Window locks - casement

Fitting locks to opening windows is a fundamental security measure which will make your windows less vulnerable to burglary and your property less attractive to potential thieves. You should of course buy good quality locks and position and fix them correctly. Whilst you should not leave the keys in the locks as this will make them next to useless, you and your family should know exactly where they are so that windows can be opened quickly in an emergency.

Window stay lock

A number of options are available for securing casement windows. The simplest device secures the window stay by means of a threaded bolt. A socket is screwed to the frame beneath one of the holes in the stay and the threaded bolt is screwed down through it using a simple key. Obviously there are numerous types available but the principle is the same. The casement stay is fastened to the frame with the threaded bolt mechanism. If needs be, you can remove one of the original pins for the stay and replace it with the bolted one.

Window swing lock

The second option is a window swing lock. These comprise two pieces - a lock plate and a lock body. The plate is a T shaped section which is fitted to the frame usually mid way between the top and bottom. For larger windows it will be necessary to fit two of these locks at equal distances. The plate is screwed to the frame and set about 1mm back from the closing edge

The body is a D shape section which is mounted on the opening frame in line with the plate so that when the window is closed, it can be swung over the lock plate and fastened using a key. To fit this part, with the window in the closed position, hold it in its opened position with the fixing points either side of the lock plate lug. Mark the holes and remove. Pre bore the holes with a bradawl to get them started them hold the lock body in position and fasten with the screws provided

Window snap lock

These are similar to the swing lock except that the lock plate is mounted on the opening part and the body on the frame. As the window is shut, the lock plate lug goes into the body and locks automatically. A key is then required to open

Security bolts

Security bolts mounted in the edge of the frame may also be used for large windows. Fitting these is the same as for doors

• Window locks - sliding sash
• Windows - casement repairs