Fixing and buying guide

What this product is and who it is for

This is a twin and combination flashing system for pitched roof applications. Twin flashings accommodate two roof penetrations or angles, whilst combination flashings handle more complex roof geometry. They are suitable for builders, roofers, and experienced DIY customers installing or replacing roof penetration seals on properties with pitched roofs. The product works with both timber-framed and concrete roof structures.

Compatibility and sizing

The 55x98cm dimensions are designed to provide a snug fit around standard roof penetrations and angled roof sections. Before ordering, measure your roof penetration or angle carefully to confirm this size is appropriate for your installation. These flashings are specifically engineered as VELUX roofing products, so check compatibility with your existing roof system. The metal construction and durable weather-resistant coating are suitable for all UK pitched roof exposures.

• Size: 55x98cm (21.6 x 38.6 inches)
• Material: High-quality metal with durable weather-resistant finish
• Suitable for timber-framed and concrete roof structures
• Designed for pitched roofs with complex angles and curves

Pre-installation checks

Inspect your roof structure and penetration points before installation. Ensure the roof is sound, with no missing tiles, slates, or structural damage. Check that the flashing size matches your roof penetration dimensions. Verify that your roof pitch and angle are compatible with pitched roof flashing systems. Have all necessary roof tiles, slates, or other covering materials ready for reinstallation around the flashing. Ensure you have appropriate safety equipment and access arrangements for working at height.

• Measure roof penetration or angle to confirm 55x98cm size is suitable
• Check roof structure is sound and free from damage
• Confirm roof pitch is suitable for pitched roof flashings
• Gather replacement roof covering materials before starting work

Installation and fixing

These flashings are suitable for DIY installation but require careful positioning to ensure a watertight seal. The flashing must be positioned to overlap existing roof covering above the penetration and be covered by roof covering below. Follow VELUX installation guidance specific to your roof type and structure. Secure the flashing according to manufacturer instructions, ensuring all edges are sealed against wind-driven rain and snow ingress. If you are uncertain about roof work, consult a qualified roofer.