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Security Bar Grilles for Windows

Securing Windows Using Bar Grilles
to Prevent Burglary

Security bar grilles, for windows, are a type of security grille that is usually comprised of vertical bars, passing through a horizontal strapping at a number of intervals that are determined by the height of the grille.

Bar grilles are usually permanently fixed solutions to securing a window, and are most commonly found in basement properties where the window is concealed from the public eye. Depending on how they’re constructed, they can offer the strongest solution for securing a property from break-ins. For this reason, insurance companies usually request security bars to be designed, manufactured and installed in accordance to their specification. This is most applicable when storing assets of a significant value – typically for commercial requirements.

Bars installed externally to the window offer a primary form of defence, making them the first point of attack. In the unfortunate event of an attempted break-in, this could prove advantageous in preserving the building from potential damage. When installed internally, they are less likely to interfere with the external features of the property – a common necessity for listed building requirements. Net curtains or blinds can also hide or lessen their view.

Development Life Cycle for Bar Grilles


Whilst potentially being the strongest type of grille available, this is largely dependant on the design. Security bars can be designed with innumerable options, each determined by building features and personal preference. We always make an effort to design each and every grille to match each individual window. This includes matching patterns within each grilles design to beading, transoms, or any other feature of the window, in an effort to blend with the window design by reducing any disproportionate or asymmetric appearance.

With external bar grilles, we often take advantage by using considerably heavier materials. We often design fixed bars to encompass an area for ventilation with opening windows. This is necessary when an opening window protrudes to the point where the grille is fixed. This is not usually the case for sash windows.

When designing internal grilles, we sometimes reduce the thickness of the material for aesthetic and habitable reasons.

The grille can be structured from decorative designs, or have small features between bars for a desired attraction. However, this can sometimes reduce the strength of the grille.

All bar grilles can be designed to include some functionality for removing or hinging them open, but this is not always the most practical solution to this problem. Collapsible Gates are most suitable for the frequent opening and closing of a security grille.


When installed externally, our standard design starts with 20mm solid round steel bars passing through 10mm thick solid steel flat strapping. Strapping is placed at a minimum of top and bottom. Sometimes it is necessary to place extra strapping at intervals to increase strength and prevent bars from being prized apart. This is necessary for grilles that are particularly tall in height.

Materials for internal grilles vary per job/opening, but we would usually start with 12 – 16mm solid square steel bars.


This sometimes makes it necessary to use large bolts for fixing the grille to the face of the building. All bolts are fitted with a round steel cap that is hit onto the bolt head to prevent them from being removed. When we fit bar grilles into the reveal of the opening (into the sides), we commonly use a method known as “pin and tube”. This is where a 20mm solid steel pin is hammered into the masonry, which can’t be pulled out.

The following video demonstrates the common fixing procedure into the reveal of the opening.

The installation procedure for bar grilles is generally quick.

Pricing Procedure

As with all grilles, the price of security mesh is dependant on the size of the job. We can provide you with a fast, accurate estimate if you provide us with dimensions of the opening/s over the phone, or filling out our contact page. Alternatively, we can send you out a surveyor to take measurements and give you a quote on site.