Bathroom design can be a great way to improve your home’s look and functionality. However, it takes some planning and thought to do it right. Fortunately, many rules, regulations, standards and guidelines can help you successfully plan and execute a bathroom construction project.
This article covers bathroom design basics, including layout, waterproofing, electrical and lighting requirements, ventilation, and floor waste. We will also discuss why getting a licensed and registered professional is crucial when completing a bathroom project.
Planning a bathroom layout can be an exciting and vital step to the success of your project. It’s essential to ensure the dimensions of your bathroom layout meet Australian standards. This is because the size of a bathroom can affect accessibility, aesthetics and hygiene. There are many guidelines for each particular area of the bathroom, including:
These measurements are applicable for both small and average bathrooms.
When planning a layout for a small bathroom, it’s essential to ensure that your bathroom meets minimum requirements. The minimum bathroom, ensuite and wetroom size in Australia is 1400mm by 950mm for a rectangular floor plan and 1200mm by 1200mm for a square floor plan. These bathrooms only include a toilet and sink, meaning they won’t be practical, fully functioning bathrooms.
It’s also important to remember that size allowances vary by state. However, when working with a registered builder, they will have access to the latest guideline documentation for reference.
For a fully-functioning bathroom with a toilet, vanity, cabinetry and shower, the minimum size is 3000mm by 2000mm. Typical Australian households usually choose a slightly larger floor plan, measuring 3500mm by 2500mm. A more expansive bathroom may even be up to 4000mm by 5000mm in size.
The Building Code of Australia is a document that sets out the requirements for the design, construction and performance of building work. This code, in conjunction with the National Construction Code, outlines expectations and Australian standards for all registered builders and contractors in Australia.
Hiring a registered builder for your bathroom project is required for various areas of construction state by state. This will allow for a smoother and more successful project. At TIC Bathrooms we only work on projects within the Canberra, ACT and surrounding NSW areas, however, we will also detail out requirements for other states as well.
Australian Capital Territory
If undergoing any building or renovation work valued at more than $5000, you are required to hire a licensed building practitioner.
You must hire a builder with a class A, B, or C licence. The builder must hold a class D licence if there is no structural work. Your tiler may carry a class D licence; however, plumbers and electricians must have the appropriate licensing.
Finally, whilst a waterproofing licence is not required in the ACT, your waterproofer must issue a compliance certificate following the waterproofing installation.
New South Wales
In NSW, a builder’s licence is required for any work exceeding $1000, including materials and labour. For all bathroom renovations, you must hire a licensed bathroom builder. Additionally, all waterproofing must be done by a licensed waterproofer.
In Victoria, a registered building practitioner must complete all work valued at $5000 or more. Additionally, all bathroom renovations must be completed by building practitioners with either a Domestic Builder: Unlimited or Domestic Builder: Limited registration. A builder with a limited registration will require a DBL-L registration to carry out any bathroom, kitchen or laundry renovations.
Whilst you do not require a waterproofing specialist in Victoria, you must make sure your waterproofing conforms to the AS 3740.
Any building work exceeding the cost of $3300 must be completed by an individual with a valid builder’s licence. Additionally, bathroom renovation specialists require a restricted licence. This licence does not include plumbing or electrical work; however, holders can subcontract.
Additionally, all waterproofing work will require a waterproofing licence.
Licensed building contractors must complete all building work. Building contractors are also required to hold a building supervisor license. Additional licensing for bathroom renovations include “scope of work” licenses, which authorise builders to carry out “alterations and renovations”.
Additionally, all plumbing and electrical work must be completed by licensed specialists. Upon completion, the bathroom renovation specialist should provide a compliance certificate for waterproofing.
A builder’s licence is required for work exceeding $20,000. When you are hiring a contractor in WA, make sure they’re registered with a trade association and have a strong portfolio.
A waterproofing licence is not required; however, you should expect a compliance certificate upon the work’s completion.
Registered building practitioners must carry out bathroom renovations with a “builder: low rise” accreditation. This accreditation does not authorise the practitioner to complete plumbing or electrical work; however, they can subcontract specialists for the job.
Renovation work in NT does not require a licensed builder unless the job includes an increase in floor space or costs an excess of $12,000 for labour and materials.
Tilers also do not require licensing in NT; however, trade association-affiliated tilers are preferable to ensure the work is of high quality.
The Building Code of Australia and the National Construction Code standards will ensure your project is successful, durable, and high quality. Below we take a closer look at some of the standards Australian builders and contractors are expected to follow.
Referenced in volumes one and two of the National Construction Code, the AS 3740 refers to current Australian Waterproofing Standards. These standards are the same across all states and specify that waterproofing in a bathroom must:
To better understand why these standards are so important, let’s learn more about waterproofing.
Waterproofing protects your building from water damage and moisture by creating a water-resistant barrier. This process is completed by using a waterproof system.
Waterproofing systems include various methods such as liquid membrane, sheet, or spray application. The waterproofing system used will often depend on the situation. At TIC Bathrooms, we typically opt to use a liquid waterproof membrane. A waterproof membrane is a layer of water-tight material.
Some states allow unlicensed waterproofing, but it is best not to attempt it yourself. Poor waterproofing can affect the safety and lifespan of your bathroom. It is also among Australia’s top three building defects and can cause issues such as:
In addition to waterproofing your bathroom, another thing required by the AS 3740 is the installation of flashing. Flashing is a stainless steel barrier installed to prevent water from seeping into undesired areas. Vertical corner flashing is required for shower or bath shower combo areas up to 1800mm above the floor level or base of the bath. This may only be installed externally where external waterproofing membranes have been used. Flashing is also used at the floor-to-wall junction and doorways and can be installed either externally or internally.
