Because many house break-ins are crimes of opportunity, it's not surprising that the common signal to strike is an unsecured window.

Vulnerability points

Windows are vulnerability points. Intruders choose to enter this way simply because windows tend to be left open or unlocked. An unclosed window visible from the street may be the sole reason your home is selected by a burglar.

As we know, many burglaries are crimes of opportunity. Ground floor windows are more susceptible to break-ins for obvious reasons. Upper floor windows are attractive if they can be accessed from a stairway, tree, fence, or by climbing on balconies.


Casement windows
  • Fit locks that secure the frames together in preference to locks that simply
    secure the handle or stay bar. There are also locks specifically designed for use on windows with tapered edges (not 90º to the frame).
  • If the window is flush with the frame, fit mortice rack bolts (bolts fitted into the window and operated from inside with a key). They should always be fitted at 90º to the grain of the wood, thereby reducing the chance of the wood splitting if forced.
  • It's possible to secure wooden casements open with mortice bolts for ventilation and child safety. These are particularly good for a ground floor bedroom where you want to sleep with the window open. Simply make a second locking hole at the appropriate opening distance. Then lock the windows open in the same way you would lock them closed.
  • If you are thinking of replacing your existing windows, make sure that they meet all of the necessary design codes.


Wooden sliding sash
  • You can't rely solely on existing central sash fasteners. Sash stops are strong
    and convenient to use and do not need to be removed from window when
     opening fully. They can be set into the top frame allowing the window to be left open for ventilation.
  • An alternative locking device is the dual screw. These effectively bolt the two
    sashes together. An added benefit is that they help reduce draughts.

  • You can fit extra locks to aluminium windows, but you need to make sure that there is enough metal around the window to be able to fit the lock without
    touching the glass.
  • With sliding horizontal aluminium windows, try fitting a key-operated clamp or patio bolt on the bottom rail of the frame. By fitting a sliding window lock to the bottom rail you can restrict the slide to a few centimetres.
  • Alternatively, you can drill a small hole through the bottom rail and insert an
    appropriate sized bolt. Drill the hole at the distance you want the window to
    open. In addition, to prevent the slider being lifted, fit a wooden block into the  track above the slider.


  • Louvre windows are becoming more common and while they are not very secure,there are some measures you can take to make them less vulnerable.

- Some are made with the glass secured in the frame. If not, fix the glass in the  frames with an epoxy resin adhesive.

- If the windows are sited in a vulnerable position, you may need to fit a grille or bars, though a better option may be complete replacement.

Leadlight windows

- Leaded panes are less common these days. They cannot be regarded as secure unless you fit secondary laminated glass, polycarbonate sheeting, or internal grilles.