Fixing and buying guide

What this product is and who it is for

This is an external cover set that frames and seals around VELUX roof windows and Sun Tunnel systems. It is for builders, roofers, and serious DIY installers who need to finish a roof window installation with a neat, weather-tight profile. The anodised aluminium construction provides durability and a professional appearance on the roof line. It suits both new installations and refurbishment work where you are upgrading or replacing existing roof windows.

Compatibility and sizing

This cover set is compatible with the standard VELUX roof window and Sun Tunnel ranges. The dimensions of 940mm × 980mm are specific to the PK04 size category, so you must verify that your VELUX window matches this size before ordering. Check your existing window model number or the specification of the new window you are installing. The set includes the top flashing section, so no additional flashing components are needed for the top edge.

• Confirm your VELUX window is PK04 size (940mm × 980mm)
• Compatible with standard VELUX roof window and Sun Tunnel systems
• Top flashing section is included in this set

Pack contents and material

The set contains the external window cover profile and the top flashing section as a complete assembly. The material is anodised aluminium, which provides corrosion resistance and a durable finish suitable for exposure to UK weather. The anodised finish also maintains a consistent appearance on the roof line and requires minimal maintenance once installed.

• External cover profile with integrated top flashing
• Anodised aluminium construction
• Ready to install as a complete set

Pre-installation checks and preparation

Before fixing, ensure the roof opening is clean and free from debris, and that the window frame is square and level. Verify the opening dimensions match the 940mm × 980mm specification of this cover set. Check that the roof membrane or flashing around the window opening is in good condition and properly prepared. Have all fasteners and sealants to hand before you begin, and follow VELUX installation guidance for your specific roof type and pitch. The top flashing section should be positioned first to ensure water runs away from the window frame.

• Confirm opening dimensions are 940mm × 980mm
• Clean the window frame and surrounding roof area
• Check the roof membrane and existing flashing condition
• Install the top flashing section first for correct water drainage