Home Security: Securing Doors
Ira A. Lipman
The easiest way for someone to enter your home is simply to
open an unlocked door. In fact, this is the way that many houses are illegally entered.
Very few families take the number one precaution of locking exterior doors at all times,
whether someone is at home or not. Children who are in and out of the house all day leave
doors unlocked, as do people who step next door for a neighborly visit.
An example will illustrate just how hazardous an unlocked door can be.
A woman was in her house, not particularly concerned that her back door was unlocked, since
she had a large dog in whose presence she felt absolutely secure. Sure enough, an intruder
entered through the unlocked, and sure enough, the dog sprang to the attack, badly mauling the
intruder. Unfortunately, the intruder was a two-year-old who lived next door.
While doors should always be locked, this in itself is actually small
defense against the determined criminal. Here’s why:
• Doors often have small glass or light plywood panels, which can easily be broken or cut with
a rasp or a keyhole saw. Someone could then open the lock very easily by simply reaching
through the hole.
• A door that doesn't fit its frame properly can easily be forced open by wedging a tire tool
or prying bar between it and the frame and then " spreading" the door away until the bolt moves
free from the strike (the hole in the door frame that the bolt slides into when the door is
• Some older homes and apartments have doors that open outward. These can often be opened
simply by removing the hinge pins and lifting the entire door from the frame. The Multi-Lock,
mentioned later in this chapter, is useful in protecting doors of this type.
• Certain locks can be easily picked, removed, or destroyed.
It is virtually impossible to prevent someone from entering your home
through an outside door if that person is really determined to do so and has enough time and
skill to accomplish the deed.
If you can't entirely eliminate the possibility of someone's break into
your home, then what' the next best thing to do? Make breaking in as difficult and as
time-consuming as possible. And if the burglar still succeeds, at least you will have forced
him or her to destroy the lock or part of the door, or in some other way to leave clear evidence
of illegal entry. This will be very important when you file an insurance claim to recover your
loss. If nothing else, it will at least minimize the likelihood of your claim's being denied on
the grounds of negligence.
Strengthening doors — and these comments apply to all outside door - is not
difficult. First, the door itself should be as sturdy as possible. A hollow-core metal or solid
wooden door is best.
For aesthetic purposes, however, many prefer doors with heavy glass or wooden panels.
These types of doors offer considerably less protection than those just mentioned, but there is
one thing in particular that you can do to make them more secure: double-cylinder locks should
always be installed on such a door. This kind of lock requires a key to open it from the inside
as well as from the outside, which prevents an intruder from unlatching the lock by reaching
through broken glass or a hole in a wooden panel. That much delay — unless the burglar is
especially determined — will very often send an intruder of f to easier pickings. A word of
caution, however: in the event of fire or other emergency double-cylinder locks can delay
occupants from getting out of the house. Consequently, a key to the in side lock should always
be kept conveniently at hand.
There may be a reason why one of these measures won't be practical. For example, your
landlord might not want to replace an existing door or permit you to do so, or you, as a tenant,
might not want to go to the expense of installing a really good door on someone else’s
property. It may not be a thing of beauty, but it might save your TV, DVD, etc.
In securing all outside doors, be particularly meticulous with those that offer an
intruder cover — such as doors inside vestibules or enclosed porches. Here a criminal could work
at leisure, safe from observation by neighbors or passersby. Be aware that these protected
areas often are of less sturdy construction than other parts of your home. Ideally they should
be finished off with exterior walls as sound as the rest of the house.
Every exterior door should fit its frame snugly. Most don't. House-builders sometimes take shortcuts by making
the openings oversized, and even a well-fitted door can develop problems as a house settles on
its foundation. The best way to remedy a poor fit is to reinforce the door frame or to replace
the door with one that fits. If you don't want to go to that much expense, at least use locks
with bolts that slide a minimum of one inch into the frame, or attach a common thumb lock with
a long bolt to the inside face of the door. Or better yet, ask a locksmith about an L-shaped
metal strip that can be attached to a door frame to protect an inward-swinging door from being
jimmied with a crowbar. A flat plate attached to an outward-swinging door can be used to cover
such an opening, but it should be attached with flat bolts or non-retractable screws so that it
cannot be removed from the outside.
