When drawing up a floor plan, you will need to know what size rooms should be for health, saftey and amenity. Although there aren't always any exact answers to the size of some rooms in a house, I will list dimensions for certain rooms that I find to be the bare minimum for comfort. There are however requirements on the ceiling heights for certain room types that I will list too. The height requirements are set out in the Building Code of Australia (BCA) which is now called the National Construction Code (NCC)
Click on Room Type Below to Jump to Detailed Design Information:
►Toilet ►Bathroom ►Laundry ►Bedroom ►Study/Home Office ►Living/Lounge ►Kitchen ►Stairs
Required Facilites
In a Class 1 building - a house, certain facilties/rooms are required in Australia as per BCA Part 3.8.3.
These rooms that are required are:
3.8.3.2 Required facilities
(a) A Class 1 building must be provided with-
(i) a kitchen sink and facilities for the preparation and cooking of food; and
(ii) a bath or shower; and
(iii) clothes washing facilities, comprising at least one washtub and space in the
same room for a washing machine; and
(iv) a closet pan and washbasin.
(b) If any of the facilities in (a) are detached from the main building, they must be set
aside for the exclusive use of the occupants of the building.
Room Types
In the BCA, there are rooms deemed: habitable rooms, and non-habitable rooms.
Depending on the class, depends on what requirements apply to that room.
Habitable rooms are rooms such as:
a bedroom, living room, lounge room, music room, television room, kitchen, dining room, sewing room, study, playroom, family room, home theatre, and sunroom
Non Habitable rooms are rooms such as:
a bathroom, laundry, water closet, pantry, walk-in wardrobe, corridor, hallway, lobby, photographic darkroom, clothes drying room, and other spaces of a specialised nature occupied neither frequently nor for extended periods.
Note: When I refer to door sizes, I am not talking about th opening size required. For example, an 820mm wide door needs a 900mm opening. The frame we allow for is 40mm on either side of the door.
ROOMS
Toilet / WC
A toilet or WC (water closet) is referred to in the BCA as a sanitary compartment in Part 3.8.3.3.
The requirements of a sanitary compartment in this section state:
The door to a fully enclosed sanitary compartment must-
(a) open outwards; or
(b) slide; or
(c) be readily removable from the outside of the compartment,
unless there is a clear space of at least 1.2 m between the closet pan within the
sanitary compartment and the nearest part of the doorway.
The reason behind this is that if some medical emergency arose where someone was locked inside the sanitary compartment (toilet), access would be needed to reach that person.
In older style homes before this requirement for instance, there wasn't enough space to gain access if someone fell behind the door and was unable to move to allow access for assistance.
Having an outward swinging door enables access even if someone fell behind the door.
Sliding doors too allow access as someone falling won't impede access to them.
The other alternative is removable hinges which I presonally don't like the look of.
It is also possible to have an inward swinging door, as long as there is enough room to gain access to the person in the sanitary compartment. In the above requirement, that distance is 1200mm from the face of the toilet pan to the door.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| Recommended no less than 900mm wide. | Preferably at least 1800mm long. Minimum recommended no less than 1500mm long. |
Minimum Required 2.1m. Recommended 2.4m. |
 1500mm x 900mm This is a sanitary compartment with a door swinging outwards. |
 1800mm x 900mm This is a sanitary compartment with a door swinging outwards. |
 1800mm x 900mm This is a sanitary compartment with a sliding cavity door. |
DOOR SIZES:
In terms of door sizes to the sanitary compartment, I personally always try and stay with an 820mm wide door. But if the need arises, I would go as low as a 720mm wide door but wouldn't recommend any less.
VENTILATION:
Something you may have noticed on the example plans above is that there is no window shown to the room. It is not a requirement to have a window, but if you do not have natural ventilation (such as a window), mechanical ventilation is required by the BCA in Part 3.8.5. (too much info to list all the part here)
LIGHTING:
Sanitary compartments are required to be fitted with artificial lighting if natural lighting as per Part 3.8.4.2 is not met.
