Fixing and buying guide

What is included and who needs this kit

This is a complete flashing system for VELUX roof windows and Sun Tunnel installations. It comes with the flashing and both BDX and BFX installation products, so you have everything required for fitting. Use this kit if you are installing a VELUX window or Sun Tunnel into a single plain tile roof and your tiles are no thicker than 14mm. The kit works for both new build projects and refurbishment of existing roofs.

Compatibility and sizing

This flashing is engineered for the UK08 window size, which has an aperture of 1340×1400mm. Check that your VELUX window or Sun Tunnel is UK08 size before ordering. The flashing is designed specifically for single plain tile roofs; if your roof uses different tile types (such as interlocking or concrete tiles) or if tiles exceed 14mm thickness, you will need a different flashing kit. Confirm your tile thickness and type before purchase.

• Aperture size: 1340×1400mm (UK08)
• Maximum tile thickness: 14mm
• Tile type: single plain tiles only
• Compatible with VELUX roof windows and Sun Tunnel systems

Pre-installation checks

Before you begin, measure your roof opening to confirm it matches the UK08 aperture size. Check that your plain tiles are no thicker than 14mm by measuring a sample tile. Verify that the roof structure is sound and that the opening is square and level. Ensure you have adequate access and working space on the roof. Have the BDX and BFX installation products to hand and read the VELUX installation instructions carefully before starting work.

• Confirm window size is UK08 (1340×1400mm aperture)
• Measure plain tile thickness; must not exceed 14mm
• Check roof opening is square and level
• Inspect roof structure for soundness
• Review VELUX installation instructions before fitting

Installation overview

This kit delivers a weather-tight seal and consistent roof appearance when fitted correctly. The included BDX and BFX installation products support a neat, professional finish. Follow the VELUX installation guide step by step, ensuring the flashing is properly bedded into the tiles and sealed. The complete kit approach means you should not need to source additional components separately, provided your roof meets the specified conditions.