How to Fit Shutters to Bullnose Corner Windows: A Guide
31st December 2019
3 min read
US - Trustpilot
Plantation shutters are straightforward to measure and install, even on windows with rounded bullnose corners. There are just a couple of extra things to consider when measuring and choosing your frame.
How to Measure Bullnose Windows for Shutters
The key difference with bullnose windows is where you take your measurement, and this depends on whether you're going inside or outside mount.
Inside mount: Measure at the narrowest part of the recess — the flat inside portion. If you measure at the front of the opening instead, the rounded corner will skew your measurement and the shutter may end up too large to fit inside the recess.
Outside mount: Measure to the widest part of the rounded edge, where it starts to turn flat, then add the width of your chosen shutter frame. This ensures the entire frame sits flush on the flat surface of the wall.
Choosing a Shutter Frame for Bullnose Windows
The right frame depends on whether you're mounting inside or outside the window recess.
Inside Mount: L-Frame or Z-Frame
Frame | What to Know |
|---|---|
L-Frame | Fits completely inside the recess. Mounted flush with the wall, you may need to caulk any gaps between the square frame and the rounded corner. Pushed back closer to the glass instead, it sits flush with the flat inner recess — but this may stop the panels opening a full 180 degrees. |
Z-Frame | Has an overlapping lip that surrounds the window opening. Choose a wide enough Z-Frame and it will cover the rounded edge entirely, hiding any gaps. Because the frame hugs the curve, screws may need to be drilled in at an angle. |
Outside Mount: L-Frame
An L-Frame will work well for outside mount, hiding the rounded edge once your shutter panels are closed. The key is making sure your measurements place the frame fully outside the rounded edge, sitting flat against the wall.
A Note on Drilling
Bullnose corners are often reinforced with metal. If you're drilling into the rounded area, you may need screws designed to penetrate metal rather than standard wood screws.
Still Have Questions?
Bullnose corners might seem like an unusual window shape, but we've seen them before — there's a straightforward solution for every case. Send a photo of your window to our shutter experts and we'll help you choose the right frame and measurements. Contact us by phone, email, or online chat.