The Crime Prevention Website


Frame reinforcement bars

During my time on the beat I attended quite a number of burglaries where the entrance door had been kicked/barged so damned hard that either the mortice lock came clean out of the door and ended up at the end of the hall or the door frame split or both.  Most of the doors that experienced this type of force tended to be deeply recessed ones or were internal private flat entrance doors.  In all cases the burglar would have been hidden from view and that’s not surprising considering how much energy was expended.  To make it more difficult for this type of burglary to take place you can fit reinforcing bars to the doorframes and, as you will see in the next but one paragraph, mortice lock reinforcing kits around the door locks.

The reinforcing bars are called ‘London Bars’ when fitted on the locking side of the door frame.  These have a small bend in them to go around the nightlatch keep.  When fitted to the doorframe on the hinge side they are called ‘Birmingham Bars’.  They clearly do things differently in Birmingham.  These bars of quite thick flat steel are usually painted white and are fixed at intervals of about 300mm. The idea behind them is that they will help to spread the force along the length of the frame and thus reduce the chance of splitting.  Unfortunately the burglar won’t know they are there and so you can still expect some damage.  Hopefully, though, they will buy you time and may make the burglar give up.

Mortice lock reinforcing kit

Great care must be taken when fitting a mortice lock, because although you are replacing the lost wood with the lock case, if the lock case is at all loose in the mortice it will act as an internal lever when the door is kicked or barged.  This may result in the door splitting around the lock and the lock flying out of the door. 

To avoid this from happening it is useful to fit a mortice lock reinforcing kit.  In essence the kit consists of two metal plates that are bolted to each other through the door and which sandwich the lock and door together.  Their purpose is to help prevent the door from splitting and to hold the lock into the door.  Unlike the reinforcing bars at least this additional security can be seen by the burglar. 

If your door is a private flat entrance door or is recessed or you live in an area that has an average or higher risk of burglary these are well worth fitting and are normally a DIY job.  That said, reinforcing plates may affect the performance of a fire resistant door so you should seek expert advice from a member of the Master Locksmiths Association if you have one of these.