Storm doors are excellent energy savers, and when equipped with adequate
locking devices, they add an element of security by introducing an additional delay factor.
The glass and/or wrought-iron features serve as another deterrent.
In general, chain locks are not effective in preventing someone from entering your home. A good kick might easily pull
the lock away from the wall. Furthermore, the chain itself can be cut with a hacksaw or a bolt
cutter. To maximize the effectiveness of such locks, anchor them with long screws or, better yet,
bolts. A wedge-shaped rubber doorstop inserted beneath a door can add substantial additional
protection against unwanted entry.
One advantage of a chain lock is that, when it is engaged, it indicates to a burglar that someone is at home,
generally causing the burglar to move on. One distinct disadvantage of a chain lock is that a
burglar, once inside your house, can become relatively free from being surprised on the job
simply by engaging the lock him- or herself.
The value of a chain lock is thus debatable, but on balance a good one
is worthwhile, if for no other reason than its effect of delaying entry into your house. Also,
if you have solid doors without peepholes, a chain lock allows you to speak to visitors without
fully opening the door.
A solid exterior door should be equipped with a peephole (or interviewer or optical viewing device) simply to allow
you to ascertain who is outside before you open your door. Ideally, the peephole should have a
wide-angle lens. If at all practical, a convex mirror should be installed opposite the door.
With this device, you should be able to see anyone attempting to hide beyond the vision range
of the peephole.
Night Latches and Doorknob Locks
The night latch or rim spring latch commonly found in most older houses, and the cylindrical lock or lock-in-knob found in many
apartments and newer houses, do not offer a great deal of security. The lock-in device is
easily defeated by prying the entire assemblage loose with a crowbar. Night latches are very
common because they are inexpensive and convenient and because they can be engaged simply by
slamming the door shut. But often they can be opened by sliding a credit card or similar piece
of plastic into the gap between the door and the frame.
Newer night latches have protection to prevent the “credit card” entry into a structure.
This represents little, if any protection, however, as doors of this type can often be
compromised by forcing them open with a screwdriver. This can be prevented by equipping the
lock with an effective dead-latch plunger, which prevents pushing back the latch’s beveled edge.
Unfortunately, the faceplate can be pried loose and the cylinder removed quite easily. Thus,
this type of lock isn’t considered a satisfactory locking device.
Dead Bolt Locks
The remedy for these problems is a dead-bolt lock. Such a lock usually features a square-faced
(rather than beveled) bolt, which is engaged from the inside by the second turn of a key, or
else is operated by turning a thumb knob. Unquestionably, the dead bolt is superior to the
common night latch inasmuch as it cannot be forced open with a knife blade, spatula, or similar
implement. The shape of the bolt and the pressure required to move it in any way other than
through the normal use of a key or knob make these burglar tools useless. If the bolt is long
enough (a one-inch throw is recommended), the door becomes most difficult to jimmy open. Either
a variation on this theme, the rim- or surface-mounted vertical dead-bolt lock, or the
ring-and-bar lock is an even more effective protection measure. For high-risk applications, the
Multi-Lock is a dead-bolt lock that, when engaged, bolts into all four edges of the door frame.
A dead bolt is, dollar for dollar, the best means of defense that you can enlist in securing your home.
You definitely should install one on each outside door either in place of or supplementary to
whatever locking devices you are now using. A number of excellent dead-bolt locks are on the market.
Other Locking Devices
There are a number of virtually pickproof locks available, but they are
expensive and, except in the most extraordinary of circumstances, unnecessary for the average
homeowner. Few burglars are skilled at picking locks, so unless there are items of unusual value
in your home, installing pickproof locks generally would constitute overprotection.
