Fixing and buying guide

What this product is and who needs it

This is a recessed flashing—a component that sits flush with the roof structure to channel water away from roof window openings. It is designed for builders, roofers, and serious DIY installers working on pitched roof projects where VELUX windows are being fitted. The flashing prevents water pooling and penetration at the junction between the window frame and the roof surface, which is essential for protecting the building interior from damp and structural damage.

Compatibility and sizing

The EDN FK06 is compatible with timber roof constructions using F16, F24, or F36 timber grades, and also suits concrete roof constructions. The 66×118cm dimensions are sized for standard roof window installations. Before ordering, confirm that your roof window opening and surrounding structure match these dimensions and that your timber grading falls within the F16 to F36 range. Check your roof design drawings or existing window specifications to ensure correct fit.

• Suitable for F16, F24, and F36 timber grades
• Works in both timber and concrete constructions
• 66×118cm size for standard roof window applications
• Suitable for domestic and commercial projects

Pre-installation checks

Before fitting, inspect the roof structure around the window opening to ensure it is sound, level, and free from rot or damage. The roof surface must be clean and dry. Check that the opening dimensions match the 66×118cm flashing size and that the surrounding timber or concrete is in good condition. Verify that all necessary roof membrane, battens, and counter-battens are in place and properly secured. Have all fixings and sealants to hand before starting work.

• Confirm opening dimensions match 66×118cm flashing size
• Inspect timber or concrete for rot, cracks, or damage
• Ensure roof surface is clean and dry
• Check that roof membrane and battens are correctly installed
• Gather all fixings and sealants before beginning

Installation and performance

Careful alignment with the roof structure is essential for effective water management. The recessed design allows the flashing to sit flush with the roof, reducing the risk of water pooling. The high-quality plastic construction with durable finish provides long-term weather resistance. Once installed, the flashing should create a continuous watertight seal that directs rainwater safely away from the window frame and into the roof drainage system. Proper installation ensures the flashing performs effectively throughout its service life.