A deadbolt lock serves as a back up for lockset on entry doors to provide maximum security. The locks found in most doorknobs are called spring-bolt locks because it is held in place only by the pressure of a spring and therefore can easily be retracted. A deadbolt lock cannot be opened except by rotating a lock cylinder.



A deadbolt is often activated from the inside by turning a separate knob and from the outside by using a key. A solid steel latch at least one inch long exits the edge of the door and passes into the doorjamb when a deadbolt is operated.

The bolt locks the door into the frame, therefore the longer the bolt the harder it would be for the door to be pried open. The weight of the locking bar in deadbolt locks alone is usually sufficient to increase break-in time to 10 or 15 minutes. Better units have a stainless steel bolt with a roller insert to resist sawing and cutting.

A vertical deadbolt, which generally rests on top of a door, is a variant of standard deadbolt. Vertical deadbolts resist jimmying, a process in which an intruder inserts a pry bar between the door and the frame and tries to pry the bolt out of the jamb.

There are generally two kinds of deadbolt locks, the single and the double cylinder deadbolts. A single-cylinder deadbolt is key-operated from the outside and has a simple twist knob or button on the inside. This kind of deadbolt lock is recommended for solid metal or wood doors.

A double cylinder deadbolt, on the other hand, uses a key on both sides of the door. This is recommended for glass doors as it would thwart attempts by burglars to open the door by breaking the glass and reaching inside.

Remember though that double cylinder deadbolts can trap people inside in case of an emergency like a fire as keys can be easily misplaced. If you have double cylinder deadbolt locks at home be sure to keep a spare key nearby. It is actually advisable to leave the key inside the deadbolt when you are inside the house.

There are modern deadbolts available like the electronic keyless variety entry with motion detectors. This kind of deadbolt would come in handy if you come home with a handful of groceries. The computer chip inside such deadbolts can also be programmed to lock the door after a certain time has lapsed in case someone has forgotten to lock the door.

Keyless entry deadbolt is also equipped with the latest rolling code technology which randomly selects a new entry code from 4 billion possibilities making it impossible to open even by the shrewdest of burglars.

For peace of mind, it is highly suggested that you hire a professional to install your new locks as he or she can evaluate your existing doors and door frames.

What's the use of installing a deadbolt if your door can actually be kicked in? A skilled or experienced lock installer is required if you want your deadbolt to protect you the way that it should.