Practical Home Security Measures That Work

Taking precautions

‘As safe as houses’ is a saying which no longer rings true and it is necessary to pay increasing attention to security — both the security of the home and our possessions, and personal security. A break-in is a traumatic experience, with loss of personal belongings, desecration of the home, which is always associated with a break-in, and possibly even personal physical injury by the intruder. Such facts must be faced and action taken to guard against them.

This post deals with all these aspects of security, and also includes precautions against fire which is another potential hazard to a house and its occupants.

Before going into details, there are some general observations on home security which are worth bearing in mind Obviously, there is tremendous value in locking all external doors and windows (and removing the keys from the locks) as this in itself often deters the casual, opportunist thief. With regard to locking internal doors, this must be a personal decision. Modern internal flush doors are so flimsy that it is probably best not to lock them, because once indoors the thief will not hesitate to smash them, causing even more damage. However, in an older house where the doors are a lot more substantial, it can be a good idea to lock those which lead into the hall from rooms which are vulnerable to entry, such as those with French windows or those leading to an attached garage, for example. In this case, security rack bolts at top and bottom of the door are called for.

When choosing locks, examine them carefully to satisfy yourself that they are strong enough for the required purpose; quality can vary considerably from one make to another. If you are uncertain as to what type to buy, remember that for excellent free advice on this subject, and indeed on all aspects of home security, you can consult the crime prevention officer at your local police station.

When you fit security devices to doors and windows bear in mind that they will be useless if a burglar can unscrew them. So where this seems likely to be possible, fix the device with cross-slot, Supadriv-type screws and, after fitting, drill out the screw heads to the depth of the recess so that it is impossible to remove the screws.

Remember, too, that windows are a very popular means of entry for an intruder, so anything you can do to improve the security of the glass will be worthwhile. Fitting safety glass, which is very difficult to break, is a good precaution, and so is fitting double glazing, especially factory-sealed units. Ordinary glass can be made more secure by fixing clear, self-adhesive safety film over the inside surface. Do, however, make certain that the opening windows can be unlocked easily, by key, from the inside in case of fire.

Danger points

Some parts of the house are far more liable to break-ins than others, so it pays to learn where these danger points are and to take extra-special care here. If nothing else, extra locks in these areas can delay a thief’s entry and this may even be enough to deter him in favour of other easier pickings.

Good visibility

Ground-floor doors and windows are obviously the most vulnerable, so try to make the thief’s task as hard as possible by ensuring that all doors and windows are visible to neighbouring properties. This means keeping trees and bushes around the house clipped well back. Also try to ensure that anyone approaching the house is in clear view by keeping the front-garden path and driveway clear of bushes and making sure that the area is well-lit at night.

External Door Security

The front door should be fitted with both a deadlocking rim latch which cannot be opened using flexible plastic pushed between the edge of the door and the frame, and a five-lever mortise deadlock which is much better than a rim latch in resisting drilling, forcing and picking. Also fit a door viewer and security chain to foil the barge-in thief.

Garage doors should be firmly secured with a strong lock and bolts, or a padlock and locking bar. A communicating door between an attached garage and a house should be fitted with a mortise deadlock, plus lockable bolts top and bottom on the house side. Back- and side-entrance doors need similar protection.

Glass doors should be fitted with toughened glass or sealed double-glazing units. French doors and patio doors are usually very vulnerable, so fitting additional locks and security devices to these is essential.


With windows, double-glazing units are a good deterrent. Some louvre windows are danger points because the glass slats are very easy to remove, while top-hung casements are a risk because, once open, they allow the thief to reach and operate the side window-handles. Therefore, fit window locks to all opening windows.

Upstairs windows above the roof of a porch or attached garage are particularly at risk, and so are those accessible from a drain-pipe, such as the bathroom window. Even skylight windows, particularly those with external hinges and fasteners, are vulnerable, especially if near a flat roof.

Finally, be sure to lock away ladders and DIY tools which may be easily taken from an unsecured shed or garage.

External doors

External doors should be secure enough not only to prevent break-ins, but also to act as a barrier to stop intruders who may have got into the house via a window from leaving with your bulkier belongings.

It is no good relying on locks and bolts alone as these will be useless if the door is weak and easily smashed. So make sure that doors are in good condition and are an exterior-quality type, at least 44mm thick and, ideally, are made from hardwood. Weak door-frames can be reinforced by screwing a length of angle-iron to the inside of the frame and to the adjacent wall. If the door has glass panels these should be either laminated or toughened safety-glass. Apart from being safer in an accident, safety glass is much more difficult for an intruder to break.

