GRANNY FLAT SIZE GUIDE

Are you considering adding a granny flat to your existing home? Whether you aim to increase the value of your house, accommodate a growing family, or generate income from rentals, choosing the appropriate size for a granny flat is fundamental.

Granny Flat Size Guide: The rules limiting the size of granny flats can change depending on your local council. The minimal area that can be used to build a granny flat is typically 40 square meters. However, depending on your unique location and regional zoning laws, the maximum size allowed for a granny flat may range from 50 to 100 square meters.


There are methods to work around the local rules and keep expenses down if you want to construct a granny flat without going broke. In this talk, we’ll examine the optimal sizes for a granny flat’s bedrooms, bathrooms, and kitchens, as well as the typical length of a granny flat deck. We’ll also look at ways to make the most of the available space within the constraints of local regulations. Let’s dive right into it!

Understanding Granny Flat Regulations in Australia

Learn about the unique rules that apply to granny flats in Australia before taking into consideration design and making the most of the available space. State-by-state variations in these regulations are possible. Generally speaking, granny flats cannot be sold separately and must be constructed on the same lot as the parent home. Most Australian states limit granny flat interior dwelling space to 60 square metres. You should always check with your local government for exact rules in your area.

Purpose and Functionality

First and foremost, take into account the granny flat’s essential purpose. Is it for a young adult, an elderly relative, or maybe rental income? The function essentially determines how much space is needed:


For elderly relatives: Safety and accessibility are top priorities. Senior granny flats may require additional space for mobility assistance, larger bathroom fixtures for increased security, and a condensed floor plan to minimise the need for frequent moving.


For young adults or couples: These apartments may need modern, dynamic designs that accommodate busy lifestyles, such as areas for home offices, modest entertainment areas, and additional storage for personal belongings.


For rental purposes: It is necessary to maximise appeal to prospective tenants. A one-bedroom layout that separates the living and sleeping spaces can boost the property’s rental potential while offering residents privacy and a high standard of living.

Analysing Available Space

The size of the granny flat is largely determined by the size of your land. Enough room must be allotted for parking, gardens, and privacy barriers separating the main home from the granny unit. A property’s overall worth may drop, and its visual appeal may be diminished if overcrowded.

Adhering to Regulations

As previously stated, most Australian states and territories limit the internal living capacity of granny flats to no more than 60 square metres. These rules, though, can change. Always contact your local council to learn about local regulations and limits. By doing this, you can be sure your granny flat complies with the law and stays out of trouble.

Design Considerations for Optimal Size

To improve spatial efficiency, take into account the following design suggestions when determining the size of your granny flat:

Vertical Space Utilisation: When possible, choose loft designs with high ceilings. This gives the space a feeling of openness and, without increasing the footprint, adds more sleeping or storage spaces.

Integrated Outdoor Areas: Add decks or covered patios that extend the living area. This can give the impression that the granny flat is larger without exceeding size constraints, and it works especially well in Australia’s climate.

Flexible Layouts: Design adaptable interior features like fold-away beds, retractable walls, and modular kitchens to create spaces that may be used in various ways. These characteristics make a tiny room more functional by enabling people to change the area as needed.

How Big Should a Granny Flat Be?

Depending on your local council, the rules limiting the size of granny flats can change. You can use a minimum area of 40 square meters to construct a granny flat. However, depending on your unique location and regional zoning laws, the maximum size allowed for a granny flat may range from 50 to 100 square meters.

The size of a granny flat should be determined primarily by its planned use, the amount of available land, and the rules set forth by the local government. Selecting the appropriate size affects everything from building costs to future usability, and it is essential for striking a balance between comfort and functionality. The following are the main elements that affect the size of a granny flat so you can make an informed selection that satisfies your needs and requirements and conforms with laws.

-Victoria:

The maximum size for “Dependant Persons Units” (DPUs), which must be mobile, is typically around 60 square meters. Depending on your particular Council, there may be restrictions on size.

The Granny Flat Size Guide ranges from 60 square meters to 100 square meters in New South Wales. The former requires clearance through a Development Application, while the latter does so under Compliant Development.

– South Australia:

Granny flats may be up to 70% of the total floor area of the primary residence or 60 square meters, whichever is smaller.

– Tasmania:

Granny flats may not exceed 60 square meters in size or up to 30% of the size of the primary residence.

– Western Australia:

Depending on your local Council, the size may range from 70 square meters to 100 square meters. Rural places are typically more adaptable.

– Northern Territory:

In urban places like Darwin, granny flat sizes are usually limited to 50 square meters. However, under more permissive rules, some local councils in rural regions may allow up to 80 square meters.

The typical size restriction in the Australian Capital Territory is 90 square meters. Notably, the ACT also has a minimum size limit for granny flats of 40 square meters.

To guarantee compliance, it is advised to refer to your individual Council’s legislation for complete and current details on granny flat size restrictions in your area.

