Mortice and Sash Locks

These locks are available with deadbolts, latches or a combination of both (when they’re called sash locks) and hook and claw bolts that are used for sliding doors. They are fitted inside a mortice cut out of the door. They are available in two different sizes to suit the width of the door style into which they are fitted and are operated either by a cylinder lock or levered lock.

They come in two different sizes 67mm and 79mm. Mortice locks shouldn’t be fitted to doors that are less then 44mm thick, although if your door is a couple of millimeters out the wrong way it can be fitted with a reinforcing kit, which bolts through the door and sandwiches the door and lock together. When you turn the key the bolts are thrown into a boxed keep, cut into the door frame.

Your Insurance

Most home insurers require at least one of the locks on your external doors to have either 5 levers, so the first thing you need to do is to check. Remember, we are not talking about multi-point locks here, we are talking about timber doors, some composite doors, some steel doors and some old aluminium doors that use a mortice deadlock or sash-lock instead of a multi-point lock. If the mortice lock is certificated to BS 3621 you will clearly see the British Standard kite mark on the face plate of the lock. If this isn’t present then it could be a lock from Europe, which hasn’t been tested to the British Standards, but maybe to the European standard of EN 12209. Try to identify the manufacturer, which if not on the face-plate of the lock may be on the key and speak with your insurers to see if the lock is acceptable. If they need more information then you’ll probably have to take it out of the door and pop along to a locksmith for an expert opinion. If you do this, please leave somebody at home! If the lock is not up to the job and is unacceptable to your insurer you’d better change it for one that is. If you’ve had to speak with your insurers about whether a particular lock (or door) is acceptable for your cover make sure they confirm this to you in writing.

Mortice deadlocks will include the following security features:

  • For lever operated locks there will be a minimum of 2,000 key differs, which means a thief would have to carry 2,000 keys for your make of lock to be certain of unlocking your door and even then he could be there for 3 hours trying all the keys before he gets lucky!
  • For cylinder operated locks the cylinder must be certificated to BS EN 1303 as having Grade 5 key security, a minimum Grade 0 attack resistance and a Grade 2 drill attack resistance
  • Hardened steel spindles in the brass deadbolt or a hardened steel deadbolt to prevent the cutting of the deadbolt
  • A hardened steel plate over the lock casing to prevent drilling through the lock
  • A substantial boxed keep to receive the deadbolt.

These are almost identical to the mortice deadlocks described above, but incorporate a live bolt or latch in addition to the deadbolt. They are normally positioned just below the centre of the door to miss the joint between the mid rail and latching stile. These are used in private flat entrance doors (with an inside thumb turn operated deadlock if the flat is above ground floor) and in back and side doors of houses when they are normally supported with a pair of mortice security bolts. Exactly the same security standards and features as mortice deadlocks above apply.