Measuring for Outside Recess
This is the measurement you need to take if you want your roman blind to fit outside the recess of your window.
Use a metal tape measure, cloth ones can stretch and give inaccurate measurements.
If you are measuring for bay windows, I would recommend sending me a photo so I can see the configuration of the windows - whether it’s a square bay or angled - as specific amounts have to be deducted from the corners to make sure the tracks will fit. I can send you markings on where to measure.
If it is a sash window with an architrave around the recess, again, I would send a photo of your window so I can tell you where to attach the track and measure.
Measure the exact width of the area you would like the blind to overlap. To minimize light leakage we recommend that the blind overlaps the window recess by at least 5cms each side, but this can of course be less or more if you wish.
For the drop, the overlap at the top of the window recess needs to be at least 5cms to allow for the track.
If there is a windowsill then the blind normally rests on this.
If you would like to send me a photo of your window please do so if you would like me to check for you if unsure.