Fixing and buying guide

What this product is for

This twin coupling flashing is used when installing two VELUX roof windows side by side with a 100mm gap between their frames. It bridges the gap between the two windows, creating a continuous weathertight seal that prevents water ingress. The flashing integrates with your roofing material, whether that is slate, corrugated metal sheets, pantiles or thatch, and maintains the weather protection of your roof structure.

Compatibility and sizing

This flashing is specifically designed for VELUX roof windows measuring 66 × 118cm and requires the two windows to be spaced exactly 100mm apart frame to frame. Check your window dimensions before ordering. The flashing accommodates roofing materials with profile heights up to 120mm, which covers most standard profiled tiles and corrugated sheets. Your roof pitch must fall between 15° and 90° for this flashing to perform correctly.

• Window size: 66 × 118cm
• Frame spacing: 100mm between windows
• Roofing profile height: up to 120mm maximum
• Roof pitch range: 15° to 90°
• Compatible with slate, corrugated sheets, pantiles and thatch

Pre-installation checks

Before fitting, measure the distance between your two window frames to confirm it is 100mm. Check your roofing material profile height does not exceed 120mm, and measure your roof pitch to ensure it falls within the 15° to 90° range. Inspect the roof area where the flashing will be installed for any damage or deterioration. Ensure you have the correct VELUX windows in place and that the surrounding roof structure is sound and ready to receive the flashing.

• Confirm both windows are VELUX 66 × 118cm size
• Measure frame spacing: must be 100mm
• Check roof pitch is between 15° and 90°
• Verify roofing profile height does not exceed 120mm
• Inspect roof area for damage before installation

Material and durability

The flashing is manufactured from dark grey lacquered aluminium, which provides excellent durability and corrosion resistance in UK weather conditions. The lacquered finish protects the aluminium from oxidation and UV damage, ensuring long-term weathertightness. This material choice makes the flashing suitable for exposed roof positions and compatible with a variety of roofing materials without risk of incompatibility or degradation.