Fixing and buying guide

What this product is and who it is for

Twin and combination flashings are metal or PVC trims that sit at the junction between your VELUX skylight or solar tube and the roof surface. They direct water away from the opening and create a weathertight seal. This product is for anyone installing or replacing a VELUX skylight or solar tube, whether you are a professional roofer or a confident DIY installer. The flashing works with both pitched tile and slate roofs, provided the timber structure meets the specified grades.

Compatibility and sizing

This flashing is designed specifically for VELUX skylights and solar tubes and measures 134x140cm. Check your VELUX product documentation or the opening dimensions of your skylight or solar tube to confirm this size matches your installation. The flashing is compatible with roof timber grades F16, F24, and F36. Verify your roof timber grade before purchase; if you are unsure, consult a surveyor or structural engineer. The PVC material is suitable for all standard UK roof pitches and weather conditions.

• Dimensions: 134 x 140cm
• Compatible with VELUX skylights and solar tubes only
• Suitable for timber grades F16, F24, and F36
• PVC construction for durability and weather resistance

What is included and pre-installation checks

Each pack contains one twin and combination flashing unit. Before installation, inspect the flashing for any damage or defects. Ensure your roof opening is clean and free from debris, and that the surrounding timber is sound and dry. Check that your VELUX unit is correctly positioned and level before fitting the flashing. Have all necessary fixings, sealants, and roofing materials to hand before you begin work. If you are working at height, ensure you have appropriate safety equipment and scaffolding in place.

• One flashing unit per pack
• Inspect for damage before use
• Ensure roof opening is clean and debris-free
• Confirm VELUX unit is level and correctly positioned
• Have fixings and sealants ready before starting

Installation and fixing

The flashing should be fitted around the VELUX unit according to the manufacturer's installation instructions, which are supplied with your skylight or solar tube. The flashing sits on the roof surface and is secured with appropriate fixings suitable for your roof covering. Sealant should be applied around the edges to create a watertight seal. The flashing must overlap the roof covering correctly to direct water downslope and away from the opening. If you are not confident in roof work, particularly at height, engage a qualified roofer to carry out the installation.