What is a Semi-detached House and How Does it Differ From a Duplex?

If you’re searching for a home in Australia, you may come across the term "semi-detached house." It's often used interchangeably with duplex, but they’re not quite the same. Understanding the differences can help you make smarter property decisions, especially when it comes to long-term living or investment plans.

A semi-detached house is one of two separate homes that share a common wall but sit on their own titled land. A duplex, on the other hand, can share a wall or be stacked, and it might be on a shared title or strata-titled property. This article breaks down the differences so you can weigh the pros and cons for your lifestyle or investment goals.

What is a Semi-detached House?

A semi-detached house is a single-family home that shares one wall with another dwelling. Each home typically has its own entrance, driveway, garden or yard, and land title. In most cases, these houses are built as a pair and mirror each other in layout.

You’ll often find semi-detached homes in suburban areas where developers want to make better use of land without building apartment blocks. These homes provide a balance between the space of a detached house and the affordability of a townhouse.

In Australia, semi-detached homes are commonly Torrens titled. This means each side is legally a separate property with its own land and title, giving owners full control without needing strata agreements.

What is a Duplex?

A duplex is a residential building that contains two homes. These might be side by side, stacked on top of each other or connected in other ways. Duplexes can be Torrens titled, strata titled or company titled. The type of title affects how much control each owner has over the property.

For example, a Torrens title duplex allows each owner to have full ownership of their half and the land it sits on. Strata title duplexes share common areas like driveways, gardens or roofs. Owners in this case form a body corporate to manage shared spaces and insurance.

Duplexes are often built for investors or multi-generational families who want to live close but independently. In some councils, dual occupancy designs that qualify as duplexes offer ways to maximise rental income or build wealth on one block.

Key Differences Between Semi-detached Homes and Duplexes

Here’s a side-by-side comparison to clarify the differences:

• Common Wall: Semi-detached houses usually share one wall. Duplexes may share one or more walls or be stacked.
• Title Type: Semi-detached homes are typically Torrens titled. Duplexes can be Torrens, strata or company titled.
• Ownership: Semi-detached homes have separate titles. Duplex ownership may be separate or shared, depending on the title.
• Outdoor Space: Semi-detached homes typically have private yards. Duplexes can have private or shared outdoor areas.
• Body Corporate Requirement: Not needed for semi-detached homes. Required for strata titled duplexes.
• Use Case: Semi-detached homes appeal to owner-occupiers and investors. Duplexes suit investors or extended families.
• Subdivision Potential: More straightforward for semi-detached homes. Duplex subdivision depends on zoning and title type.

Pro Tip: Always confirm title type before purchase. It directly affects your level of control, ongoing fees and ability to renovate or sell.

Design and Layout Considerations

Semi-detached homes are often symmetrical and mirror each other in layout. Think of two homes with a shared wall in the middle, each with its own entrance and backyard. This layout allows for privacy while still fitting two dwellings on one lot.

Duplexes, especially newer ones, can vary more in design. Some are built vertically with one unit on top of the other. Others have a more detached feel but share structural elements. Developers often choose duplexes in suburbs where zoning allows two dwellings on one block.

In both cases, councils require specific approvals, especially if the plan includes subdividing the land or selling each side separately.

Pros and Cons for Buyers and Investors

Here’s a quick overview of the main pros and cons:

• Affordability: Semi-detached homes are generally more affordable than freestanding homes. Duplexes can offer even more cost-effective entry, especially with dual income potential.
• Control: Semi-detached homes usually offer full control over your property. Duplex control varies depending on title type.
• Maintenance: Semi-detached home owners are responsible for their own lot. Duplex owners in strata arrangements share responsibilities.
• Privacy: Semi-detached homes often have better privacy with only one shared wall. Privacy in duplexes depends on design.
• Investment Return: Semi-detached homes are reliable for long-term capital growth. Duplexes are attractive for dual income or split rentals.
• Stamp Duty: Semi-detached stamp duty is based on individual title. Duplexes with strata may incur slightly higher costs.

Pro Tip: If you’re planning to rent out both sides of a duplex, check local council rules around minimum lot sizes, car spaces and privacy screens. These often affect approval.

Planning Rules and Legal Differences

Local councils treat semi-detached homes and duplexes under slightly different planning guidelines. For instance, in NSW, a semi-detached dwelling often falls under low-density residential zoning. Duplexes, especially dual occupancies, might require medium-density zoning or larger lot sizes.

Subdivision rules also vary. You can usually subdivide a semi-detached property if it has a Torrens title. For duplexes, subdivision may need approval based on title type and council regulations. Always check with local planning authorities before buying or building.

Insurance is another legal difference. Strata-titled duplexes need a combined insurance policy managed through a body corporate. Torrens titled homes allow each owner to manage their own cover.

What to Consider When Choosing Between the Two

If you’re deciding between a semi-detached home and a duplex, consider the following:

1. Title type: A Torrens title gives you more autonomy.
2. Maintenance: Are you comfortable sharing responsibilities?
3. Long-term use: Will you live in one side and rent the other?
4. Zoning restrictions: Can you legally build what you want?
5. Resale value: What do buyers in your area prefer?

For investors, duplexes may offer better rental returns. Owner-occupiers may prefer the added privacy of a semi-detached home.

Comparing Costs in Sydney

Prices vary based on size, location and design. However, duplexes often come out more affordable, particularly for buyers wanting dual income potential. Here’s how median prices compare:

• Inner West Sydney: Semi-detached homes have a median price of $1.6M. Duplexes average around $1.3M. Semi-detached properties tend to offer more historic character.
• Western Sydney: Semi-detached homes average $950K, while duplexes sit at about $870K. Duplexes are particularly popular for investor-focused builds.
• Northern Beaches: Semi-detached homes reach a median of $2.1M. Duplexes come in slightly lower at $1.9M. Both property types are limited due to strict zoning rules.

Final Thoughts

A semi-detached house and a duplex may appear similar from the outside, but they differ in key ways. Titles, layout, ownership responsibilities and long-term value all depend on what type of property you choose.

If you’re looking for full ownership, fewer shared responsibilities and good capital growth potential, a semi-detached home may suit you better. If you want dual income or a home that supports extended family living, a duplex could offer more flexibility.

Always speak with a local property advisor or builder to understand your options based on council rules and long-term goals. Choosing the right property type now can help you build value and avoid future limitations.

For more inspiration, you can also visit Brooklyn Homes to view new designs and property types suited to your lifestyle.

‍