How To Design A Bathroom | Complete Step-By-Step Guide

Is it time to invest in your home by completely renovating your bathroom? Are you starting from scratch with a new build or extension and looking for some advice on how to design a bathroom? This is the post for you!

It’s one of the busiest and hardworking rooms in the house with systems that not only must look good but function tirelessly to keep your family clean and healthy. And, alongside the kitchen, it’s one of the rooms that can add the most value to your property.

Where do you start on this project? This ‘How to Design a Bathroom Guide‘ gives you all the tips needed to organise your thoughts and prepare a realistic and functional plan.

I’ve broken it down into five main sections (with subsections within them) to help make the whole process a little more manageable to work through. These are; Budget, Research, Design, Ordering and Installation.

So, grab a pen and paper to make some notes, or simply bookmark this page to come back to.

Let’s get into it!

How To Design A Bathroom: Complete Step-By-Step Guide

1. How Much Is In Your Bathroom Budget?

While every home has a bathroom, they are not all built to the same standard. On average, your simple bathroom renovation can cost as little as £2,500 all the way up to £7,000 or more, according to TradesmenCosts. The wide range is due to a huge array of choices available for fittings, finishes, and ultimately square meters. Where does all the money go? Let’s break it out.

  • Bathtub: £100 to £500
  • Basin: £50 to £200
  • Vanity: £100 to £300
  • Shower enclosure: £100 to £600
  • Floor tiles: £50 to £70/m2
  • Plumbing: £1000 and up
  • Electrical fixtures: £100 and up

Of course, anytime that you are selecting a custom or premium finish, there is almost no limit to how much you could spend. The cost of a fixture does not pay for the labour required for installation.

Once you have finalised your budget, small or extravagant, remember that you need to add about 10% for a contingency. This allows you to prepare for hidden problems when you pull up the old floor or knock a hole in a wall. If your contingency remains after the project is done, treat yourself out for a night on the town. 

Setting aside a budget from the beginning can help you stay on schedule and avoid getting lost at the home improvement store while drooling over a marble tub that is simply not attainable. It can also help when interviewing a contractor to determine if they are priced out of your range.

2. Researching Your Wants And Needs To Design A New Bathroom

Part of designing a bathroom should always include taking the time to determine how you want your bathroom to be used. Is this your private oasis set aside just for you and your spouse? Are you installing a guest en suite with top of the line sanitaryware? Maybe this is the bathroom that the kids run in and out of all day long.

Work your way down the list of amenities that you need in the room and then add on a few items that you want.

Bathroom Items List

  • Bath and/or Shower: A quick rehab can replace your combination shower tub in just a day or two. You can change things up with a footed freestanding tub, a walk-in shower with glass or tile enclosure, or a deep spa tub with jets. 
  • Basin: Is there room for a full console or is the space large enough just for a pedestal sink? Do you need twin basins? Will it be mounted in a vanity? Treat yourself to a modern vessel style.
  • Toilet: Explore the variety available to match your space, design, and physical size. Opt for a hidden or exposed cistern, high level, wall-mounted, or the traditional close coupled version.
  • Storage: Is there room for a built-in closet? You can add shelves over the toilet, opt for a mirrored cabinet, or plan on standalone shelving for your towels and toiletries.
  • Heating: Does the room require a new heat source? You can supplement the old radiator with a heated towel rail, some underfloor radiant heating, or a heat lamp. A new radiator cover can add storage while dressing up the room.
  • Flooring: Vinyl flooring still delivers the best investment and can be found in a huge array of colours and patterns. Upgrade to tile, natural stone, or laminate if you desire a more durable and upscale appearance.
  • Walls: A drop-in tub or shower enclosure saves money and time. Personalize the result with marble tiles, mosaics, or a sparkling backsplash featuring coloured glass. Don’t forget to pick complementary paint for the walls.

Accessible For Kids, Seniors And You

If you are building for the extended family, and that includes somebody in a wheelchair, your design will require wider doors, extra floor space, roll-up counters, and an oversized shower enclosure.

Perhaps you stand well over six feet tall. Your showerhead will need to be positioned higher and you may want a higher toilet. Are you always fighting over the basin in the morning? A double-vanity could help reduce stress.

Find Inspiration

If all you can picture in your mind for a new bathroom design is the old fashioned three-piece, it might be a good idea to spend some time diving into the internet to see what styles and features are trending. Pinterest, Instagram, and home design websites are overflowing with images and tips.

