifically designed for VELUX roof window and Sun Tunnel systems in the PK08 size range. Always confirm compatibility with your window model before ordering. Once installed, the collar requires no routine maintenance. However, inspect the seal periodically—particularly after severe weather or if you notice any signs of moisture, condensation, or water staining around the window frame. If damage is detected, the collar should be replaced to maintain the weather-tight integrity of the installation.
- Confirm PK08 compatibility with your VELUX window or Sun Tunnel
- No routine maintenance required after installation
- Inspect periodically for signs of damage or moisture ingress
- Replace if seal is compromised to maintain building protection