Sashlocks

Aged Brass 3" 5 Lever BS Sash Lock, from our current range.

What is a sashlock?

A sashlock is a type of mortice lock that combines a lock with a sprung latch, operated by a lever handle or knob. This means the door can simply be pushed shut and held closed by the latch during the day, without needing to be locked every time, while still offering a separately operated deadlocking function by key when full security is needed, such as overnight or when leaving the house.

Because they cover both everyday use and full security in one lock body, sashlocks are the most commonly specified lock type on UK external doors.

Where sashlocks are used

• Front and back doors – the standard specification for a timber external door, paired with a lever handle
• Doors used frequently through the day – the sprung latch means the door can be shut without locking it each time
• Insurance-rated installations – British Standard sashlocks are commonly specified to meet home insurance requirements

Choosing the right sashlock

A few practical points are worth checking before you buy:

• British Standard certification – look for BS3621 or equivalent if required by your insurance policy
• Case size – commonly 2½" or 3"; match your door and existing mortice if replacing a lock
• Lever count – 5 lever sashlocks are the standard for external doors; fewer levers may be adequate for internal use
• Handle compatibility – sashlocks are operated with a lever handle or knob; see our Lever Handles guide

Related products

Browse our current range in Locks & Latches, or see the related Mortice Locks and Deadlocks guides.

Frequently asked questions

What's the difference between a sashlock and a deadlock?

A sashlock includes a spring latch operated by a handle, so the door can close and hold shut without being locked. A deadlock has no latch and only locks or unlocks by key.

Can I fit a sashlock myself?

Fitting a sashlock involves cutting a precise mortice into the door edge and matching keeps into the frame, which is more involved than a straightforward handle swap. Many customers prefer a joiner to fit a new mortice lock, especially on an existing door.

Do sashlocks come in different sizes?

Yes, commonly in 2½" and 3" case sizes, along with different backset measurements. Matching the size to your door and any existing mortice avoids extra joinery work.

Back to the Locks & Security Guide, or explore the full Knowledge Centre.