Skip to Content

A Complete Guide To Adding A Bathroom To An Old House

The ratio of bathrooms to bedrooms in any house can affect its functionality, especially for its occupants. And with most old houses not meeting the required ratio of two bathrooms to three bedrooms, adding a new bathroom to your home can make it more comfortable.

However, renovating an old house can be pretty challenging, thanks to its outdated features and designs, so after thorough research, we came up with this complete guide to adding a bathroom to an old house.

A bathroom, also referred to as a washroom, is a particular room in any home or residential building that features a toilet, a shower, and a bathtub. (1) And in most parts of the world, bathrooms also include washbasins and grooming space.

Over the last half a century, the number of bathrooms in the United States has doubled. (2) However, most old homes still have fewer bathrooms, so in this article, we will help you determine:

  • the cost of installing a new washroom
  • how to design your new bathroom
  • how to determine the exact location of the new bathroom
  • what you’ll need to consider when adding a new bathroom to a new house

This is a complete guide to what you need to know when it comes to adding a bathroom to an old house.

The Value of a New Bathroom to Your Old House

Even though you won’t recoup the whole amount spent on the project when selling the house, it does still increase your home’s value. But the price of creating a new space can be pretty high compared to adding to an existing space. And that is because you’ll spend more on partitioning a room.

Note: This post may contain affiliate links which will take you to online retailers that sell products and services. If you click on one and buy something, I may earn from qualifying purchases. See my Affiliate Disclosure for more details.

But like most costly renovations, installing a bathroom won’t return the entire investment when selling the house. And according to the National Association of Realtors, a bathroom can recoup approximately 60% of the installation cost when sold. Fortunately, prospective buyers value bathrooms greatly, and this can help you sell your home faster and at a better price. (3)

And if you plan on living in it for several years, then adding the extra bathroom can help make your old house more comfortable and increase privacy.  

Factors to Consider When Adding Another Bathroom to Your Old House

Before even getting started on the project, there are several factors you need to think about before embarking on the renovations. Here’s a breakdown of them…

The Cost of Installing a New Bathroom to an Old Home

Generally, the cost of adding an extra bathroom in your home can range from $5,000 to $35,000. But using an existing space can cost you about 60% less than creating a new space. (4) However, this price varies depending on the fixtures used and the exact location of the new bathroom in the house.

The cost of adding a new bathroom upstairs ranges from $8,000 to $35,000. But this price can be reduced by the presence of some plumbing lines upstairs. If you add a new bathroom in places with no plumbing, you’ll have to install new pipes.

Converting your laundry room to a new washroom can save you a few thousands of dollars because of the plumbing lines already installed there. If your old home has a huge closet, then you can convert it into a bathroom. And depending on the plumbing and size of your wardrobe, you can spend anywhere between $5,000 and $20,000.

Another option that can provide you more space is utilizing the garage. Installing a bathroom in your garage can cost you about $25,000. And the good thing about the garage is that you won’t need some luxurious finishes.

Here’s a further breakdown of the costs associated with each part of the bathroom…

  1. The Cost of a Bathtub

A bathtub is the centerpiece of most bathrooms, and if you’re looking to increase the cost of your home, then you should add one to your bathroom. Generally, the cost of tubs ranges between $200 and $8,500. The price of a new tub varies with the styles, size, and material used.

A jet/whirlpool tub comes in a wide range of sizes and shapes, and their average price is about $5,000. But if you are looking for a cheaper option, you should go for soaking or clawfoot tubs. The average price of a clawfoot tub is about $2,000, while the soaking tub is approximately $1,000. (5)

The average price of walk-in tubs is $5,000, but this varies with the features added. A walk-in tub is ideal for people who have a hard time using standard tubs. Plus, they include all the main features of high-end tubs like built-in alcoves and whirlpool jets.

If you have a bigger space, you should add a freestanding tub whose price ranges between $750 and $12,000.   

  1. Showers

The average cost of adding a new shower in your new bathroom is about $5,262. And this will vary depending on the size, material, and style. The cost of installing a 32 in. sq. customized tile stall is between $4,200 and $8,500, while an acrylic stall will cost between $750 and $3,000.

