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Dual Occupancy Home Designs

Dual Occupancy Home

This type of dual dwelling is classified into two categories; attached and detached. Attached dual occupancies are two dwellings on one lot of land that are attached to each other, while detached are two separate dwellings on one lot of land. Neither of these include a secondary dwelling. A dual occupancy cannot be subdivided; however, utilities can be separated between the two dwellings.

Dual occupancy home designs rose in popularity during the 1920s and 1930s and were designed to resemble a single-family house and blend into the streets they were being built in. This was a conscious strategy by city planners aimed at maintaining property values by giving the street a consistent appearance. Since then, however, dual living has evolved into a cost-effective and practical housing solution.

Dual occupancy homes tend to attract a number of different types of buyers, including people who want to live in one of the dwellings and passively earn income off leasing the second dwelling. They also attract families with older children or elderly parents, so they are able to stay close by while maintaining the independence of their own dwelling. 

Dual occupancy designs are ideal for when a block cannot be subdivided, but you still want two dwellings on the single property, as it still provides many of the benefits of subdividing and allows for two self-sustaining dwellings.

What are the benefits of a dual occupancy design?

A dual living solution can be the best option for your home design as it is incredibly versatile with plenty of applications. Dual occupancy home designs come with many great advantages for first home buyers, builders, investors, and families looking for extra space. They can provide an excellent opportunity to offset your mortgage and earn a passive income if you live within one of the dwellings while renting out the other. 

There are a number of financial benefits of dual occupancy homes designs, including building equity, since when dual occupancy properties are built under strata title it allows the two dwellings to be valued as two separate homes. This means they will be able to be sold separately and create instant equity from the growth in the original properties value. 

They also provide the opportunity for supplementary income, as the second dwelling can be rented out full time or used as an Airbnb. Of course, even more income could be generated if both dwellings were rented out and you had elsewhere to live yourself. By using this rental income, it also provides the opportunity to pay off your mortgage sooner, along with several tax reductions often available with dual living house plans.

They are also a great option for extended family members, providing a great housing solution for elderly or disabled relatives as well as adult children. Duplexes allow for increased independence while still living on the same property.

Dual Occupancy Council Regulations

The main drawback of dual occupancy home designs is that every council in Australia has different regulations and restrictions that need to be adhered to. Council requirements for dual occupancy vary greatly in different areas and states in Australia, meaning there is no standard block size, shape or plan that will guarantee approval across all locations. There is unfortunately no one size fits all choice for choosing the right land size for your dual living development. 

Dual occupancy development must be permitted in its specific Council land zoning area and obtain development consent from the Local Council by complying with certain planning controls. 

The first consideration is if dual occupancy homes are permitted at all within your zone. If they are, they still then need to comply with other planning controls in the Local Environmental Plan (LEP) and Development Control Plan (DCP). The main requirements include a minimum site area and a minimum site width specified by your local council. Some other controls include maximum floor space ratio, maximum building height, building setbacks, car parking, open space, and minimum landscaped area. 

Each state in Australia has greatly varying regulations for dual occupancy developments summarised below. 


  • The Sunshine Coast, Toowoomba, & Scenic Rim councils allow dual occupancy house plan constructions throughout their local government area (LGA).
  • Dual occupancy development is also allowed in Ipswich City (within the Western suburbs), Logan City (within the southern suburbs), and Moreton Bay (within the Northern suburbs). 
  • Within Brisbane City and the Gold Coast, dual occupancy homes can only be constructed under certain conditions.
  • Many Queensland councils only allow for the second dwelling in a dual occupancy home design to be one-bedroom and no larger than 48m2.
  • Other councils in Queensland only permit dual occupancy homes if they share one main entrance, with the provision of two further private entries once inside.

New South Wales 

  • Properties located in R2, R3, R4 or B1 zoned areas are approved to have dual occupancies built on their land.
  • Under a new code that applies to properties zoned R1, R2, R3 and RU5, blocks must be either 400m2 or the minimum lot size required by council, whichever is larger.
  • Blocks also need to be a minimum of 12 metres wide and buildings must have a minimum side setback of 0.9 metres.
  • The code also requires each dwelling to be at least 5 metres wide, face a public road, and cannot be located behind a separate dwelling (except on corner lots).
  • Off-street parking must also be provided for at least one car per dwelling.


