Blog Article
Types of Door Locks Explained: A Plain-English Guide for Homes and Businesses
Deadlocks, deadlatches, mortice locks, lever sets, knob sets, sliding door locks, digital locks and more — what each does, where it suits, and what to ask before buying.
Types of Door Locks Explained: A Plain-English Guide for Homes and Businesses
Walk into a hardware store and you'll face a wall of locks with names like deadlatch, mortice and single cylinder. Choosing the wrong one is easy. It might not fit the door, might not suit how you live, or might give less protection than you expected.
This guide explains the main lock types in plain English, so you can choose with confidence or have a better conversation with your locksmith.
First, a few terms
- Cylinder: The part your key goes into.
- Bolt: The metal piece that extends into the door frame.
- Strike plate: The metal plate on the frame that receives the bolt.
- Backset: The distance from the door edge to the centre of the keyhole or handle. It matters when replacing a lock.
- Deadlocking: The bolt can't be pushed back by force or a card once locked.
The main types of door lock
1. Deadlatch (nightlatch)
What it is: A rim-mounted lock on the inside face of the door that latches automatically when the door closes. Many can then be deadlocked with a key.
Good for: Front doors, where you want the door to latch behind you.
Watch out for: Self-latching makes it easy to lock yourself out. Choose a model that deadlocks for better security.
2. Deadbolt
What it is: A solid bolt thrown by key or turn-knob. It doesn't spring back like a latch.
Good for: Adding a strong second lock to an external door.
Watch out for: It only protects you if you remember to lock it.
3. Mortice lock
What it is: A lock body set inside a pocket cut into the door edge, often with both a latch and a deadbolt.
Good for: Solid timber doors, period and character homes, and many commercial doors. It looks neat and is very robust.
Watch out for: It needs a door thick enough to take it. Replacement must match the size and backset.
4. Lever and knob sets
What they are: Handle sets with a latch, sometimes with a key or privacy button.
Good for: Internal doors, bathrooms and bedrooms.
Watch out for: Lever and knob sets on their own are generally not sufficient security for external doors. Pair them with a deadbolt or deadlatch.
5. Entrance sets with deadlocks
What it is: A matched handle and deadlock set, popular on modern front doors.
Good for: A coordinated look with good everyday security.
6. Sliding door locks
What they are: Hook-bolt locks and secondary locks designed for sliding doors.
Good for: Glass sliding doors, often a weak point in homes.
Tip: Add a secondary lock or anti-lift device.
7. Security screen door locks
What it is: A lock on a security screen or grille door, often triple-locking.
Good for: An extra layer of security and ventilation.
8. Digital and keyless locks
What they are: Locks opened with a code, card, fob, fingerprint or phone app.
Good for: Households with lots of comings and goings, rentals, and businesses that need to change access quickly.
Watch out for: Battery life, a backup way to get in, the quality of the product and app support. Choose reputable brands.
9. Padlocks and gate locks
Good for: Gates, sheds and storage.
Tip: A strong padlock is wasted on a weak hasp. Secure both.
Which lock for which door?
| Door | Common choice |
|---|---|
| Front door (timber) | Deadlatch + deadbolt, or a mortice lock |
| Front door (modern) | Entrance set with deadlock, or a quality digital lock |
| Back / side door | Deadbolt + lever set, or a mortice lock |
| Sliding door | Hook-bolt lock + secondary lock |
| Internal doors | Lever or knob set |
| Bathroom | Privacy set |
| Garage internal door | Deadbolt |
| Shopfront | Commercial mortice or specialised shopfront lock |
| Gates and sheds | Quality padlock and hasp, or a gate lock |
What to check before buying a new lock
- Door thickness and material. Not every lock fits every door.
- Backset. Measure it if you're replacing an existing lock.
- Handing. Some locks are made for left- or right-hand doors.
- The frame. A strong lock in a weak frame is still weak.
- Fire and exit rules. Especially for businesses and some apartments.
- Your lifestyle. Do you often leave keys inside? Do lots of people need access?
- Key matching. Can it be keyed to match your other locks?
The hidden factor: installation quality
Even an excellent lock performs poorly if it's badly installed. Short screws, misaligned strike plates and poorly cut mortices all reduce security and cause faults. Good installation includes:
- Long screws into solid framing
- Precise alignment of bolt and strike plate
- A smooth action with no forcing
- A final test of every function
Frequently asked questions
What's the difference between a deadlock and a deadlatch? A deadlatch latches automatically when the door closes, and can usually then be deadlocked. A deadbolt or deadlock has to be locked deliberately.
Are digital locks secure? Quality digital locks from reputable makers can be very secure. Always make sure there's a reliable backup way to get in.
Can I keep my old door and just upgrade the lock? Usually, yes, provided the door and frame are in good condition.
Need help choosing?
Locksmith Of Brighton supplies and fits locks for homes and businesses, and will recommend what genuinely suits your door. See our lock installation and lock replacement services, or contact us.