Mortice lock

A mortice lock is one that sits inside the edge of the door, in a pocket cut into the timber or the frame profile, so that only the forend, the cylinder and the handles can be seen. It is the most common type on the front doors of flats and villas and on almost every internal door.

Because it sits inside the door leaf it is out of the way and protected, but its size is limited by the thickness of the door. To replace it you have to match the size of the case and the distance from the forend to the centre of the cylinder, known as the backset. If they do not match, the timber has to be cut back or gaps filled.

Before you buy a replacement, send us a photo of the door edge with the lock in view and we will tell you which model fits. We cover this under lock installation.