My window is out of level and wonky

Have no fear, as not many windows are perfectly square and level, so you’re not alone. When fitting a square shutter frame into a wonky window recess, the frame does have to be smaller than the recess to allow it to fit.

This means there will be an uneven gap between the recess and shutter frame, but don’t worry as this is normal and it’s actually best not to fill this gap.

Why don’t you fill the gap?

Your wall, the shutter frame and filler will all be different colours and, depending on the size of the gap, the filler will eventually crack if it’s not been applied properly making it look messy.

Leaving a purposeful shadow gap is a much neater and professional way of finishing the shutters. The larger the gap, the less obvious it will be that the window is not quite square.

So, when choosing a design and fixing position for your shutter frame, always opt to install the shutter frame to your window where possible. This will make leaving a shadow gap much easier and will enable an easier, quicker and much neater fitting.

I am side fixing, do I need to fill the gap?

If, around your window, you have a plastic trim, large handles, air vents or something else that prevents you from fitting to the window frame, then you will have to side fix and fill the gap to hide the screws and packers between the wall and frame.

Leaving the right size gap is crucial and you will need to work this out depending on how out of level or square your window is. A large gap is hard to fill neatly and, if the gap is too tight, you may struggle to install the shutters properly.

Gap filling solutions…

Here are some options for filling gaps around shutters if your window is out of level.

  1. Use a shadow gap as your first option where possible.
  2. Decorators caulk, best used to fill small gaps.
  3. Fit the shutters towards the front of the recess and order some shutter trim.


When deciding which option will be best for you, it might be useful to watch the different fitting guides to see the end result.

Our video tutorial is free and you can get full access here.