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 midway 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 them. 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 mounted on the edge of the frame may also be used for large windows. Fitting these is the same as for doors
Window locks – sliding sash
Good quality locks fitted to all windows are an important safeguard for the overall security of your home. They are simple to fit and the time taken is well worthwhile. As with all key-operated locks, do not leave the key in them or on display but do make sure all members of the household know exactly where they are in case of emergency.
Sliding sash window lock
The most usual and very effective type of lock for sliding sashes is the dual screw. A metal barrel is inserted into the inner sash and either another metal barrel or a lock plate fitted to the outer sash. The bolt is inserted and screwed into place using a key
Fitting the dual screw lock
It is usual to fit two of these locks on sliding sash windows unless they are small. With the window in the closed position, mark the position of each lock on the horizontal rail of the inner sash. Then mark the halfway point between the top and bottom of this rail at these positions. Before drilling, double-check that the hole will not catch and crack the edge of the glass. If needs be, offset the lock slightly to clear the glass.
Using a drill bit of the recommended diameter, drill into the inner sash and on into the horizontal rail of the outer sash. The depth of the hole in the outer sash will be detailed with the lock, but this will usually be around 18mm. In order to avoid over drilling, use a depth gauge mounted on the drill and set to the required overall depth. If you don’t have one of these, simply wrap a small piece of tape around the drill bit at the right depth and stop when the tape reaches the surface. Open the sashes and clean out all the residual sawdust. A vacuum cleaner does an excellent job of clearing this.
Insert the barrel for the inner sash into the hole and tap it home so that it is flush with the surface. Use a small block of wood on it so as to prevent damage from the hammer. Some windows – particularly older ones with thinner glass can be quite fragile. For these, you can push the barrel into the sash by holding a clamp around the two and tightening it till the barrel sits flush. Repeat the process with the outer shorter barrel
Close the window sashes and insert the bolt into the barrels and use the key provided to secure it. Depending upon the lock and the window sizes, it may be necessary to shorten the bolt. This can easily be done by holding the bolt in a bench vice and trimming with a hacksaw.
Sash window push lock
These are very simple devices consisting of two surface-mounted metal plates with a push-lock mechanism between the two and requiring a key to release. Fitting is very straightforward. Simply hold the two sections together in the locked position and place on the horizontal rails where the two sashes meet making sure that the dividing line between the two aligns with the meeting line of the inner and outer sash.
The plates are then simply screwed into the sashes using the screws provided. This type of lock is a little less secure as the screws are visible making them easier to remove. However, they are quicker and easier to lock and unlock than the dual screw bolt and afford a reasonable degree of security.