Mortise Lock vs Rim Lock vs Deadbolt Lock — What’s The Difference?

When shopping for a digital lock in Singapore, one of the biggest mistakes homeowners make is buying a lock before understanding their existing lock system.

Most homes generally use one of these 3 lock types:

• Mortise locks
• Rim locks
• Deadbolt locks

Understanding the difference matters because it affects:

• Digital lock compatibility
• Installation complexity
• Security level
• Door hacking requirements
• Aesthetics
• Long-term usability

At Interlock Singapore, this is usually the very first thing we check before recommending any digital lock.

In this guide, we’ll explain:

• What each lock type is
• How they work
• Where they are commonly installed
• Their pros and cons
• Which is most common in Singapore
• Which digital locks are compatible
• What homeowners should know before upgrading

Quick Summary

Lock Type	Common In Singapore?	Security Level	Installation Complexity	Common Placement
Mortise Lock	Very Common	High	High	Main wooden doors
Rim Lock	Common	Medium	Medium	Metal gates
Deadbolt Lock	Less Common	High	Medium	US-style wooden doors

Understanding The 3 Main Lock Types

Before choosing a digital lock, it’s important to understand that not all locks are built the same way internally.

Some locks are:

• embedded INSIDE the door
• mounted ON the door surface
• designed purely for deadbolt security

This affects:

• how secure the lock is
• how the door must be prepared
• how the lock looks
• whether installation is simple or complex

A homeowner may look at 2 digital locks and think they are similar externally, but internally they may use completely different locking systems.

What Is A Mortise Lock?

A mortise lock is a lock system where the entire locking mechanism is installed INSIDE the door itself.

A pocket is cut into the door so the lock body can sit internally within the wooden structure.

This is the most common lock system used for premium digital door locks in Singapore.

Where Mortise Locks Are Usually Installed

Mortise locks are commonly found on:

• HDB main wooden doors
• Condo entrance doors
• Landed property doors
• Office wooden doors
• Fire-rated entrance doors

In Singapore, if you see a premium digital lock with:

• integrated handle with auto-locking feature
  
• Stainless steel with latch bolt, mechanical double lock
  
• emergency over-ride key can unlock or lock from outside

there is a very high chance it is using a mortise system internally.

Example Of A Mortise Digital Lock

Interlock Mercury X6 Mortise Smart Door Lock

The Interlock Mercury X6 is an example of a mortise-based digital lock system.

It uses an internal mortise body installed within the wooden door and combines:

• latch system
• deadbolt security
• handle mechanism
• smart lock functions

into one integrated system.

This type of setup is commonly used for premium smart lock installations in Singapore homes.

How A Mortise Lock Works

Source: Aspire Door: Mortise Fitting into a Door

A mortise lock usually contains:

• A latch bolt
• A deadbolt
• Internal handle mechanisms
• The mortise case/body

When the door closes:

• the latch keeps the door shut
• the deadbolt provides the main security locking

The entire mechanism works together inside the door structure.

Why Mortise Locks Are Popular

1. Better Security

Because the lock body is embedded inside the door, mortise systems are generally stronger and more resistant to forced entry.

2. Cleaner & More Premium Look

Most modern digital locks are designed around mortise systems because they look more integrated and seamless.

3. Better Smart Lock Features

Mortise systems can support:

• Auto-locking
• Handle lifting security
• Integrated handles
• Smart automation
• Multi-point locking systems
• Door viewer systems

This is why many premium smart locks use mortise designs.

Downsides Of Mortise Locks

1. More Complex Installation

Mortise systems require proper door cutting and alignment, usually with more holes being drilled into the door.

2. Different Mortise Sizes Matter

Not all mortise bodies are the same.

Common sizes include:

• 60mm
• 70mm

This affects compatibility during replacement.

3. Usually More Expensive

Mortise locks are often considered the premium category.

Important Singapore Considerations For Mortise Locks

In Singapore, some homeowners assume all digital locks are universal.

They are not.

Factors that affect mortise lock compatibility include:

• door thickness
• existing mortise size
• gate clearance
• door & gate handle positioning
• old lock hole positions (depending on backset used)

This is why compatibility checks are important before installation.

What Is A Rim Lock?

A rim lock consists of a front part and rear part with bracket, mounted on the surface of the door instead of being embedded inside it, via the centrally structured bind, sandwitching the wooden door.

The lock body is usually visible from the interior side of the door. The rear part of  lock provides the locking engangement onto the bracket from inside.

This makes rim locks easier to install and popular for retrofit situations.

Where Rim Locks Are Usually Installed

Interlock Mercury G3 Rim Lock Installed on Gate

Rim locks are commonly found on:

• HDB metal gates
• Older wooden doors
• Bedroom doors
• Add-on security doors
• Rental units
• Surface-mounted installations

In Singapore, many digital gate locks are technically rim lock systems.

This is because metal gates usually:

• have limited internal space
• cannot support deep mortise lock bodies easily

Example Of A Rim Digital Lock

Interlock Mercury G3

Interlock Mercury G3 Rim Lock

The Interlock Mercury G3 is an example of a rim-based digital gate lock system.

Instead of embedding a large lock body inside the gate structure, the locking mechanism is mounted onto the gate surface itself.

This makes rim systems ideal for:

• HDB metal gates
• condo gates
• retrofit gate installations

where internal space is limited.

How A Rim Lock Works

A rim lock generally consists of:

• A front surface-mounted lock body
• A horizonally or vertically mounted lock rear part with locking bolt
  
• A side bracket /strike plate on the door frame

Although the locking mechanism seems to be hidden inside the door, in fact, it is built in the rear part of the lock.