Optimal Granny Flat Sizes for Different Needs

1. Compact Granny Flats (20-35 square meters)

Compact granny flats are perfect for singles or couples who appreciate efficiency and simplicity. These small flats typically consist of a living and sleeping area connected with a kitchenette and bathroom. Some design options for these spaces include multipurpose items that maximise every square inch of available space, wall-mounted storage, and foldable furniture.

2. Granny Flats (36-60 square meters)

A typical granny flat is ideal for small families or people who require additional space for guests. It can have one to two bedrooms. These apartments often have a pleasant living area, a larger kitchen, and separate bedrooms. To improve these areas, consider adding lots of natural light, employing light colours to give the impression of more space, and creating unique storage solutions that are tailored to your needs.

What Size Should Granny Flat Bedrooms Be?

Determining the ideal bedroom size is one of the most critical issues in granny flat design. This decision affects the flat’s general layout and design and the living area’s comfort and usefulness. This section examines the best bedroom sizes for granny flats, considering a range of requirements and making the most of the available space.

There are no precise laws regarding the size and shape of Granny Flat Size Guide bedrooms in granny flats, allowing for diversity. It is absolutely possible to fit a double bed in a space that is less than the typical standard bedroom size of 3 meters by 3 meters. A granny flat bedroom serves as a personal space for usage, storage, and relaxation; as such, it should be designed to suit the needs and tastes of the owner-occupiers or tenants.

However, there are some fundamental specifications for bedrooms in granny flats, such as:

– Access Door:

There must be a working access door to enter and depart the bedroom.

– Electrical Fittings:

To enable proper lighting and electrical access inside the bedroom, adequate electrical fittings are necessary.

– Windows:

A bedroom must have windows that offer enough ventilation and natural light to meet the Building Code of Australia (BCA) requirements. The BCA recommends that the windows have a combined size of at least 10% of the floor area of the bedroom, with a 5% minimum requirement for ventilation.

To enhance safety and facilitate early detection of potential fire hazards, you must install smoke alarms in each granny flat bedroom, adhering to BCA standards.

Also, keep in mind that anything less than:

It can be challenging to accommodate a double bed’s size while providing enough egress (the exit) space in a granny flat bedroom. To design a plan that works, it’s essential to consider every possible furniture configuration. One critical criterion is to leave at least 700mm between spaces to enable easy movement. This design factor makes sure that:

– The position of the bed and nightstands does not hinder exits or door openings.

After accounting for these considerations, you arrive at a total space need of 2.77 square meters. A bedroom that is smaller than this becomes quite cramped for a double bed, making it challenging to enter and exit. Such small quarters might aggravate tenants and even influence your rental income.

Ideal Bedroom Dimensions

A granny flat’s bedrooms might differ in size based on several factors, such as the overall unit size and the planned number of residents. A well-designed bedroom should have enough room for a bed, necessary furniture, and mobility to provide comfort without going overboard.

Single Bedroom: For a granny flat intended for one person, a bedroom size of about 9 to 10 square meters typically suffices. There is enough room for a single bed, a nightstand, and a wardrobe in this area to be functional without discomfort.

Double Bedroom: Consider a bedroom at least 12 square metres in size if the granny flat can house a couple or is meant for rental markets. This space has enough room for a double bed, several pieces of furniture, including bedside tables, an enormous closet, and two people’s worth of circulation.

– Master Bedroom

If the granny flat is intended to be long-term or more luxurious, the master bedroom may include an attached bathroom. In this scenario, aim for a minimum area of 15 square metres, which allows room for a giant bed, ample storage options, and extra comfort features.

(12.25 square meters, including built-in wardrobe and ensuite) – 2nd/ 3rd Bedroom** (9 square meters) – 4th Bedroom (7.84 square meters, frequently used as a study)

Additionally, although wardrobes are not always necessary in bedrooms, tenants typically anticipate them. To improve the aesthetics and usability of the living area, think about installing built-in cupboards in all of your bedrooms, including those with space-saving features. 

Space-Efficient Design Tips

Efficiency in design is especially crucial in smaller places, such as granny flats. The following advice will help you maximise the space in your bedroom:

• Built-in Storage: Using overhead storage cabinets and built-in wardrobes to conserve space. These solutions keep the space neat and open, better than heavy, standalone furniture.  

• Multi-functional Furniture: Choose beds that can be folded up when not in use or wall beds with built-in storage underneath. During the day, these solutions free up floor space and offer flexibility.  

• Strategic Layout: To maximise available floor space, position the bed up against the wall. Ensure the windows are oriented to allow natural light to flow through them, enlarging and brightening the space.

What Size Should Granny Flat Bathrooms Be?

There are usually no complex rules about the size of a bathroom in a granny flat, but it is recommended to be at least 2 meters by 2 meters to fit all necessary fixtures comfortably. The bathroom’s floor area must allow for:

Shower Cubicle: Shower cubicles are typically 900 × 900 mm in size, though more space-saving variants are available.

