Fixing and buying guide

What this product is and who needs it

The vapour barrier collar is a specialist component designed specifically for VELUX roof window and Sun Tunnel installations. It creates a weather-tight seal at the point where the window or tunnel penetrates the roof, protecting the building fabric from water ingress and condensation. This product is essential for both professional installers and serious DIY customers undertaking roof window installations in new build properties or refurbishment projects.

Compatibility and sizing

This collar is sized FK06 and measures 660 × 1180mm. It is compatible with VELUX roof windows and Sun Tunnel systems specified for this size. Before purchasing, confirm that your VELUX window or tunnel system requires the FK06 size collar. Check your VELUX product documentation or specification sheet to verify compatibility, as using an incorrectly sized collar will compromise the weather-tight seal and installation quality.

• Designed for VELUX roof windows and Sun Tunnel systems only
• Size FK06: 660 × 1180mm
• Verify compatibility with your specific VELUX product before ordering
• Part of a complete installation system, not a standalone product

Pre-installation checks and preparation

Before fitting the vapour barrier collar, ensure your roof opening is correctly sized and prepared according to VELUX installation guidelines. The roof structure must be sound and the opening must be clean and free from debris. Check that all other components of your VELUX installation kit are present and undamaged. The collar should be fitted as part of the complete installation sequence, following the manufacturer's instructions to ensure the weather-tight seal is properly achieved.

• Verify roof opening dimensions match VELUX specifications
• Ensure the opening is clean and free from dust and debris
• Check all installation components are present before starting work
• Follow VELUX installation instructions for correct collar positioning
• Fit the collar as part of the complete installation system

Performance and maintenance

The vapour barrier collar is engineered to perform reliably in typical UK roof conditions, providing a durable weather-tight seal when correctly installed. Once fitted, the collar requires no routine maintenance but should be visually inspected periodically as part of general roof maintenance to ensure the seal remains intact and there are no signs of water ingress around the installation.