Fixing and buying guide

What this product is and who needs it

This vapour barrier collar is a flashing component that sits between your roof window or Sun Tunnel and the roof structure. It creates a weather-tight seal at the point where the window penetrates the roof, preventing water and moisture from entering the building fabric. Installers, builders, and serious DIY customers carrying out roof window installations or replacements will need this collar to ensure a compliant, durable installation.

Compatibility and sizing

The CK02 0000 collar is designed for standard VELUX roof window and Sun Tunnel ranges. Before ordering, confirm that your VELUX window or tunnel system is compatible with the CK02 size. The collar dimensions are 550×780mm, which suits the specified VELUX product range. Check your window documentation or product code to verify compatibility; using an incorrect collar size will compromise the weather-tight seal.

• Confirm your VELUX window or Sun Tunnel model is compatible with CK02 collars
• Dimensions are fixed at 550×780mm — do not attempt to modify or force fit
• Check product codes on your existing window or installation instructions

Pre-installation checks and preparation

Before fitting, inspect the collar for any damage or defects. Ensure the roof opening is clean, dry, and free from debris, dust, and old sealant. Check that the roof structure around the penetration is sound and level. Have all necessary flashing materials, sealants, and fixings to hand before starting work. Refer to the VELUX installation guide supplied with your window system for specific fitting instructions and the correct sequence of assembly.

• Inspect the collar for damage before installation
• Clean and dry the roof opening thoroughly
• Gather all flashing, sealant, and fixing materials in advance
• Follow the VELUX installation guide for your specific window model

Pack contents and what to expect

This product is the vapour barrier collar only. It forms part of the complete flashing and installation system for your VELUX roof window or Sun Tunnel. You will also need the appropriate window frame, flashing kit, and sealants as specified in your VELUX system documentation. Order all components together to ensure a complete, compatible installation.