Fixing and buying guide

What this product is and who it is for

These are perimeter flashings for flat rooflights, not roof windows. They form a critical watertight barrier around the rooflight opening where it meets the roof structure. They are suitable for both domestic and commercial applications where flat rooflights are being installed or replaced. If you are fitting a flat rooflight into a timber-framed roof, you will need these flashings to prevent water penetration around the opening edges.

Compatibility and sizing

These flashings are sized 134 x 140cm and are designed for use with flat rooflights of matching dimensions. They are compatible with timber roof structures graded F16, F24, and F32, which covers standard structural timber used in UK domestic and commercial roofing. Check your rooflight manufacturer's specifications to confirm this flashing size matches your rooflight model before ordering.

• Dimensions: 134 x 140cm
• Compatible timber grades: F16, F24, F32
• Material: PVC construction
• Verify rooflight model compatibility before purchase

Key features and performance

The Enhanced Drainage Performance (EDP) rating is the defining feature of these flashings. This rating ensures water runs off quickly and efficiently rather than pooling around the rooflight perimeter, which is critical for preventing water ingress. The durable PVC material resists degradation from UV exposure, temperature fluctuations, and weather exposure typical of UK roof conditions.

• Enhanced Drainage Performance (EDP) rating for efficient water run-off
• Watertight seal around entire rooflight perimeter
• Durable PVC withstands environmental exposure
• Suitable for exposed roof locations

Pre-installation checks and preparation

Before fitting, confirm that your rooflight opening dimensions match the 134 x 140cm flashing size. Check that your roof structure timber grade falls within F16, F24, or F32. Ensure the rooflight opening is square and level, as flashings rely on proper roof geometry to function effectively. Have the rooflight unit on site before installing flashings, as installation is carried out in conjunction with the rooflight itself. Review the rooflight manufacturer's installation instructions, as flashing installation sequence may be specified there.