Managing Obstructions

Obstructions could be inward opening windows or fly screens, which may not be accessible if you inside mount your shutter. Other obstructions, such as window winders, handles, locks, keys, alarm boxes are fine - as long as you have enough clearance between the end of your obstruction to the end of the recess.

Even with a deep recess, your window may have obstructions that could get in the way of inside mounting your shutters; but there are ways around this!

In this article:

• How to get around an obstruction
• Managing obstructions for a Z-frame
• Managing obstructions for an L-frame

How Much Clearance Do I Need For An Inside Mount?

As a general rule, 70mm of clearance is required from the furthest point on your window to the edge of the recess for inside mounting. This is so that the shutter blades can be opened completely without hitting the window pane. However, this requirement is relatively conservative and the exact clearance needed ultimately depends on the type of frame you will be using. 

In other words, You may still be able to Inside Mount your shutter, even if you have less than 70mm between your obstruction and recess. To learn more, read our article on Measuring for a Recess.

How Do I Get Around An Obstruction?

To begin with, it's important to differentiate between the shutter panels and the frame itself. The frame will create a border around the inside of your window recess, while the shutters will hinge inside the frame.

The shutters sit inside the grooves of the frame, and therefore require less depth to be mounted. However, we need extra clearance for the louvers (shutter blades) to fully open. In other words, there are various measurements that need to be taken into account, depending on where the obstructions sits on the window.

Managing Obstructions For A Z-Frame

A Z-frame mounts inside the recess and creates a lip around the outer frame. A Z-frame requires 39mm of clearance to fit inside the recess.

Obstructions On The Outer-Edges Of Your Window Recess

If your obstruction is on the very bottom, top or sides of your window (i.e. up to 29mm from the recess), you will need to measure from the obstruction to the edge of the recess. If you have 39mm of clearance, you will be able to mount a Z-frame. Keep in mind, frames won't open once installed so you may want to allow for an extra few millimetres in order to access obstructions!

Obstructions Located Towards The Top Or Bottom Of Your Window Recess

If your obstruction is located at the bottom or top of your window, but beyond where the frame is mounted (i.e. further than 29mm from the bottom/top of the recess), we need to consider bottom and top rails. Bottom and top rails look like shutter louvers, but don't open and close. To fully clear (and access) obstructions behind bottom or top rails, you must have at least 20mm of depth.

Obstructions Located Towards The Centre Of The Window

Bottom and top rails are generally between 85mm and 148mm in height. If your obstruction is located 114mm from the bottom or top of your recess, you need to consider whether your blades will open properly.

If your obstruction is located further towards the centre of the window, you need to be sure that louvers (shutter blades) will open fully without hitting the obstructions. You must have 55mm of clearance to ensure that louvers can be fully opened. You won't need to worry about accessing obstructions, as shutter panels can be opened to reach winders, handles or keys. 

If you don't have 55mm clearance to allow for louvres to open, you can always add a midrail to your shutters. Since midrails don't open, you will only need 20mm to clear the obstruction. The same rules apply here as top or bottom rails (see above), only in the centre of your window.

Obstructions On The Sides Of Your Window Recess

If your obstruction is on the side of the window, but beyond where the frame is mounted (i.e. 29mm - 70mm from either the side of the recess), then you must have 20mm of clearance. However, if your obstruction is more than 70mm from the side of the wall, you will need to be aware of louvres opening (see above).

Summary: Managing Obstructions For An Inside Z-Frame

To learn more, read our article on Z-frames

Managing Obstructions For An L-Frame

An L-frame fits inside the recess and can be mounted flush against the wall or sit back from the wall at any desired depth. An L-frame requires 65mm of clearance to fit inside the recess.

Obstructions On Outer-Edges Of Your Window Recess

If your obstruction is on the very bottom, top or sides of your window (i.e. up to 35mm from the recess), you will need to measure from the obstruction to the edge of the recess. If you have 65mm of clearance, you will be able to mount an L-frame. Keep in mind, frames won't open once installed so you may want to allow for an extra few millimetres in order to access obstructions!

Obstructions Located Towards The Bottom Or Top Of Your Window Recess

If your obstruction is located at the bottom or top of your window, but beyond where the frame is mounted (i.e. further than 35mm from the bottom/top of the recess), we need to consider bottom and top rails. Bottom and top rails look like shutter louvers, but don't open and close. To clear (and access) obstructions behind top or bottom rails, you must have at least 29mm of depth.

Obstructions Located Towards The Centre Of Your Window

Bottom and top rails are generally between 85mm - 148mm in height. If your obstruction is located 150mm from the bottom or top of your recess, you will need to consider whether your blades will open properly (see below).

If your obstruction is located further towards the centre of the window, you need to be sure that louvers (shutter blades) will open fully without hitting the obstructions. You must have 65mm of clearance to ensure that louvers can be full opened. You don't need to worry about accessing obstructions, as shutter panels can be opened to reach winders, handles or keys.

If you don't have 65mm clearance to allow for blades to open, you can always add a midrail to your shutters. Since midrails don't open like blades, you will only need 29mm to clear the obstruction. The same rules apply here as top or bottom rails (see above), only in the centre of your window.

Obstructions Located On The Sides Of Your Window Recess

If your obstruction is on the side of the window, but beyond where the frame is mounted (i.e. further than 35mm from either the side of the recess), then you must have 29mm of clearance. However, if your obstruction is more than 78mm from the side of the wall, you will need to be aware of louvres opening (see above).

Summary: Managing Obstructions For An Inside L-Frame

To learn more, read our article on L-Frames.

If you're still unsure, send us a photo of your window and our team will take a look!