Designing Bathrooms: A Quick Guide for Architects

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A thoughtfully designed bathroom not only enhances the overall aesthetics but also improves its functionality and user experience. In this quick guide, we will explore the key principles and considerations architects should keep in mind when designing bathrooms that are not only visually stunning but also highly practical and efficient.

Among the essential areas of any building, the bathroom holds a unique place as it directly impacts the daily lives and comfort of its users. So, let’s dive into some of the main considerations Architects should look into when designing their next bathroom project:


Understanding User Needs

When designing a bathroom, you’ll need to understand the specific needs and preferences of the intended users. Consider factors such as the number of occupants, their age groups, mobility requirements, and any unique considerations they might have. This user-centric approach will ensure that the bathroom design caters to the people who will be using it most. After understanding the needs, you’ll need to ask practical questions like what is the budget that the customer has in mind, as this will affect the list of requirements that can be achieved within that.

Complying with Building Codes

When designing a wet area, these should be designed to be accessible, safe, and convenient for its users – at the same time, ensuring it complies with the NZ Building Code requirements.

Adherence to Building Code clause E3 Internal Moisture is essential to ensure that wet areas meet all the necessary requirements, keeping building users safe and protecting the integrity of the structure and finishes by preventing water damage. We recommend following E3/AS2 as this is the best practice and provides more detail.

Health and Safety

One of the primary concerns in wet areas is the risk of slips and falls, particularly for older individuals. To mitigate this risk, we recommend the floor or the floor finish in the bathrooms to have a Slip Resistance Value (SRV) of 39 or a coefficient of friction of 0.4 in, as per AS 4586-2013. For more information, refer to table 2 of D1/AS1 which details flooring materials and finishes to be used with acceptable slip resistance. If installing an acrylic shower tray, look for trays that have non-slip features, like our Newline Acrylic Shower Trays. 

Other design considerations might include, avoiding sharp edges in the bathroom design, installing grab rails in and beside the shower cubicle, as well as specifying shower enclosures that comply with grade A safety glass in framed and unframed shower doors in accordance with NZS 4223.3: 2016 Glazing in Buildings – Part 3: Human impact safety requirements.

Space Planning

Efficient space planning is always important, for a bathroom then… it is crucial! Carefully consider the layout and placement of fixtures to maximize available space. Avoid cramped and cluttered arrangements, as they can lead to an uncomfortable user experience. Explore various layouts, such as single-wall, galley, or ensuite configurations, to find the most suitable arrangement for the project. Consider the space required your shower, vanity and furniture door opening, as well as the space available around your toilet seat.

Access and Circulation

Accessibility and circulation within the bathroom are essential for a seamless experience. Ensure that there is enough space for easy movement, especially in public or commercial bathrooms that may have multiple users simultaneously. For larger bathrooms, consider incorporating zones for specific functions, such as bathing, grooming, and dressing, to improve user flow.

When designing a bathroom for wheelchair and ambulant users, consider some of the following factors:

  • Providing level access for easy access. (e.g., recessed trays, instead of hobbed ones).
  • Installing hand-held shower heads
  • Installing grab rails for improved mobility of the user
  • If installing a shower seat, ensure to locate on the wall adjacent to the shower head for easy access of the user.
  • Allowing leg space underneath sink/vanity.

For further information, check section 10 of the NZS 4121:2001 Design for access and mobility: Buildings and Associated Facilities, which sets out design requirements for accessible bathrooms. 

Natural Light and Ventilation

Where possible, harness natural light to create a bright and inviting bathroom environment. Strategically place windows and skylights to provide ample illumination during the day while ensuring privacy is maintained. Adequate ventilation is equally crucial to prevent moisture buildup and maintain a healthy indoor environment.

Material Selection

Whenever possible, choose durable and high-quality materials for your next bathroom project. That is especially important, when it comes to the shower area, as you’d want to make sure you’ve got a reliable shower enclosure, or a tile over tray that can successfully contain water, avoiding any leaks or water damages.  The list of materials to be considered in a shower is quite extensive, and so we have highlighted some of the most important below:

Shower Enclosures

After deciding on the user requirements, space planning, access, and circulation, you’ll have to decide whether you’ll use a tile or acrylic shower in this project. You can read our blog on ‘Acrylic vs Tiled Showers: Which is Best?” for some extra guidance.

As for acrylic showers there are several shapes of shower enclosures such as 2-sided, 3-sided, neo and curved. So, for example, if you are designing a small bathroom, you may suggest a curved or neo shower enclosure to your customer, as this are space-saving options, that help maximize the floor area of a small bathroom. 

