How and where to use guide
VELUX Twin and Combination Flashings 134x140cm EBL UK08 0021B
Suitable applications and roof types
These flashings are designed specifically for VELUX skylights and solar tube installations on pitched roofs with timber structural grades F16, F24, and F36. The 134x140cm dimensions suit standard roof window openings. They work with both slate and tile roof coverings and are suitable for use on domestic and light commercial properties. Confirm your roof timber grade before purchase, as this flashing is not suitable for other structural timber specifications.
- VELUX skylight and solar tube installations only
- Pitched roofs with timber grades F16, F24, or F36
- Standard roof openings measuring approximately 134x140cm
- Compatible with slate and tile roof coverings
Installation and positioning
The flashing must be positioned to overlap the roof covering below the window opening and sit beneath the covering above it, creating a stepped water-shedding profile. Install the flashing before laying the final roof covering around the window perimeter. Ensure the flashing sits flush against the roof plane with no gaps or bridging that could allow water to pool. The PVC material should be secured according to VELUX installation instructions, typically using stainless steel fixings to prevent corrosion. Work from the lowest point of the roof opening upwards to maintain proper water drainage.
- Position flashing to overlap roof covering below the opening
- Install before final roof covering is laid around the window
- Ensure flush contact with the roof plane throughout
- Use stainless steel fixings to prevent corrosion
- Work from lowest to highest point of the opening
Maintenance and durability
PVC flashings are durable and weather-resistant, requiring minimal maintenance. Inspect the flashing annually, particularly after severe weather, to ensure all fixings remain secure and the seal is intact. Clear any debris, moss, or lichen from the flashing surface to maintain water drainage. Do not use abrasive cleaners or high-pressure washing directly on the flashing, as this may damage the seal or dislodge fixings. If cracks, splits, or separation from the window frame are observed, the flashing should be resealed or replaced to prevent water ingress.
- Inspect annually for loose fixings or seal deterioration
- Clear debris and organic growth to maintain drainage
- Avoid abrasive cleaners and high-pressure washing
- Reseal or replace if cracks or separation develop
Important limitations and safety notes
This flashing is designed exclusively for VELUX skylights and solar tubes and must not be used with other window or tube manufacturers. Confirm timber grade compatibility before installation, as use on unsuitable structural timber may compromise performance. The flashing provides the weather seal only and must be installed as part of a complete VELUX roofing system following the manufacturer's detailed installation instructions. Roof work should be carried out by competent persons following safe working practices at height. Do not attempt installation on steep or unstable roof pitches without appropriate safety equipment and training.
- VELUX products only—not compatible with other manufacturers
- Verify timber grade F16, F24, or F36 before purchase
- Must be part of a complete VELUX installation system
- Roof work requires competent persons and safe working practices at height