How and where to use guide
VELUX Twin and Combination Flashings 78x140cm EKW MK08 0021E
Suitable applications and roof types
This flashing is engineered for three main roof configurations. On flat roofs, it provides a secure perimeter seal around ventilation penetrations where water pooling is a concern. On pitched roofs, the flashing accommodates the slope and directs water away from the opening. At roof pitch transitions, where two different roof angles meet, the combination design allows the flashing to bridge both surfaces, maintaining a continuous watertight barrier. The 78cm × 140cm size makes it suitable for standard VELUX roof vent installations and compatible ventilation systems on domestic and light commercial properties.
- Flat roofs: creates watertight seal around ventilation openings
- Pitched roofs: accommodates roof slope and directs water runoff
- Roof pitch transitions: bridges different roof angles with combination design
- Compatible with VELUX roof vents and standard ventilation systems
Installation and timber compatibility
The twin flashing design connects to both sides of the ventilation opening, simplifying the installation process and reducing the risk of gaps or misalignment. The flashing is compatible with timber grades F16 and F24, which are standard structural timber grades used in UK roof construction. The PVC material is durable and weather-resistant, providing long-term protection against rain penetration. During installation, ensure the flashing sits flush against the roof surface and the ventilation opening, and that all edges are properly sealed to prevent water ingress. The generous 78cm × 140cm dimensions provide ample working space, allowing installers to position and secure the flashing without unnecessary difficulty.
- Twin design connects both sides of opening for secure, aligned installation
- Compatible with F16 and F24 timber grades used in UK roof construction
- PVC construction resists weathering and maintains flexibility in temperature changes
- Ensure flashing sits flush and all edges are sealed during installation
On-site handling and maintenance
Store the flashing flat and protected from direct sunlight before installation to prevent PVC degradation. During installation, handle carefully to avoid creasing or tearing the material. Once installed, inspect the flashing periodically, particularly after severe weather, to ensure seals remain intact and no debris has accumulated around the ventilation opening. Clear any moss, leaves, or dirt that may obstruct water drainage around the flashing perimeter. The PVC material requires minimal maintenance but should be checked annually as part of routine roof inspections to confirm the watertight seal is maintained and no cracks or separation has occurred at the edges.
- Store flat and protected from sunlight before installation
- Handle carefully during installation to avoid creasing or damage
- Inspect periodically after severe weather for seal integrity
- Clear debris and moss from around the flashing perimeter annually