Because the front door is the one by which you leave and enter the house it tends to be the most vulnerable from the security aspect because it cannot be bolted when you are out. In addition to security deadlocks, fit good bolts at the top and bottom for use at night and if you are out of earshot in the back garden. Side and back doors also need bolts at the top and bottom to prevent them from being kicked in.

Surface-mounting bolts

The most common bolts are the traditional, surface-mounting sliding bolts. These are available in various sizes and patterns in steel and brass. The steel bolts are the stronger and a minimum bolt length of 200mm is required for external doors. Because the staple for bolts of this type tends to be made from thin steel and be held to the frame by only two screws, these bolts are fairly easy to force. Also, if a bolt is quite near to a window pane, it can often be a simple matter to reach it and slide it back. Apart from using long round-head screws to hold the staple, the strength can be considerably improved by mounting the bolt vertically so that it slides into a hole in the floor and in the head of the frame.

Mortise bolts

The best type of bolt is the mortise rack bolt, or security mortise bolt. These are fitted at the top and bottom of the door in holes drilled in its edge, which makes them difficult to tamper with. Also, since the bolt, which is wound out by a special key, shoots securely some distance into the door-frame, it is virtually impossible to break it out.

Mortise locks

The most secure lock for an external door is a mortise deadlock which is fitted into a slot cut in the edge of a door. In the case of a side or back door this may be the only type of lock on the door, but with a front door it is a good idea to fit this type of lock even if there is already a rim latch fitted. With mortise locks, turning the key shoots a bolt into a hole cut in the adjacent door-frame, and when the key is removed the bolt is deadlocked, which means that it cannot be retracted without using the key.

As long as the lock meets British Standard BS 3621 it will give a high degree of security. However, fitting this type of lock can weaken a door, and for glass-panel doors with narrow stiles there are special slim versions which reduce the problem. If the door will be severely weakened by fitting a mortise lock (that is when the stile is less than 44mm thick or 63mm wide) then fit a deadlocking rim latch instead.

Types of mortise lock

For a front door, most mortise locks will just have a key-operated deadbolt because the door will be held closed automatically by the rim latch, but for side and back doors it is usual to fit a two-bolt mortise lock. This type has a conventional key-operated dead-bolt, and in addition a springbolt which is operated by a handle or a door knob. This type of lock allows the door to be used from either side without a key, yet by using the key the door can be locked from inside or outside. Again, these locks must be to BS 3621 (or be five lever and of equivalent security) — two- or three-lever locks are inadequate.

Keys to pass

When ordering front- and back- or side-door mortise locks at the same time, you can ask for a key to be made ‘to pass’. This will operate both locks saves bulk on your key-ring and means less keys to be lost.

Rim locks

Rim locks are simply mounted on the inside face of a door. They are useful in addition to a good mortise lock on a front door, or they can be used as an alternative where the door is too thin or the stile of the door too narrow to allow a mortise lock to be fitted.

Types of rim lock

There are various types of rim lock. The simplest is the cylinder rim-nightlatch which is totally insecure as it can be opened easily in several ways, such as by breaking an adjacent pane of glass, by pushing back the latch with a sheet of plastic, or by exerting the minimum of force on the door.

For security, either an automatically deadlocking rim latch, or a deadlockable latch is required, both of which should be made to BS 3621. The automatically deadlocking rim latch has a springbolt with a mechanism to prevent the bolt being forced when the door is shut. This lock should be key-operated from both sides of the door to deadlock the internal handle, knob or lever. With a deadlockable latch the springbolt is not automatically deadlocking, but it can be deadlocked, together with the internal handle, by turning the key. Apart from being essential with glass-panelled doors, deadlocking latches are useful in any case because they prevent intruders from leaving the property easily.

Patio doors

There is little that can be done to improve locks fitted to sliding patio doors, so make sure that a secure type is fitted from the outset. The best type is a cylinder-operated hook-bolt lock. One problem with aluminium doors is that the metal, being soft, is very easily drilled and prised open. To overcome this, some manufacturers fit a locking mechanism with bolts which shoot out of the top and bottom of the door to prevent it from sliding and from being lifted out of its track.

With an existing patio door there is little to do except fit sliding-door locks to the top and bottom of the fixed frame. A steel bolt, which is locked by means of a key, can be pushed into a hole drilled in the sliding frame. A second hole can be drilled a short distance from the first to allow the door to be opened fractionally for ventilation.

Locking plate recessed in the fixed part of the door jamb. When the door is closed, the bolts engage in the locking plate preventing the door from being removed from its hinges.