Installing a 32-inch square model walk-in shower will cost you between $4,200 and $8,500. If you have a small space, then you can opt for a tub-shower combo. (6)

Luckily, numerous showerheads in the market can fit perfectly in your bathroom, including handheld showerheads and fixed showerheads. But if you’re looking for energy and water-saving showerheads, you should go for the ones with a WaterSense label. (7)

  1. Toilet

The average cost of installing a toilet in your new bathroom will range between $224 and $531. But this price will vary depending on the type of toilet you purchase, with the cheapest option going for as low as $350. (8) Some of the most common types of toilets that you can add to your home include:

  • Dual-Flush Toilet: Dual-flush toilets use both a handle and two buttons to flush. This type of toilet uses less water to flush liquid waste and more for solid ones. (9) The price of a dual-flush toilet ranges between $200 and $500.
  • Low-Flush Toilet: This toilet is designed to use less water than the high-flush options. There are two types of low-flush toilets (single-flush and dual-flush toilets). (10) The price of a low-flush toilet ranges between $380 and $620.
  • Upflush Toilet: Instead of using gravity when flushing waste, this type of toilet uses a heavy-duty pump to force the debris through the drain. A switch and float usually activate this pump. And when the lower part of the tank fills up, the pump moves the waste down the drain. (11) The cost of an upflush toilet ranges between $600 and $1,300.
  • Wall-Mounted Toilet: A wall-mounted toilet is a unique space-saving and sleek toilet that you can install it the right height. And the fact that its tank is hidden in the wall makes the room relatively easy to clean. (12) The cost of a wall-mounted toilet ranges between $150 and $1,200.
  1. Bathroom Sink

A bathroom is incomplete without a reliable sink, so make sure you pick the best option that matches your interior design. Installing the sink will cost you between $40 and $300, but the cost can go even higher in some cases. The price of the sinks will vary with the design, size, and material used to make them, with porcelain sinks being the cheapest option available. (13)

  1. Bathroom Faucets

A great and reliable faucet should do more than prevent water leakages and pour water; it should also enhance your bathroom’s interior décor. Luckily, these faucets have a wide range of handles for cold and hot water, like crosses, levers, and knobs. (14) Make sure you pick a high-quality faucet that will serve you for a very long time.

So you should be ready to spend between $73 and $160 for a new faucet. (15)

Where Can You Add a New Bathroom in Your Old House?

Generally, you can add a bathroom anywhere with more than enough space in your home. However, the decision will depend on your electrical and plumbing setup. Another factor that can help you pick the right place for your bathroom is your washroom style; for example, en-suites should connect to the master bedroom.

Therefore, the first thing to consider when selecting the space for your bathroom is the plumbing setup. After all, installing some new plumbing lines can be pretty costly. Some of the most common areas for bathrooms in most houses include:

  1. Closet

If you don’t have enough space for a new bathroom in your home, then you should try the closet; after all, most old houses have walk-in closets. A closet with about 25 sq. ft. can fit a half bath, including a toilet, sink, and shower. But the closet must be close to your home’s plumbing line.

However, most closet conversions only feature the basics; therefore, you will never have to worry about a tiled shower, cabinetry, or costly vanities. (4)

  1. Garage

Most homes have spacious garages for two vehicles; therefore, they can provide more options for design and spacing. And the fact that the plumbing and electric lines of most old houses flow through the garage is a bonus. But make sure you install a window to take care of the high humidity level that can damage your walls.

  1. Bedroom

Another famous option for homes with several rooms is converting one of them into a classy bathroom. This option will provide you with more than enough space for your vanities, and you can even add an ensuite. You can also partition one of the vast bedrooms into a bathroom.

  1. Other Options

Homeowners with long hallways can also convert them to full-size or half bathrooms. You can also install a bathroom under the staircase or in the basement. Unfortunately, the basement will also be affected by the high humidity levels, so you must install a window.

How Big Should My New Bathroom Be?

A functional bathroom can be as small as 34sq. ft. and still feature some of the latest vanities, bathtub, shower, and toilet. (16) However, one of the most common layouts for a functional bathroom with a bathtub, shower, toilet, and vanity is a nine by 5-foot space. This narrow space can help lower your expenses since all the plumbing lines will be in one wall. (17)

A vast master bathroom should have a space of about ten by 12 feet or more. It should be huge enough to feature a bathtub as its focal point and a space dedicated to a walk-in shower with a glass enclosure. (17) And if you don’t have enough space, you should look for space-saving fixtures like a corner basin, bathtub shower combination.

Plumbing and Electrical Works for a Bathroom Renovation

When renovating your old home, all the electrical and plumbing jobs must meet the current codes. And with an old home, it means that you might have to update the entire house. Therefore, you must determine all the needed upgrades before you even start your project.

Homeowners with septic tanks must determine if their systems can support an additional bathroom; if it can’t, then you should be ready to do an expensive upgrade. But the best option when adding a bathroom is tying it to your current plumbing.

Therefore, you have to ensure that the new site is opposite or on top of an existing bathroom. It is crucial for toilets, as installing a new vent stack can be quite costly. (18) Bathrooms on the first floor with a crawl space or basement can be easily plumbed, whereas those with a slab foundation will require you to break the concrete.

