Fixing and buying guide
VELUX Support Trimmer for 18mm Frame Gap - White Roof Windows EBY W27 2000
What this product is and who needs it
This is a support trimmer that fills and seals the 18mm gap created between a VELUX EBY W27 2000 roof window frame and the surrounding roof structure. It prevents water ingress, dust, and draughts whilst providing a finished appearance. You need this product if you are installing or replacing a VELUX EBY W27 2000 white roof window and have an 18mm frame gap to seal.
- Designed for VELUX EBY W27 2000 models only
- Fills 18mm gaps between window frame and timber
- Creates weather-tight seal to prevent water and air leakage
- Provides neat, finished appearance around window installation
Compatibility and sizing
This trimmer is compatible with timber grades F16, F24, and F36, covering the full range of standard structural timber used in UK roof construction. The 18mm frame gap specification is fixed, so you must measure your actual gap before ordering to ensure this is the correct size for your installation. If your gap is larger or smaller, a different trimmer size will be required.
- Compatible with timber grades F16, F24, and F36
- Fits only 18mm frame gaps
- Measure your frame gap before purchase to confirm compatibility
- Not suitable for gaps larger or smaller than 18mm
Installation and preparation
Before fitting, ensure the roof window frame is correctly positioned and level. The trimmer is designed for installation in tight spaces where standard trimmers cannot reach, so its compact design allows manoeuvrability in confined areas. The white plastic construction is durable and requires no special preparation or treatment before installation. Ensure the gap is clean and free from debris before inserting the trimmer to achieve a proper weather-tight seal.
- Ensure roof window frame is level and correctly positioned before fitting
- Clean the 18mm gap of any debris, dust, or old sealant
- Compact design allows installation in confined roof spaces
- No pre-treatment or preparation of the trimmer required
Pre-installation checks
Confirm that you have the correct VELUX model (EBY W27 2000) and that your frame gap measures exactly 18mm. Check that your surrounding timber is one of the compatible grades (F16, F24, or F36). Inspect the trimmer on delivery for any damage to the white plastic, as this could compromise the weather-tight seal. Ensure you have adequate access to the roof window installation area and that the window frame is fully secured before fitting the trimmer.
- Verify you have VELUX EBY W27 2000 model
- Measure frame gap to confirm it is 18mm
- Check surrounding timber grade is F16, F24, or F36
- Inspect trimmer for damage on delivery
- Confirm roof window frame is fully secured before fitting