How much land do you need to build 2 houses on one property?

by | Apr 12, 2023 | Building new, Building tips, Land

With increasing land prices and rental demand skyrocketing, dual occupancy is becoming a more popular option in the Australian market. Dual occupancy is where more than one inhabitable home exists on one block. Some of the most common examples of dual occupancy include duplexes, granny flats and subdivisions The great news for home buyers is there are a few options when it comes to dual occupancy. So if you’re looking to build multiple dwellings on a single plot of land, you’re in the right place. We’re looking at how much land you need to build 2 houses and what options are available on the market. This article will look at all the pros and cons of each design to help you make an informed decision.

Types of dual occupancy homes to consider.

When it comes to dual occupancy, you have many options to consider, whether it’s a second dwelling to your existing house or two living spaces that share a common property. Each has its pros and cons and the best option for you, so let’s take a look at the most common options.

Granny flats

Granny flats are separate, habitable dwellings built on the same land as a main building (in this case, your house). In legal and council guidelines, a granny flat is often referred to as a second dwelling. Although known for being a popular option for older relatives (hence the name), the humble granny flat offers a wide range of options for a homeowner from accommodation to adult children to a rental space for tenants.

There are a few general rules when it comes to granny flats including:

  • According to the Brisbane Council website, the maximum size a granny flat can be is 80m2
  • You must provide a parking space for your secondary dwelling along with one for your home.
  • Your secondary dwelling needs to be located within 20 metres of your main dwelling.



Granny flats are a space that can be used for a variety of purposes. Along with long-term accommodation, granny flats make fantastic guest rooms and Air BNBs. Once your children have moved or you’ve decided to stop renting, a granny flat can easily be converted into an amazing home office, entertainment area, home gym or whatever your imagination can think up.

Great Rental opportunity

A granny flat is ideal for renting purposes. A granny flat offers your tenants more privacy than simply renting out a room in your home. Queensland has recently relaxed its guidelines when it comes to renting out granny flats to non-family members, so it’s now easier than ever to get a tenant.

Adds to Property Value

The benefits listed above translate into the property market. A granny flat is a great feature to have up your sleeve when it comes to selling and attracting interest. The better designed your granny flat is, the more it’ll add to your property value.

No Planning Approval Required

This doesn’t mean there aren’t rules and guidelines you need to meet. However, so long as your proposed granny flat meets the requirement laid out in the Dwelling House Code.

You will need to submit a development application if:

  • your planned secondary dwelling is going to be larger than 80m2.
  • the granny flat will be further than 20m away from your home.
  • your plans in any way don’t meet the Dwelling House Code.

If you’re still unsure if you’ll need local council approval, you should speak to a town planner or building certifier to confirm whether you’re okay to go ahead with your build.


Can only be a certain size

While this won’t be an issue for most people, a granny flat would be a tight squeeze for a larger family.

Second home on the same land

Ever wondered if you can build two houses on the same property? Building more than one house on a single property is possible, however, you’ll need approval from the council before this can go ahead. If the second house is 80m2 or less, it’ll be considered a granny flat or second dwelling to your existing home. Your best options include a duplex home or a granny flat.


Save on Land Costs

Depending on where you buy, a block of land can be a very expensive proposition. Not having to purchase two separate blocks can save you a small fortune.

Great way to keep family close

Multigenerational living is more popular than ever these days, and a second home provides that closeness without forgoing independence.

Excellent renting opportunity

Any Dual occupancy provides a fantastic chance for rental income, especially if you’re in a desirable location.


Will need to meet council conditions

This isn’t necessarily a con, but the number of council regulations you’ll need to meet will immediately rule some people out of this often

  • Minimum lot size that can enable a subdivision to occur.
  • The minimum setbacks from boundaries
  • Council will specify a minimum amount of open space between both dwellings
  • Height restrictions on the dwelling to be built

Duplex Homes

A duplex is a residential home that contains two separate homes that connect through a central wall. Floorplans can vary whether the homes are side by side one in front of the other. We personally prefer side-by-side duplexes as this means no one has to walk by anyone else’s windows just to get home. Duplex homes offer a few options, including personally settling one house for yourself and selling/renting the other, rent both homes.


Great renting option

With a duplex home, you start making a profit almost immediately by renting one or both houses out. Unlike other rental properties, you have the opportunity to double your profit. In the right location with a little luck, a duplex can be a financially secure investment.

Save Money

A duplex building will cost less than building two separate homes, not to mention the extra costs that come with purchasing two blocks of land.

Good resale options

With a duplex, you can sell the title to one of the houses if you wish or even both. Duplexes are popular due to the high demand for housing.

Various ownership options

With a duplex, you have a few options when it comes to ownership. You can either have one title for the entire building or separate titles for each house.


Close Proximity to neighbours

If you’ll be living in one of the houses, you’ll obviously be fairly close to whoever’s living next door. This could cause problems if one of you likes to spend their evenings reading and the other partying to loud music. For those renting to strangers, a little diligence, patience and research will ensure you rent to someone with whom you can enjoy a harmonious living arrangement.