Taking into account two important variables, one calculates this maximum height:

• Vanity Unit: Additionally, you’ll need space for a vanity unit.

Effective use of space is essential in smaller bathrooms, which are frequently 1.5 by 2 meters in size (equating to 3 square meters).

However, if money and space permit, you can choose a larger bathroom with measurements like 3.2 x 2.5 meters (equivalent to 8 square meters). Such a spacious bathroom might not be necessary in a granny flat, but it can be a luxurious addition, providing a relaxing atmosphere. This larger space can be especially beneficial if you’re planning the granny flat as a teenagers’ retreat or if you want to create a more spacious and comfortable environment for occupants.

Determining the Right Bathroom Size

The total size of the apartment, the number of residents, and any special needs like luxury or accessibility requirements all affect how big the bathroom in a granny flat is. The following lists typical bathroom designs along with their recommended sizes:

Standard Full Bathroom: usually consists of a toilet, sink, and tub/shower combo. For these components, a space of roughly 5 to 6 square metres is usually sufficient for pleasant use and enough room for circulation.

Three-Quarter Bathroom: A three-quarter bathroom with a sink, toilet, and standalone shower (no tub) might work well in a small space. This kind can easily occupy 4 to 5 square metres of space.

Half Bath (Powder Room): A half bath with just a sink and toilet may be adequate for granny flats used as extra living space or for guests. A smaller space of roughly 2 to 3 square metres is sufficient for these projects.

Design Tips for Efficient Bathroom Layouts

Clever design techniques are needed to maximise space when designing bathrooms in granny flats. The following advice can help you create a bathroom that is both practical and aesthetically pleasing in a small space:

Wall-Mounted Fixtures: Select wall-hung toilets and floating sinks to free up space on the floor, which will enlarge the bathroom and make cleaning easier.

Sliding Doors: To reduce room, install sliding doors instead of standard swinging ones. This works particularly well in small restrooms when every square inch counts.

Large Mirrors: A giant mirror installed in a bathroom can visually double the size, improving light and giving the room a more airy, open sense.

Light Colors and Good Lighting: Paint walls and tiles in light hues to increase light reflection. A small bathroom must have enough illumination to feel airy and comfortable.

What Size Should A Granny Flat Kitchen Be?

Although the size and requirement of a Granny Flat Size Guide of a kitchen in a granny apartment are frequently unrestricted, it is advised to have at least 3 meters of bench area to fit standard appliances easily. Additionally, not all granny flats need kitchens.

Typically, the kitchens in traditional house plans measure about 3.2 × 4 meters or 12.8 square meters. If money or room are issues, though, you can choose a much smaller kitchenette.

A separate kitchen may not be required if a family member lives in the granny flat and can use the kitchen in the main house. However, adding a kitchen or kitchenette would improve the granny flat’s charm and usefulness if you plan to rent it out.

In many people’s houses, the kitchen retains a special place because it’s a popular living room area. If you’re looking for motivation or suggestions for granny flat kitchens, reading related articles can be helpful.

Whatever style you decide on, your kitchen or kitchenette should adhere to the following standards:

– Windows: Ensure the kitchen has windows for proper ventilation and natural lighting.

– Ease of Access: To increase efficiency, reduce the distance between the sink, stove, and refrigerator.

– Space to Move: Keep enough room for walking to avoid feeling crowded when using the kitchen.

– Optimize Work Surfaces and Storage: By maximising the use of work surfaces and storage spaces while reducing the use of floor space, you can create a kitchen or kitchenette that is both useful and well-organized.

Average Size of a Granny Flat Roof

Most authorities often impose height limitations on granny flat roofs, with a maximum permissible height of 8.5 meters, to ensure compliance with laws. It’s crucial to realise that the roof space differs from the floor area, and having a bigger roof doesn’t affect the necessary eaves below.

Taking into account two important variables, one calculates this maximum height:

– Distance vertically from the existing ground: This explains the height of the building from its lowest point to its tallest point.

It does not, however, include some buildings, such as:

Masts, chimneys, flues, satellite dishes, antennas, communication equipment, flagpoles, and other related elements

It’s important to remember that further restrictions, such as setbacks, may apply when the granny flat’s height surpasses 3.8 meters. It is important to consult the pertinent resources and rules given by your local council for more precise and extensive information regarding granny flat height restrictions.

Average Size of a Granny Flat Deck

A clever approach to increase your granny flat's legal maximum floor area is to add a deck to it. This implies that you are not limited to the rules put forth by your local council, and your deck can be rather large if you follow the detailed regulations stated by your council.

You can legally add other constructions to your granny flat to expand its size. Your primary deck incorporation restrictions will likely be your budget, setback requirements, and available yard space.

Typically, a deck will be roughly 30 square meters in size, greatly expanding your Granny Flat Size Guide outdoor living area. Your prospective living space might increase from a constrained 60 square meters to a more generous 90 square meters, providing plenty of space for leisure and pleasure.