Push-button combination types of locks are also generally available and are secure from lock
pickers, but a drawback is that the combination can be "read" even from great distances. Such
locks are therefore much more effective for interior security than for exterior use.
No lock can prevent a door from being opened through the application of brute force, especially if there is a weak door frame. The wooden door frame itself can present a problem. In many cases when a forced entry is made through a door, the dead bolt itself has held but the door frame around the strike plate has splintered. This can be overcome by ensuring that there is proper bracing in the wall behind the door frame. If you push against the door frame on the strike-jamb side and it bends outward, it is not well supported.
The proper combination for preventing the wooden door frame from splintering without determined attack is by using a high security strike box or plate and screws long enough to anchor the strike device into two-by-fours bracing in the wall immediately behind the strike device. A police brace, a long steel bar that reaches from the floor to the door at an angle, serves as an effective anti-intrusion device in much the same way as does wedging a piece of furniture under a doorknob. The top edge of the bar fits into a lock mechanism installed on the door, and the bottom fits into a metal socket in the floor. Another version of the police brace is a horizontal steel bar that is mounted across the center of the door. This fits jamb braces attached to both sides of the door frame. It can be removed or put back in place in a few seconds. Of course, these devices can be used only when you are on the inside. They do, however, have the very real advantage of being completely pickproof.
Another type of device favored for a high level of home security is tubular keyway lock. You have almost certainly seen the round locks found on many vending machines. Perhaps you have even seen the service person open the vending machine, using a small cylindrical key. This locking device has the advantage of being extremely difficult to pick and, for all intents and purposes, impossible to force open with a screwdriver or wrench. Other locks have similar advantages, and the configurations of the various available locking devices are many.
Of all the doors giving access to your house, probable the most hazardous are the patio doors – typically of the sliding-glass type. In general, such doors have locks that are none too effective. Even if they hold up against an intruder, a piece of glass can easily be cut or broken from the doors and the locks disengaged.
One safeguard is to attach locks with vertical bolts that fit into holes in the floor and upper frame and hold the door in place when it is engaged. Another safeguard is to substitute the panes of plate or tempered glass with polycarbonate or other shatterproof glass, or other types of impact-resistant glazing material. An inexpensive auxiliary means of securing such doors is to cut a broom handle to fit the track in which the doors slide. Thus, even if the lock were forced, the door would not slide open.
These highly susceptible openings into your home may be further protected by inserting screws into the upper track of the door assemblies. Properly placed, these screws can prevent the lifting and removal of an entire door, glass, frame, and all.
Garages and Outbuildings
Garage doors that lead directly into the house are, in fact, entry doors, in the same way as the front door. However, they represent a more serious threat to your security, because an intruder, hidden from sight in the garage, could leisurely breach your security and attack your assets or your family. At the very least, such an opening should be protected by a solid-core door, a dead-bolt lock, secure hinges and, if warranted, an intrusion alarm.
Obviously, you should keep your garage locked shut whenever practical. A ten-minute trip to the grocery could result in an intruder’s use of your unprotected ladder to gain access to a substantially more unprotected upstairs nursery.
All garages should be protected with good padlocks. A good padlock has a hardened (or, better yet, a stainless) steel shackle (the loop). This should be no less than 9/32 inch in diameter. It should have a double locking mechanism (heel and toe), a five-pin tumbler, and a key-retaining feature. This last feature, sometimes difficult to find, prevents you from removing the key unless the lock is engaged. Cane bolts and sliding hasps, installed on the inside, are inexpensive but highly effective means to increase the security of your garage.
Roll-up garage doors require two good padlocks for acceptable security, one on either side of the door. Sometimes upward pressure on one side of the door will cause the other side to rise enough for someone to crawl under. Many garage door assemblies, electric or mechanical, have predrilled holes on the tracks for a padlock, which, of course substantially increase your safety and perhaps your peace of mind.