How and where to use guide
VELUX Support Trimmer for 18mm Frame Gap - Pine Roof Windows EBY W20 3000
Typical applications and installation
This support trimmer is used during the installation of VELUX EBY W20 pine roof windows to bridge and seal the 18mm frame gap between the window frame and the surrounding roof structure. The trimmer sits within this gap, providing structural support and helping to create a watertight seal that protects against water penetration. The 3000mm length is suitable for standard roof window installations and can be cut to length as required for your specific opening. Installation typically involves positioning the trimmer within the frame gap before final window seating and securing, working in conjunction with the window frame itself.
- Position the trimmer within the 18mm frame gap during window installation
- Ensure the trimmer sits flush and level to support the window frame evenly
- Cut to length as needed for your specific roof opening dimensions
- Use alongside appropriate flashing and sealing products for complete watertight installation
- Suitable for pitched roof installations with VELUX EBY W20 windows
Working with the material on site
The pine construction of this support trimmer makes it straightforward to work with on site. Pine can be easily cut with standard hand saws or power saws to fit your exact requirements, and it accepts fixings readily without pre-drilling in most cases. The compact design allows the trimmer to be positioned in confined roof spaces where larger timber sections would be difficult to manoeuvre. Handle the timber carefully to avoid splitting, particularly at the ends, and store it in dry conditions before installation to prevent moisture-related movement.
- Cut to length using a sharp saw for clean edges
- Protect cut ends from moisture exposure before installation
- Work in dry conditions where possible to minimise timber movement
- Support the trimmer adequately during installation to prevent sagging
- Ensure the trimmer remains level and true within the frame gap
Watertightness and sealing
The primary function of this support trimmer is to help establish a watertight seal around the window frame. The trimmer fills the 18mm gap, reducing the void that water could penetrate. However, the trimmer alone does not create a complete watertight installation. You must use appropriate flashing, membranes, and sealants in conjunction with this trimmer to achieve full weather protection. Pay particular attention to the junction between the trimmer and the window frame, and between the trimmer and the roof structure, ensuring these areas are properly sealed with suitable products.
- Use in combination with VELUX flashing and sealing products
- Seal all gaps between trimmer and frame with appropriate sealant
- Ensure flashing overlaps correctly to direct water away from the frame
- Check for gaps or movement after installation and reseal if necessary
Limitations and compatibility
This support trimmer is designed specifically for VELUX EBY W20 pine roof windows with an 18mm frame gap. It is not suitable for other window types or different frame gap sizes. The 3000mm length is a standard supply length and may require cutting for smaller openings or joining for larger installations. As a support component, it must be used as part of a complete installation system including proper flashing, membranes, and sealants. Do not rely on this trimmer alone to provide weatherproofing.
- Compatible only with VELUX EBY W20 pine roof windows
- Designed for 18mm frame gaps only
- Must be used with appropriate flashing and sealing products
- Not a standalone weatherproofing solution