Fixing and buying guide

Who this product is for

This flashing is for builders, roofers, and experienced DIY installers carrying out pitched roof window installations. You will need this product if you are installing two VELUX roof windows adjacent to each other or installing one roof window alongside another compatible roof element. Standard single-window installations require a different flashing type.

Compatibility and sizing

This flashing is designed for VELUX roof windows in the MK04 size range and is compatible with the wider VELUX roof window product range. The 78x98cm dimensions suit standard rafter spacing on pitched roofs. Before ordering, confirm that your roof windows are MK04 compatible and that your rafter spacing matches the standard dimensions this flashing is designed for. If your roof has non-standard rafter spacing or different window sizes, you may require alternative flashing components.

• Compatible with VELUX MK04 roof window models
• Sized for standard rafter spacing on pitched roofs
• Suitable for twin window or combination window installations
• Check window model compatibility before purchase

What is included and material

The flashing comprises aluminium and rubber seal components that work together to create a weathertight barrier. The aluminium provides structural support and durability, whilst the rubber seal ensures water cannot penetrate the junction between the window frames and roof structure. This combination of materials is designed to withstand exposure to weather and movement in the roof structure.

Pre-installation checks

Before fixing this flashing, ensure your roof pitch is suitable for standard installations, verify that your windows are the correct MK04 size, and confirm that rafter spacing is standard. Check that the roof area is prepared and ready for window installation. Have the flashing on site before beginning roof work to avoid delays. Ensure you have appropriate safety equipment and access arrangements for working at height on a pitched roof.

• Verify roof pitch is suitable for standard flashing installation
• Confirm window models are MK04 compatible
• Check rafter spacing matches standard dimensions
• Ensure roof structure is prepared and ready
• Have flashing available before starting roof work