How and where to use guide
VELUX Standard Flashings 55x98cm EDW CK04 0000
Suitable applications and rooflight sizes
This standard flashing is designed specifically for VELUX rooflights measuring 55×98cm on flat roof installations. It is compatible with timber roof decking graded F16 and F24, which are the most common structural timber grades used in UK flat roof construction. The flashing provides the weatherproofing interface between the rooflight frame and the roof deck, making it essential for any new installation or replacement of a rooflight of this size on a flat roof.
- Use only on flat roofs with compatible VELUX rooflights of 55×98cm dimensions
- Suitable for F16 and F24 timber grades only
- Not suitable for pitched roofs or alternative rooflight brands
- Required for both new installations and rooflight replacements
Installation and securing the flashing
The 25mm overlap built into this flashing design is critical for secure fixing and watertight performance. When installing, position the flashing around the rooflight frame so that the overlap extends onto the surrounding roof deck. This overlap must be properly secured to the timber deck using appropriate fixings such as stainless steel screws or galvanised fasteners suitable for plastic and timber. Ensure the flashing sits flush against the rooflight frame perimeter with no gaps or lifting. The straightforward design allows for quick installation once the rooflight opening is prepared to the correct dimensions.
- Position flashing with 25mm overlap extending onto roof deck
- Secure overlap using stainless steel or galvanised fixings at 150-200mm centres
- Ensure flashing sits flush with no gaps around rooflight frame
- Check that all edges are properly seated before final fixing
Weatherproofing and maintenance
The durable plastic construction of this flashing resists weathering and maintains its watertight seal over time. Once installed, the flashing requires minimal maintenance. Periodically inspect the flashing and fixings, particularly after severe weather, to ensure the seal remains intact and no water is pooling around the rooflight perimeter. Keep the roof deck around the flashing clear of debris and standing water. If the roof deck is subsequently covered with roofing felt or membrane, ensure these materials are properly sealed to the flashing edge to maintain the watertight integrity of the installation.
- Inspect flashing and fixings regularly for damage or movement
- Clear debris and standing water from around the rooflight
- Ensure any roofing felt or membrane is sealed to the flashing edge
- Replace flashing if cracks, splits or permanent deformation occur
On-site handling and storage
Store the flashing in a dry location before installation to prevent any moisture absorption or warping. Handle carefully to avoid damage to the plastic edges, which must remain straight and undamaged to ensure a proper seal. Protect the flashing from direct sunlight during extended storage periods, as this can affect the plastic properties. On site, keep the flashing clean and free from dust, debris and paint splashes until installation is complete.
- Store in a dry, sheltered location away from direct sunlight
- Protect edges from damage during handling and transport
- Keep clean until installation to prevent debris becoming trapped under flashing
- Do not force or bend the flashing during installation