Fixing and buying guide

What this product is and who it is for

This is a standard plastic flashing kit for VELUX rooflights on flat roofs. It is designed for anyone installing or replacing a 55×98cm VELUX rooflight on a flat roof with timber joists graded F16 or F24. Both experienced roofers and competent DIY installers can use this product, provided they have appropriate access equipment and roofing experience.

Compatibility and sizing

This flashing is sized specifically for VELUX rooflights measuring 55×98cm. It is compatible only with timber grades F16 and F24. Before ordering, confirm your rooflight dimensions and check that your roof structure uses one of these timber grades. The 25mm overlap is built into this flashing design and cannot be adjusted.

• Rooflight size: 55×98cm
• Timber grades: F16 and F24 only
• Overlap: 25mm (fixed)
• Application: Flat roofs only

What is included and pre-installation checks

Each flashing is a single unit made from durable plastic. Before installation, inspect the flashing for damage and ensure your rooflight dimensions match 55×98cm exactly. Check that your roof structure is sound, level, and uses compatible timber grading. Verify that the roof deck is clean and free from debris where the flashing will sit. Confirm you have appropriate fall protection and access equipment for safe working at height.

• Inspect flashing for cracks or damage before use
• Confirm rooflight size matches 55×98cm
• Check timber grade is F16 or F24
• Ensure roof deck is clean and level
• Arrange safe access and fall protection

Installation overview

The flashing is designed for straightforward installation on flat roofs. Position it around the rooflight perimeter so the 25mm overlap sits securely on the surrounding roof deck. The durable plastic construction resists weathering and the overlap design prevents water running back under the flashing. Follow VELUX installation instructions for your specific rooflight model to ensure correct positioning and any additional fixings required. Proper installation of this flashing is essential to maintain a watertight seal and prevent water damage to the roof structure.