Common Types of Window Locks
Over half of all home burglaries occur through a window and even the smallest one is vulnerable, so good locks are very important. The first line of defence is to fit key-operated locks to all ground floor windows, and those first floor windows that are easily accessible. It is also essential to provide secure ventilation around your home.
A wide range of locking devices for windows is available. Many are surface-mounted using screws and are quick and easy to fit, although for some types a drilled hole for a bolt or recess chiselled for a keeper plate may be required. Mortised locks and dual screws that fit into holes drilled in the window frame take longer to install, but they are very secure.
All window locks are supplied with fixing screws but these should often be discarded in favour of longer, more secure fixings. For extra security, it is also a good idea to fit two locks on casement windows more than 1 m (3ft) high and all locking devices for sash windows are best used in pairs.
For ventilation, if the window has a stay pierced with holes, you can replace the plain peg with a casement stay lock. Attach the screw-on lock to the threaded peg with the key supplied. You can now secure the window in position.
If fitting lockable window catches and stays, do not leave keys in the locks where they might be seen by an intruder or in case they fall out as the window is opened and closed. Instead, hang them on a hook close to the window.
Locks for wooden casement windows may be surface-mounted or set in the frame. In the former case, the lockplate is attached to the fixed frame and the body of the lock to the opening frame. With the window closed, mark the positions of the lock and plate on both frames, then screw them in place. For those with a locking bolt, you will have to cut a rebate (rabbet) or drill a hole to receive the bolt. Some surface-mounted locks are also suitable for metal casement windows. Check the instructions.
Locks that are set in the frame normally require holes to be drilled in both fixed and opening frames. Also, a hole must be drilled through the face of the frame for the key.
Some types of casement-window lock will also work with sash windows. Another option is key-operated dual screws, which bolt both sashes together. Use a flat bit the width of the lock barrel to drill through the inner meeting rail into the outer rail to the required depth, then tap the barrels into place with a hammer and piece of wood. Fit the longer barrel into the inner rail, the shorter into the outer rail, and screw the bolt into the barrel with the key.