Measuring an Inside Mount Window with a Sill
A sill changes the bottom reference point for an inside-mounted shutter, especially when the sill projects or slopes.
Check your recess depth before measuring
As a clear guide, allow approximately 70mm of clear recess depth for an inside-mounted plantation shutter. Confirm the shallowest usable depth and measure to the first obstruction that could interfere with the shutter, including a handle, winder, lock, key, flyscreen or other window fitting.
Where the opening has around 70mm or more of clear space, you can typically proceed with the inside-mount measuring instructions.
Have less than 70mm, or an obstruction in the recess? An inside mount may still be possible based on the frame choice and where the obstruction sits. See our Managing Window Obstructions guide for the detailed clearance requirements.
Measuring Inside Mount for a Square-Set Window with a Sill
- Measure the drop in three places from the top surface of the sill to the inside top of the recess.
- Measure the width in three places inside the recess.
- Use the smallest width and smallest drop.
Measuring Inside Mount for a Window with a Sill and Architrave
- Measure the drop in three places from the top of the sill to the inside top of the recess.
- Measure the width in three places inside the recess.
- Use the smallest width and smallest drop.
Prior to releasing the order: if your recess is less than approximately 70mm deep, or incorporates handles, winders, locks, flyscreens or other obstructions, check our Managing Window Obstructions guide before finalising your inside-mount dimensions.
Did this answer the job question?
Related articles
Need trade support?
Send our trade team the window opening dimensions and photos if anything is unclear about the right shutter setup.