  • There are three main new residential zones in Victoria that all generally allow dual occupancy development.
  • General Residential Zone (GRZ) allows moderate growth in housing development with buildings up to 10 metres in height.
  • Residential Growth Zone (RGZ) is the most development friendly zone and located close to principal transport infrastructure or larger retail areas and contain developments consisting of apartments and units generally four storeys or 13.5 metres high.
  • Neighbourhood Residential Zone (NRZ) is more restrictive with dual occupancy developments and the allowances for lot sizes are made at the discretion of the council.
  • For every zone consideration must be made for site constraints, size, width, crossover location, and orientation.

Western Australia

  • Ancillary dwellings in Western Australia need to have a lot size of at least 450m2 and parking provision needs to be allowed for.
  • There can be many local planning policies additional to WA state policies that can affect minimum areas and street frontage facades that need to be checked at a more granular level.

Australian Capital Territory

  • In the ACT zoning rules for RZ2 blocks of 800m2 or larger allow you to build two houses on the same block that can then be sold off as separate deeds.
  • Some blocks have a reduced minimum size of 700m2 that were surrendered under the Buyback Program.

South Australia

  • The following guidelines are usually required for acquiring development approval in SA:
    • An additional dwelling should be compatible with the setbacks of buildings on adjoining land and other buildings in the locality.
    • A dwelling should be sited and designed to incorporate adequate private open space.
    • Every dwelling should be provided with one covered and one uncovered park.
    • A two-storey dwelling should consider protecting the privacy of adjoining properties. Designs should ensure that no proposed balconies have direct view into the rear and side yards of adjoining neighbours and contain screening to a minimum height of 1700mm above the level of the floor. Any windows, which will constitute an overlooking problem, will be required to comprise fixed obscure glazing to a minimum height of 1700mm above the level of the floor.

Northern Territory

  • The minimum lot size on which dual occupancy development could occur is proposed as 800m2, with each resulting dwelling requiring a minimum lot size of 400m2.
  • Any dual occupancy development would need to meet the general requirements of the NT Planning Scheme and Local Government Subdivision Guidelines, including provisions around setbacks, storm water drainage, landscaping, parking requirements and essential services.

Despite the difficulties many people face with what can be very specific and challenging local council restrictions, dual occupancy home designs are a popular choice in some areas. In Sydney particularly, dual occupancy is becoming increasingly popular while other areas also have large demand but outweighing difficulty to get plans approved by council. The popularity in Sydney is because the value of land is so high, causing people to strive to get as much value from their property as possible.

COVID19 also has influenced dual occupancy and its relative popularity. There has been a noticeable change in families going for a more lifestyle focused, premium product with less focus on maximising return on investment when building a house. People are looking more and more to build houses that reflect the way they want themselves and their family to live, rather than the houses future value. This has directly caused the popularity of dual occupancy homes to go down overall in Australia, due to COVID19 and lockdowns placing greater societal importance on time spent in the home. 

This is despite the trend of older children moving back home and elderly parents moving in with their kids. Instead of looking to move into traditional dual occupancy living scenarios, they are embracing a new way of intergenerational living, where people are living in one large house where there are two master bedrooms, one on each floor with their own ensuites – allowing everyone their own space while still sharing the overall home. 

This also comes with the added benefit of single homes like this not needing to go through the same council approval processes as dual occupancies, which normally take 12 months to go through council. Traditional homes will become more popular after COVID19, with people desiring big lifestyle houses and more homeowner grants being passed through government. 

G.J. Gardner has a number of dual occupancy home designs available; however, these may also need to be adjusted to meet the regulations of your zone.

Check out our range of Dual Home Designs!

Essendon 200Yarraville 206Chadstone 203

64 Essential Questions to Ask Any Builder

Before you sign a contract or pay a deposit, ask your builder the following questions. It could potentially save you thousands and avoid costly legal bills.

Deposit and Pricing Questions

Once your plans and detailed specifications are finalised, a reputable builder will prepare a contract. The contract should set out both parties’ responsibilities, and importantly, a progress and payment schedule.

  1. How much is the deposit and how much will be kept should we not proceed?
  2. At what point will we have the final price?
  3. Can you give us a price before we pay a deposit?
  4. If we pay for things like soil test and property information, do we get these reports to own should we not proceed?

Land Questions

Finding the right block of land for your new home is an important decision. There are a number of considerations when choosing the size and location of your land to ensure you can build your dream home.

If you agree to pay for preliminary information like a soil test, property report and levels, you should ask your builder the following questions. If the answers to any of these questions is ‘yes’, you will need to obtain a cost for each that will likely sit outside standard inclusions.

  1. Do I require an engineer-designed foundation? (You may require this if your block is on reactive soil or close to the coast.)
  2. Do I require protection against termites?
  3. Does the storm or septic water disposal system need to be engineer-designed?
  4. Are retaining walls likely to be required?
  5. Will there be soil/fill that needs to be taken away or brought onto the site?
  6. Will there be services required to receive distant connections?

