Your Guide to Measuring & Specifying Security Grilles

Please note that if you order security grilles for DIY fixing, we will accept your order on the understanding that you have checked your measurements and are happy with them. As these products are custom built, once your order has been processed for production there can be no amendment or cancellation.

We do offer a professional security fitting service. If you are not confident that you can measure up accurately, or you just want the peace of mind of knowing that your grilles are guaranteed to fit it is worth considering this option.

Points covered in this guide
Click on the links below to jump straight to the part of this guide you are interested in

  • Measuring up your grille. How do you want to fix your grille to the area it protects? Where exactly do you need to take your measurements from?
  • Clear opening width and stack sizes. Will the opening in your security grille be large enough? How much room will the stacks at either side take up once they are closed?
  • Lattices and Posts. How exactly will your security grille look? How many posts and lattices will be used to make it up, and what are my lattice pattern options?
  • Additional Sash Options. Need a fixed security grille? Need better access for cleaning? Don't have suitable fixing points above your grille to take the weight? These options may help.
  • Bottom Track Options. Need a totally clear floor when your grille is open? Need to reduce the trip hazard of your grille's standard bottom track? These options will help.
  • Hinge Aside Option. Need to fold your security grille away when it is not locked for aesthetics or better clear opening width? Then you need the 'hinge aside' option.

Measuring up your grille

Diagram, showing the difference between face and reveal fixing

All Simply Shutters security grilles can be reveal fixed (fitted inside an opening) or they can be face fixed. The difference between the two methods is shown below. It is possible to mix these options as shown in the first diagram.


reveal fixing, order the grille 5mm less than the width and height of the opening.

For face fixing, the drawings below show the optimum position. However it is best to position grilles so that the fixings go into solid material or that the stack is concealed behind a wall, and this will affect grille sizes. Please ask for advice if in doubt.

Measuring up for a single sash Citadel Security Grille. Shown with folding track

Note that if you need to determine your own fixing points on site we can drill grilles for face and reveal fixing and we can also leave them undrilled by special request. Contact us to order if you need either of these options.

For single sash security grilles you should include the slam post width in your measurement. You simply need to measure the overall width and height of the grille before ordering. All other options added will fit inside these dimensions.

You should always take three measurements for the grille width (at the top, middle and bottom of the grille) and you should also always take three measurements for the grille height (left hand side, middle and right hand side).

You should then order using the shortest width and height.

Many windows and doors are not square, and this will ensure that your grille will fit the opening you are ordering for.

Clear opening width and stack sizes

The clear opening width and stack size(s) for a security grille depend on overall grille width, and also whether you require folding bottom tracks or the hinge aside option. Click here for more details.

Lattices and Posts

Measuring up for a double sash Citadel Security Grille

The number of lattices used to make up your security grille with depend on the grille height. The grille lock can also be optionally changed to a position dependent on the number of lattices used.

The number of posts used to make up your grille will depend on the grille width.

See the diagrams and tables below to work out how many posts and lattices will be used to make up your grille.

Basic component parts of a Citadel Security Grille (reveal fixed)

Additional Sash Options

In addition to the single or double retractable grille options mentioned for the Citadel range above, we can also offer the following:

Lattice and lock configurations for Citadel Security Grilles

Bottom Track Options

Citadel security grilles can be supplied with the options shown in the diagram below as alternatives to the standard low profile fixed bottom track. Folding and lift out tracks are useful when clear access is required, and to reduce the trip hazard of a standard bottom track.

Additional Sash options for the Citadel Security Grille

Hinge Aside Option

This option is not available for our insurance certified grilles, Citadel Plus Home or Citadel Plus Commercial.

The hinge aside option allows a whole sash to be folded back once it has been closed (for double sash grilles, each sash folds back independen -tly on its own side). This is useful for aesthetic purposes, or to increase the clear opening width of the grille.

The Citadel Hinge Aside option
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If you can't see the information you need in this guide, please give us a call on 01842 814260. We are always happy to help.
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