How and where to use guide
VELUX Twin and Combination Flashings 55x118cm EBL CK06 0021B
Typical applications and suitability
These twin and combination flashings are primarily used to seal around VELUX rooflights and skylights where they penetrate the roof plane. They are equally suitable for general window and door installations in pitched roof situations. The 55 x 118cm size accommodates standard roof window openings. The vinyl construction performs well in exposed locations subject to wind-driven rain, frost and UV exposure. They work across timber-framed roofs, brick and concrete substrates, making them versatile for most UK residential and light commercial roof applications.
- VELUX rooflights and skylights
- Roof windows and doors in pitched roofs
- Standard roof penetrations up to 55 x 118cm
- Timber, brick and concrete roof structures
Installation and fixing
Proper installation is essential for effective weather protection. The flashing must be positioned to overlap the roof covering above and sit securely against the substrate below. Use suitable fixings appropriate to your substrate—stainless steel fasteners for timber, corrosion-resistant fixings for brick and concrete. Follow VELUX manufacturer guidance for positioning and securing the flashing to ensure the weather-tight seal functions correctly. Pay particular attention to the upper edge, which must overlap the roof tiles or slates, and the lower edge, which should sit firmly on the roof covering.
- Use stainless steel or corrosion-resistant fixings
- Ensure upper edge overlaps roof covering
- Secure lower edge firmly to roof surface
- Follow VELUX installation instructions for your specific rooflight model
- Check all fixings are tight before exposing to weather
Maintenance and durability
The robust vinyl construction is designed to withstand harsh UK weather conditions without degradation. Inspect flashings annually, particularly after severe weather, to ensure fixings remain tight and the seal is intact. Clear any debris, moss or lichen growth from the flashing surface to maintain water run-off. The vinyl material does not require painting or coating, though it should be kept clean. If damage occurs—such as cracks or separation from the substrate—the affected flashing should be replaced to maintain weather protection.
- Inspect annually for loose fixings or damage
- Clear debris and organic growth to maintain drainage
- No painting or treatment required
- Replace if cracks or separation develop
- Check seals after severe weather or high winds
Limitations and on-site considerations
These flashings are sized for standard roof penetrations; non-standard opening sizes may require additional sealing or alternative products. The vinyl material is durable but can become brittle in extreme cold during installation, so handle carefully in winter conditions. Ensure the roof substrate is sound and properly prepared before installation—loose or damaged tiles, slates or concrete will compromise the seal. The flashing relies on correct overlap and fixing; poor installation will result in water ingress. Do not use on flat roofs or in applications where water ponding may occur, as the design is intended for pitched roof drainage.
- Sized for standard roof openings only
- Handle carefully in cold weather
- Requires sound, properly prepared substrate
- Not suitable for flat roofs or ponding water situations
- Correct overlap and fixing are critical to performance