To make things as easy as possible, we have put together a Buying Guide on How to Buy a Shower Enclosure – which can guide you step by step to decide on the best shower enclosure for your project. When choosing the shower enclosure configuration, remember to coordinate the shower size with its adjacent fixtures like toilets or sink countertops.


The importance of convenient control placement and the possibility of multiple control options. There are several options like wall-mounted showerheads, ceiling-mounted rain heads, to the practical hand-held shower hands.

Tile Over Trays

If going for a tile shower, we recommend the use of tile-over trays, which offer the appeal of a tile shower and the peace of mind of an acrylic shower system.

Here at Newline Showers, we offer options such as the ProFinish™ Tile Tray System, which replaces the need for a traditional sand and cement formed tile shower base. ProFinish is a tile over tray system that is made of high-density rigid polyurethane, and is available in standard sizes, and can also be customised to suit individual requirements to suit channel or point drains in virtually any position.  These trays can be hobbed or recessed and are suitable for all types of flooring including solid timber flooring, particle board, concrete, or tile subfloors.

ProFinish™ Tile Tray System

DryFit™ Tiled Shower System

Another option is the Newline DryFit™ Tiled Shower System, which does not require a traditional waterproof membrane, as the single sheet acrylic liner is the waterproof membrane.  These can also be installed recessed or with a hob and have been endorsed by noteworthy Architects due to its unique ability to fully contain water. 

If you want more in-depth knowledge on tile over trays systems, we recommend you have a read at our blog titled ‘What are the types of tile shower trays?’


Incorporating niches or storage solutions while considering water exposure.

Door Location

Addressing door size, accessibility, and the choice between a curb or curbless design.

Wet Area Wall Structure

The walls in wet areas can be constructed using different materials, such as concrete, timber or steel frames, which with their own requirements. For timber and steel materials:

  • Sufficient depth to accommodate plumbing services like pipes.
  • Provision of dwangs and support for fixtures such as wall-mounted WC, cabinets, built-in cisterns, grab rails, and plumbing outlets.
  • External walls should be insulated to maintain temperature and reduce energy loss.
  • Adequate treatment to protect against the risk of water damage.
  • Sufficient rigidity to support the chosen wall finish.

It is important to note that framed walls do not offer good sound insulation, so careful consideration and specification of wall linings are necessary to minimize sound transmission from bathrooms to other parts of the building. In the case of steel frames on exterior walls, a thermal break is required to prevent heat transfer.  When opting for concrete walls in wet areas, certain guidelines must should be followed, including:

  • Providing a waterproof finish to prevent moisture absorption in the case of concrete masonry and plastered finishes. This may involve using a paint finish in accordance with E3/AS1. A steel-troweled concrete surface finish is considered impervious, similar to floors.
  • Exterior walls must meet the requirements outlined in E3/AS1 and H1.
  • Plumbing and electrical services should be pre-installed in concrete walls, as retrofitting them can be challenging.

The choice of wet area wall material, whether timber, steel, concrete comes with specific considerations to ensure functionality and durability.  Meeting the outlined requirements for each material will help create reliable and well-performing wet areas in residential and commercial buildings.

Plumbing Considerations

Work closely with the plumbing team to ensure proper placement of pipes and drains. Plumbing fixtures must be located strategically to facilitate efficient water flow and drainage. Here are some of the most common issues within bathroom plumbing:

Incorrect Pipe Sizing

Using pipes that are too small can cause reduced water pressure and flow, while oversized pipes can lead to water hammer and increased energy usage.

Faulty Pipe Joints and Connections

Leaky or improperly sealed pipe joints can result in water wastage, water damage, and increased utility bills.

Improper Drainage

Incorrectly installed or poorly designed drainage systems may cause blockages, slow draining, or water pooling issues.

Using the Wrong Pipe Material

Selecting the wrong type of pipe material for specific applications can lead to premature deterioration and possible contamination of water supply.


While this blog post only scratches the surface of bathroom design, it highlights the complexity and variety of considerations involved.

Designing bathrooms as architects requires a delicate balance of aesthetics, functionality, and user experience. By understanding user needs, planning efficient layouts, incorporating natural light, and choosing suitable materials, architects can create bathrooms that elevate the overall design of a building while enhancing the comfort and well-being of its occupants.

Additionally, prioritizing safety, sustainability, and smart technology integration will ensure that your bathroom designs remain relevant and forward-thinking in the ever-evolving field of architecture. So, let your creativity flow, and design bathrooms that leave a lasting impression!

Give us a call on 0508 639 5463 or email us at [email protected] to see how our products can help you in your next bathroom project!

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