Fixing and buying guide

Who needs this product

The vapour barrier collar is required for anyone installing or replacing a VELUX MK06 roof window or Sun Tunnel system. It is essential in new build projects to meet building regulations and moisture control standards, and equally important in refurbishment work to ensure the existing roof structure is properly protected. Installers, builders, and serious DIY customers undertaking roof window installation should include this component in their specification.

Compatibility and sizing

This collar is specifically engineered for VELUX MK06 roof windows and compatible Sun Tunnel systems. The 780 × 1180mm dimensions are fixed to this window size, so you must verify your roof window model before ordering. Check your existing window documentation or the VELUX product label to confirm MK06 compatibility. Using an incorrect collar size will compromise the weather-tight seal and void the installation warranty.

• Compatible only with VELUX MK06 roof windows and accessories
• Fixed dimensions: 780 × 1180mm
• Verify window model before purchase
• Incorrect sizing will compromise weather protection

Installation and pre-install checks

Before fitting the vapour barrier collar, inspect the roof opening to ensure it is clean, dry, and free from debris or old sealant. The collar must be positioned at the roof penetration point, creating a continuous seal between the window frame and the roof structure. Ensure the roof surface is level and stable, and that all flashing and weatherproofing components are ready for installation. The collar works as part of a complete sealing system, so follow VELUX installation guidance carefully and use compatible flashings and sealants as specified.

• Clean and dry the roof opening thoroughly before installation
• Check roof surface is level and structurally sound
• Position collar at the roof penetration point
• Use compatible VELUX flashings and sealants
• Follow VELUX installation instructions for weather-tight performance

Pack contents and durability

Each pack contains one vapour barrier collar sized for MK06 windows. The collar is engineered with weather-resistant materials to perform reliably in UK roof conditions, including exposure to rain, wind, and temperature variation. Proper installation is essential to achieve long-term durability and prevent moisture-related issues such as condensation or structural damage. Store the collar in dry conditions before installation and handle carefully to avoid damage to the sealing surfaces.