Start building your own project board with samples of fixtures, finished spaces, and materials that grab your attention for quick reference when it comes time to start ordering supplies.

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3. Design Is In The Details

Now that you know how much you want to spend and what type of finishes you want to include, it is time to finally start designing a bathroom.

Are you tackling this job as a DIY project broken up over a few weekends, creating the design yourself and hiring out the labour, or calling up a home improvement contractor? This decision will make the largest impact on the cost.

If you are opting for the hands-off approach, expect to pay an additional 20% or more over just hiring a tradesman to follow your directions. Are you still not sure because you want to compare some hard numbers? Many bathroom renovation companies will come to your home, measure the space, and provide a free estimate.

Design a Bathroom floor plan

Do-It-Yourself Starting Point

You will need to create a measured floor plan for the proposed bathroom design. Measure every space in the room including walls, floor, windows and doors. Is there a boiler or radiator that will be staying? Mark where the current fixtures are plumbed. Also, take note of current lights, wall switches, and power outlets.

Sketch a Floor Plan

Use a free online room design tool like RoomSketcher or Planner5D to create a blank floor plan. You can always go old school with the pen and paper–just remember to run off a few copies so you can make mistakes. Now you can create the bathroom of your dreams by placing everything where you would like.

ProTip: Moving plumbing and lighting fixtures will add to your cost and construction time.

Spend some time thinking about the layout. Can you sit on the toilet without bumping your knees on the vanity? Is there room in the standing shower to turn around? Will you be able to reach the towels stored over the traditional high-mounted cistern? Will the door open without bumping into something else? Is there really enough space for a closet?

Consider the average size for typical fixtures when positioning items in your floor plan.

  • Bathtub combo: 1700mm X 700mm
  • Freestanding tub: 1800mm X 800mm or more
  • Toilet: 40cm X 70cm
  • Vanity sink: 550mm to 800mm wide and 400mmto 500mm deep.
  • Shower enclosure, square: 700mm to 1500mm

All these measurements are for the most popular pieces sold on the market. You can find smaller versions designed to tuck into a tight powder room or larger when you have the building space for a jetted tub for two.

While drawing up your floor plan, give yourself a little room beyond expectations to allow for variances in the size of the final sanitaryware that you purchase for the project. If your bathroom is small, make sure to double-check the dimensions of every unit before you place your order, especially on custom pieces that may not be returnable.


Have you always wished for a little more light when taking a shower? Is the overhead light too bright? Is your linen closet always dark? Now is your best opportunity to update or add lighting fixtures. Think about vanity lighting, a waterproof fixture for the shower, and even under-cabinet LED strips that provide a built-in nightlight.


Was your home built before ground-fault interrupt outlets (shaver sockets) were part of the design? Add one by the sink and along the wall so that charging up the razor or electric toothbrush is no longer a chore. If you have an older home, now is a great time to replaced old wiring while you have access behind the walls.

Extractor Fan

Another upgrade that is needed for older homes is adding an extractor fan. You will need room in the ceiling or along a wall to run the hose and allow it to blow damp air directly outside. Some fans are built as part of overhead lighting while others can be installed as a standalone unit. Do you love tech toys? Smart exhaust fans can be controlled by an app on your phone.

Now that you have all the permanent fixtures for your design added to your finalised floor plan, it is time to start sourcing materials and muscle.

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4. Order In The Goods

First off…don’t go ripping out the walls in your bathroom, yet! Put off your demolition day until you have finished finding all the materials and tradespeople needed to complete the job. Living without a door on the WC is not fun!

If you have a basement or garage, you can start picking up the materials and finishes when you find them. However, if you live in a flat or semi-detached home with little functional storage, you will need to time the delivery of supplies to coordinate with the different stages of construction. If you hire a renovation company to tackle the entire job, they will be responsible for timing the deliveries and storage, but that could still include using your lounge for a few weeks.

When purchasing custom products such as cabinetry or special order faucets and vessel sinks, you may need to allow up to 10 weeks for the item to arrive. Before walking down the aisle at the bathroom design centre and mentally selecting everything that you love, speak to a sales rep that knows what is typically in stock and what requires some lead time.

ProTip: Did you know that winter is the best season for shopping for bathroom fixture bargains?

Most contractors are busiest in the warmer months of the year as homeowners don’t mind the open windows needed for fresh air and ventilation. This means that overstocked finishes will drop in price after the holidays. Look for sales and save big or splurge on that travertine floor tile!

