How and where to use guide
VELUX GGL MK04 306621U Centre Pivot, Electric, Pine Lacquered, Triple Glazed 66 Pane Window, 78cm x 98cm
Typical applications and positioning
This MK04 size (78cm x 98cm) is suited to pitched roof installations in loft conversions, attic bedrooms, and upper-storey spaces where headroom or roof pitch limits conventional window options. The centre pivot design is particularly valuable in sloped roof applications where the window sits flush with the roof plane. Ensure the roof structure can support the window weight and that rafter spacing accommodates the frame width. Position the window to maximise daylight and ventilation without compromising roof structural integrity or creating thermal bridges at the installation point.
- Loft conversions and attic bedroom installations
- Pitched roof applications where standard windows are unsuitable
- Rooms requiring controlled natural ventilation and daylighting
- Positions accessible for electric operation and maintenance
Installation and weatherproofing
Proper installation is critical for performance and longevity. The window must be fitted with the manufacturer-supplied flashing kit appropriate to your roof covering (slate, tile, or sheet materials). The frame should be secured to the roof structure using the specified fixings, and all gaps sealed with appropriate sealant to prevent water ingress. Ensure the roof opening is accurately sized to the window dimensions and that the surrounding roof structure is sound. Poor installation will compromise the triple-glazing benefits and create damp problems. Consider engaging a qualified installer familiar with VELUX products for complex roof geometries.
- Use correct flashing kit for your roof covering type
- Seal all frame edges with weatherproof sealant
- Secure frame to roof structure with specified fixings
- Verify roof opening dimensions match window size precisely
- Check roof structure is sound and can support window weight
Operation and maintenance
The electric operation allows safe opening and closing from ground level, eliminating the need for ladders or reaching equipment in high roof positions. Use the supplied remote control or wall switch to operate the window smoothly. The centre pivot mechanism enables the sash to rotate approximately 90 degrees, allowing internal cleaning without external access and providing excellent cross-ventilation when fully open. Maintain the electric mechanism by keeping it free from debris and checking the battery or power supply regularly. Clean the triple-glazed panes with soft cloth and mild detergent; avoid abrasive cleaners that may damage the lacquered pine frame.
- Operate via remote control or wall switch for safe, convenient use
- Centre pivot allows internal cleaning without external access
- Rotate sash approximately 90 degrees for ventilation and maintenance
- Check electric mechanism and power supply regularly
- Clean glazing with soft cloth and mild detergent only
Performance and limitations
The triple-glazed construction provides superior thermal insulation and noise reduction compared to standard roof lights, reducing heat loss and condensation risk. The pine lacquered finish offers an attractive interior appearance but requires protection from direct water spray and excessive moisture during installation. Electric operation is dependent on mains power or battery supply; ensure a suitable power source is available at the installation point. The window is designed for pitched roof installation only and should not be used on flat roofs or in positions where water can pool. Avoid exposing the frame to prolonged direct water contact during construction work.
- Triple glazing delivers excellent thermal and acoustic performance
- Pine lacquered finish requires protection from water during installation
- Electric operation requires reliable power supply
- Designed for pitched roofs only, not suitable for flat roof applications
- Avoid water pooling or prolonged water contact on frame