A basement bathroom that is below the sewer line will require a powerful pump.

Proper Ventilation in a Bathroom

A bathroom with a shower and/or bathtub must be well-ventilated. Therefore, it should link to the exterior wall, where you can add a small window. If that is not possible, then you should add a fan to help lower moisture build-up.

A fan is mandatory even if your bathroom has a window. (18)

Smart Storage Ideas for the Bathroom

With the bathroom being where everyone in your home cleans up, you must make it as tidy as possible. Therefore, you should try as much as possible to make the most out of your small bathroom space. You can add stick hooks for hanging robes and towels.

An over-the-door shelf can be an excellent option for people without linen closets. Over-the-door shelves are ideal for storing towels, but make sure you have a step stool nearby. (19) Another option that is quite common among homeowners is the sink built-into with countertops, drawers, and cabinets.

Lighting for a Bathroom

The bathroom lighting must provide the necessary illumination for anyone to take care of his/her daily functions. After all, a well-lit bathroom can lower the risk of accidents. So here are a few things to consider:

  1. Get Rid Of Vanity Shadow

You should try and get rid of vanity shadows, especially on the grooming table. The shadows can affect you when applying your makeup or shaving your beards. So instead of a single light on top of the mirror, you should add two wall-mounted fixtures on both sides of your mirror at eye level.

  1. Fancy up Your Tub

Accent lighting like a mini-chandelier over your tub can offer a warm glow and dress up your space. It can also help make your tub stand out, especially since it’s the focal point of your bathroom. Chandelier light is a decorative light that can add interest to your bathroom.

  1. Light up the Footpath

Some toe-kick lightings under the base of your cabinets can light up the path at night. This light is usually hidden under the cabinet and countertop and can allow you to navigate at night easily. (20)

Bathroom Design and Layout Considerations

Before you even start designing your bathroom, you should ask yourself the following questions:

  • Who will be using the bathroom? If it’s for two adults, will they be using it during the morning rush hour? Will people with disabilities or children use it? Will you wash your pets in that tub?
  • How will the bathroom be used? Will you be applying your makeup or shaving your beards there, or will your new bathroom host the laundry room.
  • Where will all the fixtures be located? How you arrange your bathroom will determine the amount of storage space you can create.

With answers to the above questions, you can start planning your bathroom and even determine the size and type of fixtures needed.

If it’s a full-sized bathroom, then it should have enough space for all your fixtures. When working with a small narrow space, you should line up your shower, toilet, and vanity next to each other. And to create more space, you can install a vast shower instead of a tub shower combination.

To personalize the space, you should go for contemporary floating vanities instead of the traditional shelf cabinets. A console-type sink can help open up the floor space making your bathroom feel roomier. If the other bathrooms have bathtubs, then you should add a large shower in your new bathroom. (17)

But make sure you leave more than 36 inches wide pathways all around your bathroom. And if you plan on sharing the bathroom, then the space in front of your sink should be 42 inches wide. So make sure you leave more than enough space in your design. (21)

Placement Tips for the Bathroom Layout

  • Tubs: Whether you will use it frequently or not, the tub the focal point of the entire room. So make sure you leave more than enough space in front of your bathtub.
  • Sink: you should easily access the sink once you enter the bathroom.
  • Shower: position the shower so that over-spray and moisture don’t reach the other parts of the bathroom. Therefore, adding a shower enclosure is mandatory in this scenario.
  • Toilet: the water closet should have its small room or place out of direct sight. And make sure you put it near a window or add exhaust fans.


Can You Add the Bathroom Anywhere in Your Home?

Yes, you can add the new bathroom anywhere in your home as long as you can afford it. But if you’re working on a budget, then you should place it near your home’s plumbing lines.   

How Can You Lower the Cost of Adding a New Bathroom?

The best way to reduce the project’s overall cost is to recycle some of the materials in the house. You can lower the plumbing cost by placing it near an existing bathroom. But most importantly, try and do some of the work yourself or even be the plumber’s and constructor’s assistant.

Do I Need Permission to Install a New Bathroom in My Old House?

Just like with refitting your kitchen, you might not need planning permission unless your old home is one of the listed buildings in your area. After all, a listed building is an architectural or historical feature protected by the state, and adding a bathroom will alter its design.

Final Thoughts

Adding an extra bathroom can increase the value of your home and make it more functional. But when dealing with an old house, you will have to be very careful as it contains numerous outdated features. So you should be ready to spend more cash on upgrading your plumbing, electrical wiring, and even adding a new septic tank.