Under Lock and Key – What you should consider when selecting locks

July 24, 2019 10:25 am Published by

Increasingly domestic and commercial buildings insurance are specifying the type of lock that should be used in different door and window types. There are many different options available and selecting the right one for your application can be difficult

The first question is: Are you replacing an existing lock? If so that narrows the options considerably, although even then improving the security of your door can be achieved. Next we need to think about the position of the door, internal or external? From there you can start selecting the best lock for you.

Cylinder Locks

Where most cylinder locks are symmetrical and can be accessed from both sides there are other options.  A single, or half, cylinder, is half the length of a regular cylinder, and only one side works with a key, the other being blank. This is ideal when you only want to lock the door from one side. A Thumbturn cylinder works well on back doors or patio doors. On the outside the cylinder is locked by a key while on the inside you just need to twist the knob, or thumbturn, to unlock the door. This is also useful on doors that may be used in an emergency when a quick exit is required. An offset cylinder has halves that are not symmetrical. This type of cylinder is most commonly used on UPVC or Composite doors.

Mortice Locks

Many insurance companies require fitting a five-lever mortise deadlocks as a minimum standard for external doors. Mortice locks are embedded in the door and require a key to be turned to activate the deadlock. The advantage of this is that burglars cannot smash an adjacent window, reach inside and unlock the door, as may be possible with a cylinder rim (Yale) lock. The deadlocks on a mortice lock also mean that if a burglar breaks in through a window they cannot leave through the door, as long as they have no access to a key. 


A Night Latch, which you may know as a yale lock, or rim lock is commonly found on domestic front doors. They are mounted to the inner surface of a door.  When the door is closed the night latch automatically latches the door shut. They are available as either non-deadlocking where you simply shut the door and it is locked, or with a deadlock where you can deadlock the latch from the outside with a turn of the key. Some Nightlatches will also allow you to lock the turn knob on the inside with the same key. This will prevent slipping from outside and the knob being turned by sticks, cables and so on through the letterbox


At express Property Services we have been supplying, fitting and repairing locks for nearly thirty years. We offer a free on-site security consultation, as well as emergency call out services. Please get in touch to learn more about our lock services. 

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This post was written by Express Property Services