If you’re interested in learning more about our waterproofing process, check out our dedicated process page here. Quality waterproofing is only one part of the project. It is important to account for water in all areas of your bathroom, especially when it comes to electrical safety.
In addition to 3740, the National Construction Code also references the AS 3000, which outlines all electrical regulations when completing bathroom installations. Section 6 of this standard outlines electrical regulations when installing in wet areas or areas with damp situations. These regulations ensure that water does not come into contact with any electrical outlets or appliances.
The AS 3000 firstly divides the bathroom into four zones. These zones are:
These zones are then used to determine the placement of many different things, including sockets, switches and lighting. Some zones will require special sockets and outlets. This includes Ingress Protection (IP) rated switches and lights as well as sockets fitted with residual current detectors (RCD).
An IP rating is a rating that shows how well a device can withstand things like user intrusions (hands, fingers, etc), dust, dirt, and moisture. For example, IPX4 would read as follows:
The IPX4 is the most commonly required rating when considering electrical placements. Below is a general outline of how each zone differs regarding IP and electrical requirements:
In Australia, all electrical work must be carried out by a licensed electrician. They will provide you with a safety certificate when the work is finished. Safe and properly tested electrical work is essential in wet areas. If you’d like to learn more about our electrical rough-in and fit-out processes, take a look at our full process documentation. Another important inclusion when considering moisture build-up is ventilation.
If you enjoy a steamy shower now and then, you’ll know how important good ventilation is. Luckily, the Building Code of Australia outlines all the essentials for proper bathroom ventilation, including minimum bathroom window size requirements and exhaust fan specifications.
The bathroom must have an openable window the size of at least 5% of the floor space for ventilation purposes. You may also opt for an exhaust fan if this is not achievable. The exhaust fan must provide an exhaust rate of at minimum 25L/s airflow; however, it is typically recommended this is increased to 50L/s to 100L/s for bathrooms with a shower to reduce condensation.
Poor ventilation and excess condensation can result in numerous issues, such as:
On top of adequate exhaust rates, you’ll also need to install an exhaust fan with a suitable noise rating. Typically a noise rating of 1.0 or less is recommended.
Finally, you’ll need to consider the positioning of your exhaust fan. The best locations are over the sink, close to the shower or between the shower/bathtub and toilet area; however, this can vary depending on the size of the bathroom. A more central exhaust fan can provide adequate ventilation for smaller bathrooms, whereas large spaces require more careful consideration.
If your toilet is located in a separate room, both rooms will require ventilation.
Finally, and most often overlooked, is floor waste.
A floor waste is a type of drain that is installed in a graded floor. This ensures that all water will flow towards the drain and be drained away. In buildings such as apartments, motels and hostels, floor wastes are required by law. However, for houses, the rules are more open to interpretation.
This is primarily due to the difference between enclosed and unenclosed bathing spaces. When installing an enclosed shower, the water is typically contained within the area of the shower, meaning a floor waste is not necessary. Whereas unenclosed or shower/tub combo will require a floor waste due to water escaping the wet area. This is the minimum requirement, however, with some plumbers opting to add additional floor wastes to account for further water from things such as the basin.
There are three types of floor wastes, dry, trapped and gullies. A dry floor waste is a drain with a pipe that directly discharges to the outside or over a gully trap. A gully trap is essentially a wide open container that receives piped wastewater which is discharged when full. Gully traps typically have a vent to remove the potential of foul odours rising from drained wastewater. As dry traps do not have a water trap, they use hinged flaps to prevent pests and insects from travelling up the drain.
A trapped floor waste is identical to a dry floor waste except with the addition of a water trap. Water traps are pipes with a downward and then upwards curve, similar to the letter ‘U’. These traps work by creating a seal using water in the bend of the ‘U’ to prevent smells or other things from coming through your pipework.
Finally, we have the floor waste gully; a floor waste gully can be connected to and funnel wastewater from multiple fixtures. These fixtures are limited only by the number of discharge pipes and the total distance between the floor waste gully and the fixtures.
Installing a floor waste requires consideration towards ‘falls’. A fall refers to the floor grading in relation to the floor waste. Floor grading can depend on local authority interpretations, with some considering grading unnecessary where an additional voluntary floor waste or floor waste gully has been installed. As a rule, however, it is considered good practice to grade floors when installing a floor waste. The bathroom floor fall at minimum, should be 1:100 (10mm per 1m), including when an enclosed shower is installed. Where an unenclosed shower area is used, the fall should be a minimum of 1:80 (12.5mm per 1m). Any fall proposed at a greater flatness than a 1:100 ratio will need to be confirmed as effective before work is signed off.
Installing a bathroom to Australian standards requires extensive forward planning vetting of any builders you choose to employ. Accessing the most up-to-date Building Code of Australia documentation typically incurs some fees; however, if you talk to your builder or renovation specialist, you can typically discuss how they ensure your job is up to standard, as well as what certificates will be provided upon completion. Ensuring that your bathroom layout, waterproofing, electrical installation, ventilation and floor waste are all up to standard will future-proof your new bathroom and improve the value of your home in the long run.
If you’re interested in working with fully-licensed, registered and well-reviewed renovation specialists, get in touch with us today at TIC Bathrooms.