Window Restrictor Fitting and Replacement for Existing Windows

A window restrictor limits how far an opening window can swing or slide, usually to a gap too narrow for a small child to fall through, while still letting air in. They are commonly wanted on upstairs windows in family homes, rented flats, nurseries, schools and offices. Mark fits new restrictors to existing windows and replaces broken or missing ones, on uPVC, timber and aluminium frames. The window stays as it is; only the restrictor is added or renewed.

Restrictors fitted to existing windows
Broken or missing restrictors replaced
Suits uPVC, timber and aluminium frames
Fixed price confirmed before any work starts
Often same-day where the diary allows

There are a few common types. Cable restrictors use a short steel cable fixed between the sash and the frame, with a lock or release button so an adult can open the window fully, for cleaning or as a fire escape route. Catch-style restrictors are fitted into the frame and stop the sash at a set point until a release is pressed. Some friction hinges have a restricting stage built in. Mark advises on the type that suits your window and how the room is used.

Releasable restrictors matter in rooms where a window is an escape route. Fitting a restrictor that can't be released by an adult can block an emergency exit, so in bedrooms and similar rooms a releasable type is the usual choice. If you are unsure, it's worth checking the guidance that applies to your building before fitting.

On uPVC windows, restrictors are screwed into the sash and frame where the fixings will hold, avoiding the glass and the drainage slots. On timber windows they can be fitted to casements or, as sash stops, to sliding sash windows to limit how far the sash can lift. Aluminium frames need the right fixings for thin sections. Existing restrictors often fail because a cable has frayed, a lock has jammed or the screws have pulled out, and these are replaced like for like or with a sturdier type.

Landlords, letting agents, schools, nurseries and office managers often want restrictors checked and fitted across several windows at once. Mark can work through a building room by room and give one fixed price for the lot. For more on how we work with these clients, see our pages for landlords and for schools and nurseries. If a window won't shut or lock properly, our window lock repairs page covers that.

Replacing restrictors that have failed is just as important as fitting new ones. A frayed cable, a lock that no longer engages or a catch that has been forced will give a false sense of safety. Each window is tested after fitting so you can see it stop at the restricted gap and release properly, and you're shown how to use the release. Mark covers Central London and out to the M25, and you can send photos for a fixed price.

How the repair works

1. Tell us the windows Say how many windows, what they are made of and which floor, or send photos.
2. Fixed price You get a fixed price confirmed before any work starts.
3. Fit and test Restrictors fitted, each window opened to the restricted gap and the release checked.

Frequently asked questions

Do landlords have to fit window restrictors?

Landlords have a general duty to keep rented homes safe, and restrictors are widely used on upstairs windows to reduce the risk of falls. The exact requirements depend on the property and the guidance that applies, so it's worth checking for your building.

Can restrictors be fitted to uPVC windows?

Yes. Cable and catch restrictors are fitted to uPVC sashes and frames with fixings placed where they will hold, keeping clear of the glass and drainage.

Can a restricted window still be opened fully?

With a releasable restrictor, yes. An adult can unlock or release it to open the window fully, for cleaning or in an emergency.