Why Rim Locks Are Popular

1. Easier Installation

Rim locks usually require less drilling and cutting or modification

2. More Flexibility

Certain doors may not have enough thickness or structure for modern mortise systems.

Can be installed onto thinner doors(35mm thickness door)  such as room door, office door, store room door, customised carpentery furniture door, etc.

3. Great For Metal Gates

This is one of the biggest reasons rim locks remain extremely common in Singapore.

Most metal gates are not designed for deep internal lock bodies.

4. Lower Cost

Rim systems are often more affordable compared to mortise locks.

Downsides Of Rim Locks

1. Needs Larger Surface Mounting Space

Usually, the inner body of a rim lock is mounted horizontally, which requires a wider mounting space on the door surface.

In some cases, protruding door architraves or decorative trims may obstruct the installation area. When this happens, partial removal or modification of the architrave may be required to allow the rim lock to fit properly and operate smoothly.

2. Generally Lower Security

Compared to deep mortise systems, rim locks are usually considered less secure structurally.

3. Less Premium Feel

Depends on the model, but many homeowners prefer the integrated look of mortise systems.

4. Lack of Emergency Management

No emergency key for most rim locks on wooden door.

Important Singapore Considerations For Rim Locks

When installing digital rim locks on gates, installers often need to consider:

• gate bar spacing/opening gap (can people from outside access through using their hands?)
• gate-to-door clearance (to accommodate the lock depth profile)
  
• gate handle & door handle distance (to accomodate space for door & gate lock)
• alignment with wooden door
• adequate space for mounting the bracket
  
• strike plate positioning
• suitable location on the gate for lock installation

This is especially important for dual-sync gate and door setups.

What Is A Deadbolt Lock?

A deadbolt lock is a dedicated security bolt that slides directly into the door frame.

Unlike spring latches, deadbolts do not retract easily under force.

Their main purpose is security.

Where Deadbolt Locks Are Usually Installed

Aqara U100 Deadbolt Lock Installed on Metal Gate

Deadbolt locks are commonly found on:

• American homes
• US-style wooden doors
• Airbnb units
• Simpler smart lock setups
• Secondary entrance doors
• Metal Gates

They are much more common in the United States compared to Singapore.

Example Of A Smart Deadbolt Lock

Aqara U400 Smart Deadbolt Lock

The Aqara U400 is an example of a smart deadbolt lock system.

Unlike a full mortise lock, the focus here is mainly on:

• the deadbolt mechanism
• smart access control
• simplified locking structure

Deadbolt systems are usually simpler compared to integrated mortise systems.

Why Is It Called A “Deadbolt”?

The term “dead” means the bolt does not use a spring mechanism.

This makes it harder to:

• force open
• shim
• push back

which improves security.

Types Of Deadbolts

Single Cylinder Deadbolt

• Key outside
• Thumbturn inside

Most common type.

Double Cylinder Deadbolt

• Key required on both sides

Usually used for higher-security setups.

Smart Deadbolt

Modern digital versions use:

• PIN codes
• fingerprint access
• app control
• motorised locking

Advantages Of Deadbolt Locks

1. Strong Security

Deadbolts are known for strong resistance against forced entry.

2. Simple Mechanism

Fewer moving parts compared to complex mortise systems.

3. Reliable

Very popular in countries like the United States.

Downsides Of Deadbolt Locks

1. Less Common In Singapore

Singapore homes usually use mortise systems instead.

2. Separate Handle Required

Deadbolts are usually separate from the door handle.

3. Fewer Integrated Features

Compared to premium mortise smart locks.

Why Many US Smart Locks Don’t Directly Fit Singapore Homes

This is something many homeowners don’t realize.

A lot of smart lock videos online are based on American deadbolt systems. The digital deadbolt is very popular for people to DIY to replace the mechanical deadbolt lockset without the additional drilling and cutting.

However, Singapore homes commonly use:

• Mortise systems
• Metal gate + wooden door combinations
• Different door thicknesses
• Different lock spacing standards

This is why compatibility checks are important before purchasing a digital lock.

Mortise vs Rim vs Deadbolt — Full Comparison

Feature	Mortise Lock	Rim Lock	Deadbolt Lock
Installed Inside Door	Yes	No	Partial
Main Security Level	High	Medium	High
Common In Singapore	Very Common	Common	Less Common
Installation Complexity	High	Medium	Medium
Appearance	Premium	Bulkier (rear part)	Minimal
Common Placement	Main wooden doors	Metal gates	US-style wooden doors

Which Lock Type Is Best?

There is no single “best” lock type.

It depends on:

• your door structure
• your existing lock system
• your security needs
• your renovation constraints
• whether you have a metal gate
• your preferred aesthetics

In Singapore:

• Mortise systems are usually preferred for main doors
• Rim systems are common for gates
• Deadbolt systems are less common locally

Why Your Existing Lock Matters Before Buying A Digital Lock

Before upgrading to a digital lock, your current lock setup determines:

• whether the new lock can fit
• whether drilling of new holes is needed
• whether the existing lockset (backset, drilled holes) can be reused, modfied, covered, or require touch-up
• what installation method is required
• what digital lock models are compatible

This is why professional assessment is important before purchasing.

Final Thoughts

Understanding the difference between mortise, rim, and deadbolt locks helps homeowners make better decisions when choosing a digital lock.

Each system has its own:

• strengths
• limitations
• compatibility requirements

At Interlock Singapore, we always recommend identifying your existing lock system first before selecting a digital lock model. Contact us here.

If you’re unsure what type of lock your home currently uses, you can always send photos of:

• door (full front, full rear, side)
• door frame (locking area)
• door & gate (full front view, in closed position)
• existing lockset
• some critical measurements

for compatibility checking before purchase.