How and where to use guide
VELUX Twin and Combination Flashings 78x98cm EBP MK04 0021B
Typical applications and installation
This flashing is used in timber frame construction to seal the junction between roof or wall openings and window or door frames. Install the flashing around the perimeter of the opening before fitting the window or door unit, ensuring it sits flush against the timber frame. The flashing should be positioned to direct water away from the frame and down the external surface. Work systematically around the opening, securing the flashing firmly to prevent movement during subsequent construction stages. The 4mm thickness provides adequate structural integrity whilst remaining flexible enough to accommodate minor frame variations.
- Install before fitting windows or doors into timber frame openings
- Position to direct water runoff away from the frame
- Secure firmly to prevent movement during construction
- Suitable for roof pitches and building runs up to 9m
- Use in conjunction with other VELUX products for complete weatherproofing
Material properties and durability
The flashing is constructed from FSC-certified birch plywood, confirming sustainable sourcing from responsibly managed forests. The 4mm thickness balances structural strength with workability on site. Boron-based preservative treatment protects the plywood against rot and insect damage, extending the service life of the component in exposed external conditions. This treatment is particularly important in damp climates and areas prone to timber decay.
- FSC-certified birch plywood ensures sustainable material sourcing
- Boron-based preservative resists rot and insect attack
- 4mm thickness provides structural integrity without excessive weight
- Suitable for long-term external exposure in timber frame buildings
On-site handling and maintenance
Store the flashing flat and dry on site to prevent warping or moisture absorption before installation. Handle carefully to avoid damage to the plywood edges, which could compromise the watertight seal. Once installed, the flashing requires no routine maintenance beyond general building inspection to ensure it remains properly seated and undamaged. Check periodically that the seal around windows and doors remains intact, particularly after severe weather or structural movement.
- Store flat and dry before installation to prevent warping
- Handle carefully to protect plywood edges from damage
- Inspect periodically to ensure seal integrity around openings
- Check after severe weather or if structural movement occurs