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Door and Window Security

This page contains advice on how you can make your home safer, especially in relation to doors, windows and locking systems.

Door security

If your front and back doors are not secure, neither is your home. Two thirds of burglars gain entry through a door.

Remember, quality locks and bolts are only as strong as the door and the frame to which they are fitted. Wooden doors should be solid and at least 44mm (1 3/4 inches) thick. Check that the frame is well fixed, and if weak or rotten replace it.

Glass panels on or around doors are especially vulnerable, so it's worth replacing them with laminated glass.

If you replace a door it is better to buy a new 'door set' certified to British Standard PAS 24-1 'Doors of Enhanced Security'. Bought as a complete kit, this shows that the door, frame, locks and fittings have been attack tested.

  • BS:PAS24 door sets are available in different materials, so specify this standard if you are having replacement doors. 
  • Remember to fit all security devices with strong screws or bolts. 
  • If fitting locks to a standard door fit a 5-lever mortise lock tested to BS: 3621 plus a BS: 3621 night latch. See lock section below. 
  • Before fitting locks to PVC-U or metal doors, check with the installer to make sure that this will not affect your warranty.

Patio doors

Patio doors are especially vulnerable to break-in by levering off the tracks. When buying, ask for the sliding section to be on the inside and for anti-lift blocks. Multi-locking systems are recommended or have mortise security bolts with removable keys at the top and bottom of both doors. Existing patio doors can be fitted with additional security bolts to stop lifting or forced entry.

Door viewer

If you don't have a window in the door or some other way of checking who is calling, fit a door viewer. Look through this to identify callers before you open the door.

Door chains

These allow the door to be opened a short distance to allow checking of identification. They can stop callers pushing their way in, but must be securely fixed to avoid screws being pulled out. They do not contribute to the security of a locked door against burglary.


Check that the door hinges are sturdy and secured with strong, long screws. For added security, fit hinge bolts or security hinges. These are inexpensive, help to reinforce the hinge side of a door against force and protect the hinge if your door opens outwards.


Never hang a spare key inside the letterbox. This is an obvious place that a thief will check. Letterboxes should be at least 400mm (16 inches) from any locks. Consider fitting a letterbox cage or other restrictor, which prevents thieves from putting their hands or gadgets through the letterbox and trying the latches from the inside.


Mortise deadlock

Mortise locks fit into a slot cut into the edge of the door and usually can only be opened with a key. These should be upgraded to 5-lever locks tested to BS: 3621. This is usually a minimum insurance requirement. The locks are based on a range of standard measurements so, with careful matching, replacement is easy. The deadlock means a thief can't smash a nearby glass panel to open the door from the inside or, having entered through a window, cannot carry your belongings out through the door.

Rim lock or night latch

A rim lock is screwed to the face of the door and latches automatically when you close the door unless held open with the snib. Unless it also has the term deadlock attached, it can be opened by turning a knob. Rim locks should be tested to BS:3621

Automatic deadlocking rim lock

This locks automatically when the door is closed and is more secure than other types of rim lock. It needs a key to open it from both the inside and the outside and should meet BS: 3621.

Ideally both types of lock should be fitted to a door at roughly one third spacing. Both being used to secure the empty home and just the night latch for regular use during occupancy.

Multi-point locking

Multi-point locking involves several hooks or bolts holding the door into the frame. The lock cylinders should be tested to BS EN 1303 Grade 3 and can be replaced.

If your door is BS: PAS24 and it requires replacement locks ensure they are changed like for like to continue the level of security.

Window Security

Windows are a popular point of entry for burglars through breaking glass or just being left open. 

If you are replacing windows, take the opportunity to install windows certified to British Standard BS7950 'Windows of Enhanced Security' and consider using laminated glass in ground-floor and accessible windows such as those above a flat roof.

Ground floor opening windows and easy to reach windows, such as above a flat roof or near a drainpipe, should have locks unless used as a fire escape in which case laminated glass still provides security. Even small windows such as skylights or bathroom fanlights need locks. If a thief can get their head through, with a bit of effort the body can follow.

Grilles, Shutters & Window Protection

Consider fitting security grilles or shutters to vulnerable windows - but only if these windows are not escape routes in case of fire. Glazing may be further protected with the addition of accredited adhesive window film.

Fire Safety

When you are fitting security devices, you must consider the risk of fire and not fit systems that will prevent escape from occupied buildings. For example, fitting and padlocking a steel bar gate over the face of a standard front door in a house will impede escape and misplacing the extra keys may prove fatal. On the other hand, a BS: PAS24 door and frame provides better security and does not increase the fire risk. A window that may be used as a fire escape to a flat roof should not have a lock and key, but if fitted with laminated glass still provides security.

Expert advice

For more information on types of locks and locksmiths visit the Master Locksmiths Association website.


Do you need a quick answer to a general question? Then we recommend you visit the national Ask The Police web site.