How and where to use guide
VELUX Twin and Combination Flashings 55x118cm EKL CK06 S0312
Typical applications
These flashings are used to weatherproof the junction between a roof and an adjoining wall, chimney, or vertical structure. They are commonly installed during new roof construction or when replacing existing flashings. The twin and combination design allows flexibility in how the flashing integrates with your roofing system and wall interface.
- Roof-to-wall junctions on domestic properties
- Chimney flashings on timber or concrete roofs
- Vertical wall penetrations through pitched roofs
- Both new build and renovation projects
Installation and positioning
The flashing must be positioned so that the upper edge sits beneath the roof covering and the lower edge overlaps the wall surface or lower roofing material. This overlapping arrangement ensures water runs down and away from the junction rather than penetrating behind the flashing. The 55 x 118cm size accommodates standard roof pitches and wall heights.
- Install before final roof covering is laid where possible
- Ensure upper edge is tucked under roof tiles, slates, or membrane
- Lower edge should overlap wall surface by at least 150mm
- Seal all joints and edges with appropriate roofing sealant
- Check that water will run downslope away from the junction
Surface compatibility and preparation
The high-quality plastic construction is compatible with both timber and concrete roof substrates. Before installation, ensure the roof surface is clean, dry, and free from debris. Any existing old flashing should be removed completely. The surface must be sound and stable to support the flashing securely.
- Clean timber or concrete surfaces of dirt, moss, and loose material
- Remove old flashings completely
- Repair any damaged roof substrate before installing new flashing
- Allow concrete surfaces to dry fully if recently laid or repaired
Durability and maintenance
The plastic construction provides excellent resistance to harsh environmental conditions and weathering. To maintain long-term performance, inspect flashings annually, particularly after severe weather. Clear any debris from the junction and check that sealant remains intact. The watertight seal depends on proper maintenance of all joints and edges.
- Inspect annually for cracks, gaps, or sealant deterioration
- Clear leaves and debris from the roof-wall junction
- Reapply sealant if gaps appear or existing sealant fails
- Check after storms or high winds for any movement or damage