Fixing and buying guide

What this product is and who needs it

Tile flashing is the weatherproofing interface between your Velux roof window and the surrounding roof tiles. This kit is designed specifically for Velux 3-in-1 roof windows and includes the BDX and BFX components required for complete installation. It is essential for both new build installations and refurbishment work where you are fitting a roof window into an existing tiled pitched roof. Without proper flashing, water ingress and air leaks will compromise the roof's integrity.

Compatibility and sizing

This flashing is sized at 1880×1400mm and is engineered exclusively for Velux 3-in-1 roof windows that accept BDX and BFX components. Before ordering, confirm your roof window model number matches this specification. The flashing is designed for pitched tile roofs in typical UK roof conditions. Check your roof pitch and tile profile against Velux installation documentation to ensure compatibility with your specific installation.

• Dimensions: 1880×1400mm
• Compatible with Velux 3-in-1 roof windows only
• Requires matching BDX and BFX compatible window
• Suitable for pitched tile roofs

What is included and pre-installation checks

This kit includes both the BDX and BFX components needed for a complete weather-tight installation. Before you begin, inspect all components for damage in transit. Verify your roof window frame is clean and undamaged, and check that the surrounding roof structure is sound and level. Ensure you have the correct roof window model to hand and review the Velux installation instructions specific to your window type. Confirm adequate working space around the installation area and that weather conditions are suitable for roof work.

• Includes BDX and BFX components
• Inspect for transit damage before installation
• Verify roof window model compatibility
• Check roof structure is sound and level
• Review Velux installation instructions for your window

Installation and weather-tight performance

This flashing must be installed according to Velux's detailed instructions to achieve a weather-tight seal. The aluminium and composite construction is engineered to integrate seamlessly with your roof tiles and window frame, creating a professional finish. Proper installation is critical to prevent water ingress and maintain the roof's weather resistance. If you are not experienced in roof work, engage a qualified roofer or installer familiar with Velux systems. Once installed correctly, the flashing will provide reliable long-term protection in UK roof conditions.