Bathroom
All Class 1 buildings are required to have at least either a bath or shower. In many cases in new home today, they have both. I think having a bath is important as many people are put off by houses that don't offer this. It's always easy to add a shower over bath, but not as easy to include a reasonable sized bath tub if the room hasn't been designed to take one. You can get square baths, but in my opinion, they are really far from offering the qualities of a full sized bath in terms of comfort and space.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| Refer to plans for minimum dimensions. Although these are the minimum dimensions I would use, I would recommend making rooms bigger if possible so they don't feel cramped. |
Refer to plans for minimum dimensions. Although these are the minimum dimensions I would use, I would recommend making rooms bigger if possible so they don't feel cramped. |
Minimum Required 2.1m. Recommended 2.4m. |
 1800mm x 2400mm Simple shower, toilet and basin. |
 2400mm x 2400mm Toilet, bath (possibly with shower over) and basin. |
 2400mm x 2400mm Shower, bath and basin. |
 3300mm x 2400mm Toilet, shower, bath and 2 basins. |
In all these cases where there is a shower, I have used the dimension of 900mm x 900mm. I would recommend this as the minimum size.
The baths are shown as 1500mm long in these plans. This is really the minimum size of a bath tub length. I would really recommend though a bigger bath of
1675mm or greater to be able to stretch out more fully. Also note that the size of bath tub lengths varies between manufacturers and some are making the smaller size 1525mm. So be aware of the dimensions of your chosen bath before committing to a room size. It is always good to add a litte extra to the room size to allow for plasterboard and tiling.
DOOR SIZES:
In terms of door sizes to the bathroom, I personally always try and stay with an 820mm wide door. But if the need arises, I would go as low as a 720mm wide door but wouldn't recommend any less.
LIGHTING:
Sanitary compartments are required to be fitted with artificial lighting if natural lighting as per Part 3.8.4.2 is not met.
Laundry
All Class 1 buildings are required to have at least clothes washing facilities, comprising at least one washtub and space in the same room for a washing machine. This is usually placed in the room we call the laundry.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| Refer to plans for minimum dimensions. Although these are the minimum dimensions I would use, I would recommend making rooms bigger if possible so they don't feel cramped. |
Refer to plans for minimum dimensions. Although these are the minimum dimensions I would use, I would recommend making rooms bigger if possible so they don't feel cramped. |
Minimum Required 2.1m. Recommended 2.4m. |
 2100mm x 1800mm Basic laundry. 650mm wide space allowed for washing machine with dryer over. Doors are 820mm wide. Laundry trough in bench. |
 2100mm x 2400mm Basic laundry with cupboards for linen and cleaning items. Doors are 820mm wide. Laundry trough in bench. |
Although these 2 floor plan layouts of the laundry are workable, I would recommend a wider width if possible to allow for more room for storage under cupboards and work top space. I have allowed 650mm wide space for a washing machine, most machines are around 600mm wide, but it's good to leave some space for moving them for maintenance and just in case you have a really old machine that might be bigger. With that in mind, it is always a good idea to measure or get specifications of any appliance you intend to install to allow appropriate space to accomodate it.
DOOR SIZES:
In terms of door sizes to the bathroom, I personally always try and stay with an 820mm wide door. Going bigger is always fine, but less, I really wouldn't recommend. This is to allow for appliance installation and laundry baskets, trolleys etc.
LIGHTING:
Sanitary compartments are required to be fitted with artificial lighting if natural lighting as per Part 3.8.4.2 is not met.
Bedroom
Bedrooms today are usually equipped with a built in robe. Most houses also designate a bedroom as the Master bedroom. A master bedroom either has a built in robe or a walk in robe, and now commonly incorporate an ensuite.
I have worked on many projects where architects have created dysfunctional bedrooms due to there less than adequate room dimenions. I am going to suggest some bare minimum sizes you can incorporate into your design.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| 3000mm wide | 3600mm long (600mm of the room is used for the built in robe so actual usuable floor space is 3000mm) | Minimum Required 2.4m. |
 3000mm x 3600mm Very basic bedroom layout which allows for a built in robe and space for a queens sized bed and 2 side tables. I wouldn't recommend anything smaller than this. |
DOOR SIZES:
In terms of door sizes to the bedroom, I personally always try and stay with an 820mm wide door. Going bigger is always fine, but less I really wouldn't recommend.
