Fixing and buying guide

What this product is and who needs it

The vapour barrier collar is an essential sealing component for VELUX roof window and Sun Tunnel installations. It prevents water ingress and manages moisture vapour at the roof penetration, ensuring a weather-tight seal that maintains the integrity of your roof structure. This product is required for anyone installing a compatible VELUX roof window or Sun Tunnel system, whether in a new build property or during refurbishment work.

Compatibility and sizing

This collar is compatible with the standard VELUX roof window and Sun Tunnel ranges and is sized at 940 × 1400mm (PK08). Before ordering, confirm that your VELUX window or Sun Tunnel system uses the PK08 size specification. Check your installation documentation or product code to ensure compatibility. Using the correct size is essential for a proper weather-tight fit.

• Product code PK08 0000 — verify this matches your VELUX system
• Dimensions 940 × 1400mm — confirm your roof opening matches this specification
• Compatible with standard VELUX roof window and Sun Tunnel ranges

Installation and preparation

The vapour barrier collar should be installed as part of the roof window or Sun Tunnel fitting process, following VELUX installation guidance. Ensure the roof opening is prepared to the correct dimensions and that the surrounding roof structure is clean and dry before fitting. The collar must be positioned to create a continuous weather-tight seal around the window or tunnel frame. Professional installation is recommended to ensure long-term performance and to maintain warranty cover.

• Install as part of the complete VELUX window or Sun Tunnel system
• Ensure roof opening is prepared to specification
• Position collar to create a continuous weather-tight seal
• Follow VELUX installation instructions for your specific product

Pre-installation checks

Before fitting, verify that you have the correct PK08 size for your VELUX system and that all components of your window or Sun Tunnel installation are present. Check that the roof opening dimensions match the 940 × 1400mm specification and that the surrounding roof structure is sound and ready to receive the installation. Confirm that you have access to the full VELUX installation documentation for your specific window or Sun Tunnel model.

• Confirm product code PK08 0000 matches your system
• Check roof opening dimensions are correct
• Verify roof structure is sound and ready for installation
• Have VELUX installation documentation to hand