Create a timeline schedule as part of your bathroom renovation file that shows each stage of the project, when supplies are scheduled to arrive, and the approximate time needed for installation before moving onto the next segment.

5. Building Work And Installation Of The Bathroom Fixtures: What To Expect

Finally, you have to consider what kind of structural building work may be required. If the room was not originally a bathroom, you may need planning permission to start the job. Once you remove the old fixtures and rip out the walls, will you need to replace wood, brick, or floors?

Bathroom Installation

Types Of Potential Building Work

  • Structural reinforcement of walls, windows, and doorways
  • Replace subflooring
  • Update old electrical wiring and sockets
  • Move pipes to support the new location of plumbing fixtures
  • Add insulation to exterior walls
  • Plaster new walls and ceiling
  • Install a new window
  • Paint

Any unexpected building work that was not part of your original plan and budget can easily add two weeks to a month to your project. It may require a visit from your local building inspector to ensure that your home is structurally sound. It is wise to mentally create a contingency to your planned timeline so that you can manage the stress of added expenses.

How Long Does A Bathroom Renovation Take?

On average, a professional bathroom renovation will take 2-3 weeks. However, it can take up to six weeks or more depending on how much work is involved and how complicated the project is. Equally, it’s possible to trim that down to three-five days if you only switch out the sanitaryware without having to move pipes or do any major tiling or building work.

Can you do it in three days? Not likely. For most DIY projects, take the professional projected hours and multiply that by three. If you are hiring all the trades yourself, the different parts of the project may be finished quickly, but you may have a day or two until the next trade is available to tackle their part of the job.

The typical timeline of events for the building phase are:

  1. Demolition – Knocking down any walls and ripping out the old bathroom etc.
  2. Structural changes – Any new walls, windows, doors and interior stud work.
  3. First fix – Adding/moving electrics, plumbing, gas etc. Getting the cables and pipes in the right place for your new layout.
  4. Plastering / preliminary decorating – Getting the room plastered and the first few coats of paint on as a base layer. Tiling or fitting waterproof boards in certain areas may also take place.
  5. Install fitted bathroom furniture – Bath in place, shower tray/cubicle, toilet, sink etc…
  6. Floor and wall finishes – Finish tiling or installing waterproof boards around furniture, finish decorating the room.

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Who’s Installing The New Bathroom?

Which way should you go? Let’s look at a few pros and cons of holding the hammer yourself, hiring all the tradespeople yourself to do the work, or signing up with a specialist bathroom company.



  • Least Expensive
  • Pride of caring for your home
  • Work at your own pace–you set the schedule for shutting down the most important room in the house.
  • Selecting all the finishes personally
  • Improve your understanding of how all the systems in your house work.


  • May use more materials when you make mistakes
  • The finish may not look as good as a professional–cutting angles, applying silicone caulking, and grout take experience for a polished look.
  • Frustration of the DIY learning curve–nobody does it right first, second, and sometimes third time.
  • Fixing surprise problems is all on you.
  • You are responsible for obtaining building permission and insurance if required.

Hire All The Trades Yourself


  • Professional finish to the project.
  • You get to pick the exact finishes that you want.
  • You remain informed and in control during the entire process.
  • Trades carry their own liability insurance if something goes terribly wrong.


  • You must take the time to check their licences and trade affiliations to make sure of their legitimacy.
  • The project will cost more than DIY
  • You are responsible for coordinating the schedule for various trades, which often slows down the building process.
  • The need to find yet another tradesperson when unexpected problems are exposed after demolition.
  • You are responsible for obtaining building permission if required.

Hire Specialist Bathroom Company


  • Professional finish that often comes with a builders warranty.
  • Fastest installation.
  • They have all needed tradespeople as part of their service saving time and frustration.
  • They handle all required insurance, licences, and permissions.


  • The selection of finishes and materials may be limited to their catalogue.
  • Limited room for adjusting schedules for your convenience.
  • Price rises significantly over the other methods–you pay for convenience.

Are You Ready To Design Your New Bathroom?

Now you have all the tools needed to begin your bathroom design and renovation project. Whether you do it all yourself, team up with your trades, or bring in a professional company, you can use this as a quick reference when you are ready for each step of the process.

There will be ups and downs, stress and mess but it will all be worth it in the end. I wish you all the best in designing and renovating your new bathroom. Good Luck!


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.