Types of Door Locks: How to Choose the Right Lock for Every Door in Your Home

Most homes have more than one type of lock, and each door does a different job. The front door has to be secure but easy to use every day. A sliding door needs protecting against being forced or lifted. An internal garage door is an entry point many people forget about. At Lock, Stock & Barrel Locksmiths, one of the first questions homeowners ask us is which parts we’ll be using and why. This guide explains the main types of door locks used in Australian homes, where each one works best, and what to think about before you upgrade.

The Main Types of Door Locks Explained

Deadlatches

A deadlatch is the lock you’ll find on most Australian front doors. It has a spring-loaded latch that locks automatically when the door closes, so you can’t accidentally leave the door on the latch. It can also be deadlocked: turning the key from outside, or pressing a button or snib inside, stops the latch from being pushed back with a card or thin tool. That combination of everyday convenience and extra security is why deadlatches are so common on main entry doors.

Deadbolts

A deadbolt is a separate, solid bolt that you throw into the door frame with a key or a thumb-turn. It has no spring, so it can’t be slipped back and it stays put until someone deliberately unlocks it. Deadbolts are often fitted above an existing handle or deadlatch to add a second point of locking on front and back doors. For a closer look at how they work and the different styles available, see our guide on everything you need to know about deadbolts.

Single-Cylinder vs Double-Cylinder Deadlocks

A single-cylinder deadlock uses a key outside and a thumb-turn inside. A double-cylinder deadlock needs a key on both sides. Double-cylinder locks are popular on doors with glass panels or sidelights, because someone who breaks the glass still can’t reach in and unlock the door. The trade-off is safety: in a fire, you need that key to get out. Fire and Rescue NSW lists deadlocks among the security features that can slow an escape and advises making sure keys to all locked doors are readily accessible. If you choose double-cylinder locks, keep a key somewhere everyone in the household knows about. Don’t leave it in the lock where it can be seen through the glass.

Mortice Locks

A mortice lock is fitted into a pocket cut into the edge of the door rather than mounted on its surface. Because the lock body sits inside the door, it’s generally more robust and harder to attack. Mortice locks are common on commercial premises, older homes and heavier timber doors, and they’re often paired with lever handles. Fitting one properly takes accurate cutting, which is why it’s usually a job for a locksmith. Our page on mortice lock installation goes into more detail.

Lever and Knob Locksets

Lever and knob locksets combine the handle and lock in one unit. They’re ideal for internal doors such as bedrooms, bathrooms and home offices, where you need privacy rather than high security. Lever handles are also easier to use for children, older family members and anyone with limited grip strength. On their own, they’re not designed to be the main lock on an external door. If you’re weighing up styles, our guide to lever handle locks explains the options.

Patio Bolts and Sliding Door Locks

Sliding doors are often the weak point of a home. Their built-in latches tend to be light-duty, and a poorly secured sliding door can sometimes be forced or lifted off its track. A patio bolt is a key-operated bolt fitted to the frame of a sliding door. It locks the door firmly in place, adding a second point of security independent of the main latch. For sliding doors, it’s one of the most effective and affordable upgrades you can make.

Which Lock for Which Door?

Every home is different, but this is how we typically approach each door:

• Front door: a quality deadlatch, often with a deadbolt added for a second locking point. Consider a double-cylinder lock if the door has glass nearby.
• Back and laundry doors: these are usually less visible from the street, so they deserve the same protection as the front door, not less.
• Sliding and patio doors: a patio bolt alongside the existing latch.
• Internal garage access door: treat this as an external door. If someone gets into the garage, this door is all that stands between them and your home.
• Internal doors: privacy or passage sets with lever handles or knobs.
• Side gates and sheds: a lockable gate latch or good-quality padlock, so tools and ladders can’t be used to access the house.

Windows matter too. Locks on doors won’t help much if an easy-to-open window sits nearby. We cover this in our guide to window lock installations and restricted key systems.

What to Consider Before You Upgrade

The condition of the door and frame

A lock is only as strong as what it’s fitted to. A solid lock on a hollow-core door or a soft, damaged frame won’t perform the way it should. Part of choosing the right lock is checking that the door, frame and strike plate can support it.

How many keys you want to carry

If you’re replacing several locks, it’s worth having them set up to work on one key. A keyed-alike system means the front door, back door and patio bolts can all open with the same key. That’s far more convenient than a bunch of keys you can never tell apart.

Who can copy your keys

Standard keys can be copied at most key-cutting counters. With a restricted key system, copies can only be made with the owner’s authorisation, which gives you much tighter control over who has access to your home.

Renting or living in a strata building

If you rent, check with your landlord or agent before changing or adding locks. In NSW, tenants generally need the landlord’s agreement, and both parties must be given a copy of any new key. If you own an apartment, your front door may form part of the common property, so the owners corporation may need to be involved. Our article on changing the lock on your apartment door explains what to check first.

Professional Lock Installation Across the North Shore

Choosing the right lock is half the job. Fitting it correctly is the other half. A lock that’s poorly aligned, fitted to a weak strike plate or installed in the wrong door won’t give you the security you’re paying for. As licensed Master Locksmiths and members of the Master Locksmiths Association of Australasia, we supply and fit residential locks and explain exactly which parts we recommend and why before any work starts.

Our team is based in Turramurra and works throughout the Upper North Shore and surrounding areas, from homes in St Ives to Thornleigh. To upgrade the locks in your home, visit our lock installations and repairs page or call us on 0411 700 072.

Frequently Asked Questions

What is the difference between a deadlatch and a deadbolt?

A deadlatch has a spring-loaded latch that locks automatically when the door closes and can then be deadlocked for extra security. A deadbolt is a separate solid bolt with no spring, which only moves when you lock or unlock it with a key or thumb-turn. Many front doors use both.

What is the best type of lock for a sliding door?

For most homes, a key-operated patio bolt fitted alongside the existing sliding door latch is the most effective upgrade. It secures the door independently of the latch and makes it much harder to force the door open.

Are double-cylinder deadlocks safe?

They’re a strong choice for doors with glass nearby, but they need a key to open from the inside. Fire and Rescue NSW advises keeping keys to all locked doors readily accessible so everyone in the home can get out quickly in a fire.

Can I have all my new locks work on one key?

Yes. Most residential locks can be supplied or set up to be keyed alike, so one key opens every external door.