Plan & Design Questions

  1. How many plans do you have in your range?
  2. Can I modify your standard plans and at what cost?
  3. Can I bring in my own plans for you to price?
  4. Will you inspect our block before we buy it to ensure it’s suitable for the kind of house we want to build?
  5. What is included in your floor area total? (The square metre area of a home can be measured in different ways. Some builders could include decks, eaves, patios or paved areas.)
  6. Will you provide a comprehensive design consultation service? What will this include?
  7. Will you provide modern visual design aids and access to professional designers to help me achieve the ideal plan that I want?
  8. Will you help me to find out if there are specific requirements or restrictions regarding our home’s location on our block, and are there any protective covenants?
  9. Will you give me a simple concept plan with my quote before I pay my deposit?
  10. What energy rating will my home be aiming to achieve?
  11. Where will the midday winter sun enter the house?
  12. How much summer afternoon sun is going to enter the house?
  13. Where will the view (if any) be visible from inside?
  14. Are there long runs for the hot water and if so how will wastage/lag time be reduced?

Standard Inclusion Questions

  1. Is your quote comprehensive in its inclusions?
  2. Can you explain what is not included?
  3. What soil classification is allowed for in your standard inclusions for foundation and slab design? (Some builders often treat even simple excavations and earthworks as extras.)
  4. Will my colour selections be carried out locally?
  5. What heating and cooling is included?
  6. What floor coverings are included?
  7. Do you have a soil test allowance in your standard inclusions?
  8. Does the contract or quote include any provisional sums? (These costs could potentially be a guesstimate that are not fixed and will change once they have the final price from their supplier.)
  9. Have you included full drainage and other service costs or have you listed them as a provisional sum? (This could potentially be listed as a provisional sum which could rise considerably.)

Credibility Questions

  1. Are you trade certified and affiliated to a recognised industry body such as HIA/MBA?
  2. Can you show me through any homes that are currently being constructed, or any completed homes? (Here you can check the quality of workmanship of existing customer homes.)
  3. Can you provide me written testimonials from past clients?
  4. Is it a fixed build time?
  5. Will you pay me money if you are over contract time? (This is also known as liquidation damages.)
  6. What exceptions enable you to extend the contract time with no liquidations damages payable?

Confidence Questions

  1. What health and safety processes do you have in place?
  2. What contractors do you use?
  3. Do you have a dedicated construction coordinator who will personally manage all sub-trades on my site, keep me informed of progress and answer my questions?
  4. Can I speak directly to the registered builder who’s ultimately responsible for my home construction?
  5. How can I be sure your company is financially stable?

Guarantees Questions

  1. Who does the builder acquire home owner warranty insurance from?
  2. Does this insurer cover loss of deposit, non-completion and defects?
  3. Does the builder have min $10 million dollars public liability insurance, and construction insurance adequate for your home?
  4. What is the maintenance period?

Technical Questions

Although many of these questions are technical in nature, it can be beneficial to have responses so that you can accurately compare quotes.

  1. Is the supply of concrete pumping included?
  2. What wall and ceiling insulation is included?
  3. Is a three coat paint system included? Using whose paint?
  4. Is sarking to roofing included?
  5. Are COLORBOND® down pipes included?
  6. Are eaves standard on our chosen design?
  7. What type of toilets and basins are included? Are they china?
  8. Is obscure/safety glass to ensuite and bathroom included?
  9. Are there plan-specific overhead cupboards to kitchen included?
  10. Is a gas (electric in some areas) boosted solar hot water system with two solar panels included?
  11. Is the rangehood ducted to natural air i.e. not recirculated?
  12. Is termite treatment included and what system is used? Will maintenance be required??
  13. Is trenching and conduit for service connections included?
  14. Is ceiling plaster fixed onto metal battens, reducing the risk of warping and cracking?
  15. Are steel lintels with bricks over the garage and windows included i.e. no high maintenance timber in-fills?
  16. At what stages will you be able to inspect the works?

Two Golden Rules

Finally, there are two golden rules to follow when dealing with builders.

First, do not sign anything with your builder until you have read all the fine print. If there is anything that you do not understand, ask for advice from an independent builder, consultant, or obtain legal advice. Remember once you have signed a building contract you cannot normally back out if you change your mind. There is no ‘cooling off’ period.

Second, ensure that everything important is confirmed in writing and keep a copy.

Looking for a builder in your area? Contact your local G.J. Gardner Homes office.