LIGHTING:
A Bedroom is required to have natural lighting (a window) as per the BCA Part 3.8.4.2
Study / Home Office
Many new homes incorporate an area or room to use as a study or home office. When designing one into your own home, you should really think about your needs. You may require a simple area that only needs a space for a computer and printer. You may however need space for files, photocopier, book shelves etc.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| 3000mm wide | 3600mm long (600mm of the room is used for the built in robe so actual usuable floor space is 3000mm) | Minimum Required 2.4m. |
 2400mm x 2700mm Basic small study / home office. Allows for a built in workbench, and enough room for a bookcase. |
 2700mm x 2700mm Medium sized study / home office. Allows for a built in work bench and built in cupboards. |
Both of theses examples are as small as I would usually design for a study / home office. You could always go smaller in all you wanted was a study nook without a door into a room. In both these cases, the dashed line above the workbench denotes overhead shelfs. The workbench shown is 600mm wide but I would recommend 700mm wide.
DOOR SIZES:
In terms of door sizes to the study / home office, I personally always try and stay with an 820mm wide door. Going bigger is always fine, but less I really wouldn't recommend.
LIGHTING:
A study / home office is required to have natural lighting (a window) as per the BCA Part 3.8.4.2
Living / Lounge Room
This space is where people tend to spend a lot of time watching tv. When designing a house, think about the types of furniture you would include in this space and what the dimensions of that furniture would be.
It's hard to give exact dimensions of this space due to types and sizes of furniture, but also as modern homes tend to incorporate these areas into open living spaces, where one area intersects with another.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| 3300mm wide | 4200mm long | Minimum Required 2.4m. |
 4200mm x 3300mm Very small living space in my opinion. You could make it work, but I think it would make the space cramped in a space with enclosed walls. |
 4200mm x 3900mm Quite a basic space allowing for one 3 seater couch and one 2 seater couch. Slightly more spacious than the previous layout allowing for more leg space between couches and table. |
These 2 layouts are very basic but should give you an overall idea of what can be achieved in a room with these dimensions.
DOOR SIZES:
In terms of door sizes to the study / home office, I personally always try and stay with an 820mm wide door. Going bigger is always fine, but less I really wouldn't recommend as you will need plenty of room to move in furniture, especially couches.
LIGHTING:
A living / lounge room are required to have natural lighting (a window) as per the BCA Part 3.8.4.2
Kitchen
All houses are required to have a kitchen. There are many different styles and configurations for a kitchen, so working out what you will require in the design is a good start to determining the dimensions.
In modern homes, kitchens are usually open plan and not tucked away in a room with 4 walls.
| ROOM DIMENSIONS: | ||
| Width | Length | Ceiling Height |
| 3300mm wide | 4200mm long | Minimum Required 2.1m. Recommended 2.4m |
 2400mm x 3000mm Very small kitchen with an island bench. Oven under cooktop, overhead cupboards. Note that there is very little cupboard space for both dinnerware, glasses etc and food storage in this layout. |
 2400mm x 3900mm Similar to the previous layout except there is now room for a dedicated pantry. The pantry could also house the microwave. |
These 2 layouts are very basic kitchen layouts. The first layout is very small not allowing a lot of storage space. If designing for yourself, it is a good idea to work out exactly what is required, and get the exact dimensions of any appliances to be installed. You should also consider any appliances that will sit on the bech top permanently, as these appliances limit the workspace for preparing food.
Stairs
Many houses are 2 storey, or in some cases, more. In these houses stairs are the dominant feature in accessing different levels of the building.
| ROOM DIMENSIONS: | ||
| Width | Length | Head Height |
| 1050mm wide | to suit | Minimum Required 2.1m. Recommended 2.3m |
 L-Shaped Stair Min.1100mm wide |
 U-Shaped Stair Min.1050mm wide |
The 2 layouts I have shown are what I would recommend as the absolute minimum dimensions to use for these shaped stair cases, but I usually dimension all my stairs at 1200mm wide. In terms of stairs, more is always better. I say this as when moving furniture up and down the stairs, it can be quite difficult to get some pieces to the desired level of the house due to stairs being too narrow. Mattresses are a big item that can often be troublesome to get up stairs, especially king sized matresses.
Also note that the dimensions I have given are what I would recommend as an overall dimension (wall finish to wall finish). If you dimension a stair as 1100mm wide from stud work to stud work, the stair will be narrower due to wall finish thickness (usually 10mm plasterboard) and also any skirtings you may have.
Keep that in mind.
In addition to the information I provide for designing and drafting your own house, I have another side project that tells you how long a house or land has been For Sale or Rent in Australia.
It is also Free to Use and also has a search to give you a price range indication of house and land
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It is called Get House Date www.gethousedate.com.au Mobile Friendly too.