Fixing and buying guide

What this product is and who it is for

This is a replacement or installation flashing for VELUX Flat Rooflights. It is for builders, roofers, and serious DIY installers fitting new flat rooflights or replacing damaged flashings on existing installations. The flashing creates the critical watertight seal between the rooflight frame and your roof structure, making it essential for preventing leaks and water damage.

Compatibility and sizing

This flashing is designed specifically for VELUX Flat Rooflights and measures 78x98cm, which accommodates standard VELUX flat rooflight dimensions. It is suitable for flat roofs with a pitch up to 2m and must be installed on timber grades FSC 32 and above. Check your rooflight model and roof timber grade before purchase to ensure compatibility.

• Size: 78 x 98cm (30.5 x 38.6 inches)
• Roof pitch: Up to 2m maximum
• Timber grades: FSC 32 and above only
• Application: VELUX Flat Rooflights exclusively

Material and durability

The flashing is manufactured from UV-stabilised PVC, which resists weathering, UV degradation, and harsh weather exposure. This ensures a long service life and maintains the watertight seal over time without deterioration from sunlight or temperature fluctuations.

• UV-stabilised PVC construction
• Resistant to weathering and UV damage
• Durable finish for residential and commercial use

Pre-installation checks

Before fitting, verify that your roof timber grade is FSC 32 or above and that your roof pitch does not exceed 2m. Confirm the rooflight model is compatible with this 78x98cm flashing size. Inspect the roof structure for damage, rot, or movement, and ensure the installation area is clean and dry. Have all necessary fixings and sealants to hand before beginning work.

• Check timber grade and roof pitch specifications
• Confirm rooflight model compatibility
• Inspect roof structure for damage or movement
• Ensure installation area is clean and dry