Deciding Between Installing Window Bars & Grilles Inside or Outside: Factors to Consider for Your Property

retractable security grilles

If you a looking for a specialist in security grilles for doors and windows installation in North London we have the professional expertise you need to make the best decisions from a security and aesthetics perspective.

When deciding whether to install window bars inside or outside you need to consider what is possible as well as personal preference. In this blog post we delve deeper into necessary considerations when choosing whether to fit window grilles outside or inside.

Factors Which Determine Whether You Can Install Window Grilles Inside or Outside

When planning bespoke window security bars installation we aim to balance customer preference, practicalities and the configuration of each individual property to produce the perfect solution for each property.

External Collapsible security grilles
External Collapsible Window Security Grilles Due to Difficulty Reaching The Window Internally

There are some important factors that determine if a window grille would be best fitted outside or inside a property. These are key points we will consider when carrying out an initial survey to plan custom design security grilles.

1) Are your Windows outward or inward opening?

Outward Opening Windows

If your windows open outward it makes sense to fit window grilles on the inside so the the windows can open outwards, and for several other reasons.

Inward Opening Windows

If your windows open inwards and you would like fixed window bars then you will need to install the security grilles on the outside of the window to ensure that the windows can be opened.

Likewise, if you would like collapsible security grilles installed it makes sense to fit them on the outside so that you can open the windows when the grilles are in the locked or open position

2) What Floor are the Windows On?

On upper levels we would generally fit fixed and collapsible grilles on the inside due to health and safety. Whilst we would install them externally, we would require the appropriate scaffolding in place.

Collapsible grilles on a upper levels can not be easily opened and closed unless they are installed on a patio door with a Juliet balcony. This is why external window bars on higher level windows generally tend to be fixed as opposed to retractable.

If your windows are on an upper level then you may want to consider that there will be an additional cost due to scaffolding required.

Customers often ask us if we can save on scaffolding costs by carrying heavy metal window grilles up a ladder. This is not an option for practical and safety reasons because it is quite often a 2 person job and involves accurate positioning and precision work to achieve the best result.

3) Where can the Best Possible Fixing be Achieved?

We will assess the property to establish where the best window grilles fixings can be achieved. This will depend on the space available around the window and if there are any obstructions in the way such as pipes, guttering or other obstacles to work around.

External Burglar Bars and Internal Retractable Grilles on a Patio Door
External Burglar Bars and Internal Retractable Grilles on a Patio Door

As Security Grilles Specialists We Advise Installing Window Grilles Inside Where Possible

There are several reasons why we advise clients to install grilles inside windows as opposed to outside. Burglar bars inside or outside both provide high levels of security when carefully planned and installed by an experienced professional. However, there are some differences it is good to be aware of in the planning.

The Advantages of Installing Window Grilles Inside a Property

a) Internal Security Bars are Generally Cheaper

The cost difference between internal and external security grilles is significant. There are 3 reasons why internal window bars cost less than bars fitted on the outside of windows;

  1. The thickness of the bars required to achieve optimum security is less than when fitted on the outside – We usually fit 12mm square bars internally and 16mm or 20mm window bars on the outside.
  2. Internal bars don’t need to be galvanised – External bars can be galvanised to give extra protection from the elements
  3. Chemical fixings are not required for window bars on the inside – Internal fixings are not as easy access to intruders as they are when fitted on the outside of the property. Adding chemical fixings to external bars adds to the costs and has the added disadvantage of potential damage to the finish of the security grilles during the fitting process which needs to be factored into the costings.

b) Window Bars Inside Don’t Get as Dirty and Weather Beaten

Adverse weather not only increases the likelihood of rust but the security bars are more likely to become weathered and dirty on the outside. Generally, it is much easier to maintain the condition of internal security bars as they are not directly subjected to extreme weather and external factors.

c) Internal Security Bars Can Be More Secure

When security bars are fitted on the inside of windows the actual bars and the fixings are less accessible to intruders. When window bars are on the outside the bars and fixings are more vulnerable we need to use thicker bars and chemical fixings to secure the bolts.

c) Window Bars on the Inside Can be Removed More Easily for Decorating

If you did want to remove the window bars for decorating or any other reason it would be much easier because we would not have to use specialist security fixings.

d) It is Easier to Open and Close Collapsible Window Grilles When They are Installed on the Inside

Easy access to the security grilles from the inside of the property at any time of day and in any weather is very convenient.

The final design decisions will depend primarily on the configuration and location of the individual property teamed with the client’s personal preferences.

window bars installed on the inside with colour matching the interior
Invisible Window Bars Inside and Colour Matched to the Interior

Personal Preferences in Installing Window Bars Inside or Outside

If the configuration of the property allows you to install a window grille outside or inside we will make the client fully aware of the pros and cons of installing window grilles both internally and or externally. After that, it will be a matter of what works best for you in terms of the look and convenience of using the security grilles.

Collapsible Security Grilles Installed Inside
Collapsible Security Grilles Installed Inside a Bay Window

Professional Advice on Installing Window Grilles Inside or Outside

At IKS we have expertise in retractable or folding security grilles for windows and fixed security grilles installation. Our experts can provide you with professional advice on whether your window grilles should be outside or inside based on years of experience. We have completed a wide range of custom design projects on different types of properties from modern to period homes and businesses.

Visit Our Security Grilles Gallery for Design Ideas

You can see examples of projects that show the visual difference between internal and external grilles by visiting our Security Grilles Gallery. Look out for window bars that blend seamlessly with the original windows, as invisible window grilles design specialists we are always keen on a design challenge! You may also like to read our blog post about designing Types of Security Grilles That Don’t Look Ugly.

As experienced experts, we can help you design the best window grilles inside or outside. Contact us for professional security advice on securing your home or business in London and the surrounding area.

How can we help you?

For professional security advice and information call to speak directly to Martin, our Master Locksmith and security specialist.

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Master Locksmiths Association



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  • IKS Locksmiths Ltd
    Unit E2,
    Queens Rd,
    Barnet EN5 4DJ
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