Fixing and buying guide
VELUX Twin and Combination Flashings 78x140cm EKP MK08 0021E
Who should buy this product
This flashing is for builders, roofers, and serious DIY customers installing or replacing roof windows in timber frame construction. It suits both domestic and commercial applications where a secure, code-compliant watertight seal is required around roof openings up to 140cm in length.
- Timber frame roof construction projects
- Pitched roof installations between 30 and 60 degrees
- New builds and retrofit roof window installations
- Projects requiring FSC-certified sustainable materials
Sizing and compatibility
The 78 x 140cm dimensions suit standard roof openings within this range. Before ordering, confirm your roof pitch falls between 30 and 60 degrees—flashings outside this range will not seal properly. These flashings are compatible with multiple roofing material types, including slate, tile, and sheet materials, making them versatile for most pitched roof applications.
- Roof pitch must be 30–60 degrees
- Opening length up to 140cm
- Works with slate, tile, and sheet roofing materials
- Engineered plastic core resists rot and weathering
What is included and pre-installation checks
Each pack contains the twin and combination flashing unit with engineered plastic core and FSC-certified timber components ready for installation. Before fixing, inspect the flashing for damage, check that your timber frame opening dimensions match the 78 x 140cm specification, and verify your roof pitch is within the 30–60 degree range. Ensure the roof structure is sound and level, and that you have appropriate roofing material ready to bed the flashing into place.
- Inspect flashing for transport damage before installation
- Confirm roof pitch with a level or pitch gauge
- Check timber frame opening is square and true
- Have roofing material and bedding compound ready
Installation and fixing
Position the flashing over the timber frame opening, ensuring it sits level and square. The engineered plastic core and timber components work together to create the watertight seal when properly bedded into your roofing material. Follow VELUX installation guidance for your specific roofing type to ensure the flashing is fully integrated with the roof covering and sealed against water ingress at the frame-to-roof junction.
- Bed flashing into roofing material according to type
- Ensure level installation across the 78 x 140cm span
- Seal all edges to prevent water ingress
- Refer to VELUX technical guidance for your roofing material