How and where to use guide
VELUX Recessed Flashings 134x98cm EDJ UK04 0000
Suitable applications and installation locations
This recessed flashing is designed for pitched roof installations where a roof window penetrates the building envelope. It works effectively in timber frame construction, concrete slab roofs and brickwork applications. The flashing sits recessed into the roof structure to create a secure seal between the window frame and surrounding roof fabric. It is suitable for new installations during roof construction or replacement work where the roof structure is exposed and accessible for proper flashing installation.
- Timber frame roofs with rafters and boarding
- Concrete slab roofs with appropriate substrate preparation
- Brickwork and masonry roof structures
- Standard roof window sizes up to 134×98cm
- Pitched roof applications where recessed installation is possible
Installation and on-site preparation
The recessed design requires careful positioning during roof construction or when the roof structure is exposed. The flashing must be installed before the roof covering is laid, ensuring the recessed edges sit flush with the surrounding roof structure. Proper alignment is essential to create an effective weathertight seal. The treated timber should be handled carefully to avoid damage to the protective coating, and any cut edges should be sealed with appropriate wood preservative to maintain rot resistance.
- Install during roof construction before roof covering is applied
- Ensure recessed edges align flush with surrounding roof structure
- Secure flashing firmly to prevent movement or settlement
- Seal any cut edges with wood preservative
- Allow adequate clearance for roof covering to overlap flashing edges
Finishing and maintenance
The treated timber flashing can be finished with paint or stain to match surrounding roof timbers and surfaces. This finishing step protects the timber and improves appearance. Once installed and finished, the flashing requires minimal maintenance due to its treated timber construction and rot-resistant properties. Periodic inspection of the roof window seal and surrounding flashing is recommended to ensure the weathertight seal remains intact, particularly after severe weather.
- Paint or stain to match existing roof timbers and finishes
- Apply finish before final roof covering installation
- Inspect flashing annually for signs of damage or deterioration
- Check weathertight seal around window frame remains intact
- Treated timber resists rot and insect damage in exposed conditions
Limitations and important considerations
This flashing is designed specifically for recessed installation in timber and concrete construction. It is not suitable for applications where recessed installation is not possible or where the roof structure cannot accommodate the flashing depth. The 134×98cm size is fixed and suits standard roof window installations; non-standard window sizes may require alternative flashing solutions. Proper installation is critical to performance; inadequate sealing or misalignment will compromise weathertightness and allow water ingress.
- Requires recessed installation into roof structure
- Not suitable for flat roofs or applications without recessed capability
- Fixed size suits standard roof windows only
- Installation must be completed before roof covering application
- BS 4764 compliance requires correct installation and finishing