Window security grilles

What are window security grilles?

A window security grille is a steel barrier fitted across a window so that breaking the glass no longer gives a way in. It can be retractable, fixed or removable, and is most often fitted inside the reveal where it is protected and barely noticed from outside.

Windows are the most common way into a building after doors, and ground-floor windows at the back of a property are the usual target because they are out of sight. A grille turns a pane of glass into something that takes tools, time and noise to get through.

The right type depends on how the window is used. A window you open every day suits a retractable grille that folds away. A window that never opens, such as a basement light or a rear storeroom, can take a fixed grille. Seasonal or rarely used windows can have a removable panel that lifts out of locked brackets.

How much do window security grilles cost?

Our guide range is £414 to £954 including VAT (£345 to £795 plus VAT) per window, supplied and fitted. The exact figure depends on size, type, finish and locking, and your fixed price is confirmed in writing after the free survey. See all grille prices.

Specification and options

Made to measure for the reveal, including bays and splayed reveals
Retractable, fixed or removable designs
Fitted inside the glass by default; external options for recessed or plain openings
Lock positioned to clear window handles and restrictors
Quick-release escape handle for bedroom and upstairs windows
Powder-coated in white, black or anthracite to sit with the frame colour
Anti-tamper fixings into masonry or a fabricated subframe
Works with uPVC, aluminium, timber and steel windows

Where window security grilles are used

Ground-floor and basement windows
Rear windows facing alleys and gardens
Flats with windows onto shared walkways
Offices and shops with side or rear windows
Outbuildings, workshops and garages with glazing

What to decide before you order

Retractable, fixed or removable

Match the grille to how often the window opens. Daily-use windows suit retractable; never-opened windows suit fixed; occasional windows suit removable.

Escape requirements

If the window is a designated escape window, the grille must open from inside without a key or tool. We fit quick-release locks for these.

Depth in the reveal

Tracks need a few centimetres of flat reveal. Where the frame sits flush with the wall, the grille can be fixed to a slim subframe instead.

Colour

White disappears against white frames, while black or anthracite suits darker frames and period sash windows.

Rules across the UK

The rules on planning, listed buildings and fire safety differ between England, Wales, Scotland and Northern Ireland. These are the points most relevant to window security grilles; local pages show the version for your nation.

England (similar principles apply in Wales, Scotland and NI)

Grilles inside the glass

A grille fitted inside the glass does not normally need planning permission, because it does not materially change how the building looks from outside. If the building is listed, listed building consent may still be needed.

Listed buildings and conservation areas

Listed buildings need listed building consent for works that affect their character, which can include internal grilles and their fixings. In conservation areas, councils look closely at anything fitted to the outside. We recommend speaking to the council's conservation officer before ordering.

Bedroom and escape windows

Approved Document B (fire safety) expects many habitable rooms in houses, especially first-floor rooms, to have an emergency escape window with an unobstructed opening of at least 0.33 m², at least 450 mm high and 450 mm wide, with the bottom of the opening no more than 1,100 mm above the floor. We only fit grilles over escape windows with a release that opens from inside without a key.

How it works

Tell us what needs securing

Use the quote tool or form, or call. Sizes and a couple of photos help us give a guide price straight away.

Free survey

A surveyor measures every opening, checks the walls and fixings, and talks through type, colour and locks.

Fixed price in writing

You get a written quote with the grille schedule, the price and the lead time. Nothing is ordered until you accept.

Made, fitted and handed over

Grilles are made to measure, fitted by installers working under our contract with you, tested and explained.

Window security grilles: questions

How much are window security grilles?

Most single windows fall between £345 and £795 plus VAT (£414 to £954 inc VAT) supplied and fitted for a retractable grille, with fixed bars from around £195 plus VAT (£234 inc VAT). Bay windows and large openings are priced at survey.

Should window grilles go inside or outside?

Inside in most cases. Internal grilles avoid weathering, are harder to attack, keep the outside of the building unchanged and rarely need planning permission. External grilles suit openings with no internal depth.

Can I still open the window with a grille fitted?

With a retractable or removable grille, yes. Many fixed internal grilles also leave room to open the sash or casement behind them.

Are window grilles safe in a bedroom?

They can be, provided the grille has a release that opens from inside without a key. Bedroom and upstairs windows often have to serve as escape routes, so we will not fit a key-only grille over a window you need for escape.

Do grilles work on bay windows?

Yes. A bay is usually treated as separate grilles for each face, or one grille following the bay on a curved or angled track.

Will a grille damage my window frame?

No. Grilles fix to the wall reveal or a subframe, not to the window itself, so the frame and its warranty are unaffected.

Find window security grilles near you

Choose your county or region for local information and the rules that apply where you are.

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