Securing The Main Entrance To Your Home Or Business
Although most break-ins are, as we have seen, at the rear and through a window, some are made through front doors if they look likely to yield without too much trouble.
The average lock used on most front doors is one of the easiest things to open by even a semi-skilled thief. It can be sprung open by means of a thin piece of plastic such as a credit card pushed against the latch on the door and frame – an alternative criminal use of the credit card! If the door has a glass or thin wooden panel near the lock, it can be broken and the hand inserted to turn the lock from the inside.
Many locks have the staple (the part of the frame that the bolt engages with) fixed by short screws into the wood. A shoulder charge or levering with a jemmy can easily loosen the ease and forced them out.
Any such conventional locks or spring latches as they are more accurately termed, should be immediately replaced with a deadlock. This is a lock with a bolt that cannot be retracted without a key, that is one that you cannot slam shut but must be locked with a key when leaving. It cannot be sprung open with a card; nor can be opened from the inside without the key. Thus preventing the front door being used as an exit route.
Most spring-latches have a two-lever mechanism and, if other means of opening them fail, can be picked without too much trouble. Security deadlocks have a minimum of five levers; some have up to 10 levers and are virtually impossible to pick. Another desirable feature is the provision of steel rollers set inside the bolt: any attempt to saw through with a hacksaw is then futile.
It is generally held that a mortice lock, i.e. one that is fitted in the door rather than screwed to its surface, offers the greatest security. This is because it cannot be removed from the inside by an intruder who has gained access at some other point and wishes to establish an exit route; nor can it be burst off the door by force.
However, this needs qualification. Wood has to be removed from the door to make a cavity in the order to fit the lock. Thus the door is weakened at that point. If the door is thin, as many modern ones are, there may only be a thin shell of wood enclosing the lock. The application of force could splinter the wood away, rendering the door lock useless. In addition, the staple is let into the door frame, and the same weakness could exist there if the frame is insubstantial. So rather than improving security, a mortice lock could considerably reduce it.
Some modern mortice locks are made especially thin to overcome this problem, and less wood has to be excavated. Even so, for a thin door, the value of a mortice lock is dubious. It could be added that a thin door in itself is a security hazard and should really be replaced by something more substantial.
If there is some doubt about the matter it would be better to fit security surface lock such as a deadlock, which offers better protection. Bolts from the key plate at the front of the door pass rate through the door to the lock on the back, and which woodscrews enter the doors sideways through the side flange in some models. The lock is thus impossible to remove from the outside or inside while the door is closed. As it exerts a clamping effect on the door, it strengthens rather than weakens it. An attempt at forcing an entry is thus unlikely to succeed. The staple is also secured by sideways screws which are concealed when the door is closed and will resist a considerable amount of force.
The type of dead latch illustrated does not need to be locked shut but can be slammed just like a spring latch, and so is more convenient when leaving. However, the shape of the latch and its action make it very difficult to spring open with a card. Another feature is the double locking facility. The lock has a keyhole on the inside as well as the outside. When the inside is locked the hand lever is immobilised so that it cannot be operated to open from the inside. The surface deadlatch is thus really preferable to the mortice lock, although the latter has the reputation being more secure.
It should be noted that the key of a mortice lock should always be left in the lock at night and a deadlatch should not double be double locked at night. This is in case of fire. Intruder security measures should never jeopardise a fire escape route; better be burgled than burnt.
Often expensive locks are installed on a stout door, but the door frame is thin and so forms the weak link. The door may remain intact after a hefty charge, but the frame may splinter, so rendering all the security devices useless. The frame must, therefore, be critically examined.
One trick that has been used by burglars is to spring the door frame apart with a carjack at the point where the lock is fitted. Often it can be bowed sufficiently to disengage the lock bolt from the staple or rebate plate. To minimise this possibility the frame should have a solid support at the sides. Weak materials such as plaster should be excavated and replaced with concrete on both sides of the door, especially near the locks, and any gaps should be filled with the same material. The rebate itself should not be less than three-quarters of an inch (20mm) thick.
Further security can be achieved by having to locks spaced well apart. This adds to the inconvenience of locking and then unlocking and means an extra key; it is one of those decisions that have to be made as to the degree of security considered necessary. In high crime areas or if valuables are kept in the house, it would be advisable.
Where are very high security is required, even a stout wooden door may be insufficient. Battering rams have been used to break down doors. A wooden door can be reinforced by covering the outside surface with mild steel of 16 gauge or thicker. The edge should be turned over and secured to all four door edges by rows of countersunk wood screws.
In addition, coach bolts should be fitted at intervals of not more than 9 inches, with the heads on the outside, and passing through the styles and rails (the main vertical and horizontal door members). On the inside, large washers should be fitted underneath the nuts, and the bolt ends should be burred over the nuts.
A good quality mortice deadlock of at least five levers should be fitted, together with mortice lockable bolts if the door is not to be used as the final exit. If it is, then at least one other similar lock should be fitted. Then increased weight will require an extra pair of hinges, and dog bolts should be also fitted on the hinge side.
This will give an extremely attack-resistant door, but do not overlook the frame, which could now be the weak link. As before, it must be well supported by concrete at the sides. In addition, a strip of angle iron screwed to the frame at the opening side prevents the insertion of a jemmy to force the door and frame apart. It may need hardly be added that such a measure is not usually necessary for a domestic front door. It has been described for cases where special security may be required.
For more help and advice on securing your home or business, call IFire UK Ltd on 0330 121 1234