How and where to use guide
VELUX ETW WK34 0000F COMBI TILE FLASHING FOR GIL/U 120mm
Typical applications
This combi tile flashing is used on pitched tile roofs where a gill or underlay system is in place. It provides the critical weatherproofing interface between individual roof tiles and the underlying roof structure. The 120mm width is suited to standard tile installations on domestic and light commercial properties. The flashing accommodates the natural movement and settlement of roof tiles whilst maintaining a continuous water barrier.
- Pitched tile roofs with gill or underlay systems
- Standard domestic and light commercial tile roof installations
- Roofs constructed with F16 or F24 timber grades
- Situations requiring site-specific flashing adaptation
Installation and site fitting
The flashing should be positioned to create a seal between the tile and the roof substrate, with the gill or underlay system underneath. Before installation, measure the required length carefully and cut the flashing to size using a sharp saw or mitre box. Ensure cuts are clean and square to maintain watertight performance. Position the flashing so that it sits securely in place and does not create gaps or overlaps that could allow water penetration. Work systematically across the roof, ensuring each section is properly seated before moving to the next.
- Measure and cut flashing to required length using a saw or mitre box
- Ensure the gill or underlay is in place before fitting flashing
- Position flashing to create a continuous seal with no gaps
- Check that flashing sits level and secure on the roof substrate
- Work methodically to maintain consistent installation quality
Material properties and durability
The polypropylene and polyester construction provides durable weather resistance suitable for long-term roof exposure. This material combination resists UV degradation, moisture absorption, and temperature fluctuations typical of UK roof environments. The flashing maintains its integrity through seasonal movement and thermal cycling without becoming brittle or losing its waterproofing properties. Regular visual inspection is recommended to ensure the flashing remains in good condition and that no cracks or separation has occurred.
- Polypropylene and polyester resist weather exposure and UV damage
- Material remains flexible through temperature changes
- Inspect flashing annually for cracks, separation, or deterioration
- Clean debris from flashing to prevent water pooling
Limitations and site considerations
This flashing is designed specifically for tile roofs with gill or underlay systems and is not suitable for other roof types. The 120mm width is fixed and cannot be extended, so measure your roof carefully before ordering. The flashing must be cut to length on site using appropriate tools; improper cutting or installation can compromise the watertight seal. Do not use on timber grades below F16, as the structural integrity of the roof support may be insufficient. Always ensure the gill or underlay system is properly installed before fitting the flashing.
- Suitable only for tile roofs with gill or underlay systems
- Width is fixed at 120mm and cannot be extended
- Requires proper cutting technique to avoid damage
- Must be used with F16 or F24 timber grades only
- Gill or underlay must be in place before flashing installation