You’ll need a tenant for Dual occupancy to be profitable

It might seem obvious, but a rental property only makes an income if someone is renting it. While the property is empty, you might take a loss through maintenance and expenses. This is a risk for any rental property.

Dual Occupancy Subdivision

A dual occupancy subdivision is when you subdivide your current block of land to create a new lot at the back of your property. On this new lot, you can build a new home. Whether you’re able to do this will depend on factors such as your zone, neighbouring planning controls and whether your local council will permit it.


Potentially higher profits

For renters or investors, subdivisions could potentially increase the performance and profitability of your investment. Splitting the land in two could also give you the option of building your dream home and selling the other lot for a quick profit. Research and sound advice should be taken onboard to make sure this is a savvy move.

A quick way to add to your property portfolio

Building a property portfolio isn’t easy, but two lots of land allow you the flexibility to build different types of buildings, diversifying your portfolio in the process. When done well, this could improve future performance.


Is only viable on certain blocks of land

As you can imagine, smaller or narrow lots are simply not going to have enough space to be subdivided into multiple blocks

Requires a lot of approvals

Creating a new block and title isn’t something you can DIY. You’ll need to work with the council and hire surveyors to determine just whether a subdivision is a plausible idea.

Could backfire and reduce the value of large property

Depending on the property and where it’s located, the best long-term move may be to not subdivide. While subdividing could lead to a short-term gain, the value of a large block of land shouldn’t be underestimated, especially as block sizes are getting smaller. Like any development choice, you need to have a long-term vision and not let short-term gain overshadow the big picture.

Why consider building 2 houses on one property?

No building project is a small decision, and there are a lot of factors to take on board. There are some important considerations to take on board when building dual occupancy.


Few things are as important as our family, and more people than ever are choosing multi-generational living situations. Whether adult children are living at home while they save for their own house, or elderly relatives living closer while maintaining independence, dual occupancy is an ideal way of keeping family close under the same roof.

Renting opportunities

The rental market is booming at the moment and in the right locations, there will be always someone looking to rent. Though the rental market is doing well, it doesn’t mean dual occupancy is foolproof. For starters, you’ll need to build in a desirable location to attract potential purchasers. Desirable elements could include:

  • Close proximity to public transport, shopping centres, schools, and facilities
  • Well-regarded, friendly and safe neighbourhood.
  • A functional, well-maintained home.
  • A fair, reasonable price

Steady Rental Income can help with mortgage payments

Having a steady income from a rental can help cover the costs of your new home, including any mortgage or loan repayments. If you’re building the home in conjunction with whoever’s living in the second house, you can both contribute to paying back the costs of building the home.

Businessman hand giving money – Australian dollars

Save money on land

Land is in high demand and is rarely cheap, and two properties are an expensive proposition. This isn’t even taking into account extra expenses like soil tests, stamp duty, surveying, council rates, insurance premiums and more. Dual occupancy is a way to provide accommodation for more people for the price of one block of land.

Add Value to Property

With the right approach, dual occupancy can potentially draw a higher price in the market. A dual occupancy home usually has a comparatively higher resale value than a rental property. With a subdivision or a duplex, you also have the opportunity to sell two new properties instead of one. Potential purchasers can be attracted to the renting potentials of dual occupancy, or the chance to live close to family.

Key considerations before building 2 houses on one property

As is the case with any building project, there will. You will need to take at least the following into account when building two houses on an existing lot.

Council approval

For a project, this size, council conditions and regulations need to be taken into account. Every choice you make regarding your floorplan will need to meet council guidelines and there can be serious consequences for those who don’t follow them.

Lot size restrictions

The size of your lot will play a major role in what the council is likely to approve on your block of land. A block size of at least 450m2 is ideal when trying to build two separate buildings, however, a duplex home can fit on even narrow blocks.

Regulations for the distance between each house on a lot of land

When it comes to building two dwellings on your property, your local council will have guidelines as to how far apart your buildings can be. You may be able to get an exemption, but this will require you to submit an application.

Land orientation

With the possible exception of granny flats, for most dual occupancy designs council will be interested in how the block of land falls. This will indicate where rainwater will run off to drain, as the runoff must be collected and removed through a stormwater easement. You’ll need to check whether it is physically possible to install an easement on your block of land.

Our tips for finding a builder to build 2 houses on one property

When choosing the right builder for your dual occupancy, here are a few tips to get you started:

  • Look for builders who specialise in what you want. Builders who have completed similar projects to yours will have the know-how to approach your build, and the experience to handle and potential complications.
  • Find builders who know your area.
  • Check if your builder specialises in blocks of land like yours, especially if it’s on a sloping block, narrow lot, or any unusual property.
  • Talk to Buildi. We know builders and can find someone to suit your project.

Get free advice from an experienced building broker

Looking for free, impartial advice on your next build? Whether you’re looking at building a dual occupancy house or any type of home, Buildi can help you during your building journey. From organising due diligence to ensure you don’t purchase a block of land that’s a lemon, to finding the perfect builder for your project, we can help you during every step of your building journey. We know all the tricks of the housing game and can ensure you avoid all the common mistakes, potentially saving you thousands of dollars. So get in touch today to find out more about how Buildi can assist you.

Book your free, impartial consultation today!


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