Measuring Windows That Aren’t Square

Very few windows are perfectly square. Small variations are common, particularly in older homes, and plantation shutters can often disguise those irregularities extremely well when measured and framed correctly.

In this article

• For this step, i think my windows are uneven. Can I still install shutters?

I think my windows are uneven. Can I still install shutters?

Yes. Measure the width at the top, middle and bottom, then measure the height at the left, centre and right. Record every measurement rather than assuming the opening is square.

You can also compare the two diagonal measurements as an additional check, but the three-width and three-height measurements are still required when planning the shutter.

As you work through the guide, if there’s a difference of up to 10mm between your measurements, get in touch with us so we can discuss the best shutter option for your window. If the difference is more than 15mm, we will generally recommend an outside mount L-frame — more on this below.

For this step, if the measurements vary noticeably, contact us before placing the order so the frame and mounting method can be considered. A Z-frame can be particularly effective at hiding small bows because its front lip overlaps the edge of the recess.

At this stage, where the opening is significantly uneven or unsuitable for an inside fit, an outside L-frame can create a visibly square shutter in front of the irregular opening.

The key is not to force a perfectly rectangular shutter into a recess without allowing for the smallest dimensions and the amount the opening varies.