How to Add Another Bathroom to Your House

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Planning the Project

If you have decided to move forward with adding a shower to your half bath, the next step is to understand the layout of your home and visualize the end product. Ask practical questions, such as:

  • Is the bathroom adjacent to a linen closet that can extend the bathroom? Or can you cut into a bedroom to make more room for a shower and/or tub?
  • Is there unused hallway space you can take advantage of?
  • Is the small bathroom is spacious enough for a standing shower?

Of course, creating a bigger bathroom is desirable, but how much extra will it cost? Having an experienced contractor is crucial during this step. A pro will have the experience to visualize the project and determine if the walls are safe to cut into without interfering with the integrity of the home. They will also know how to complete the project up to code and pull permits in order to get it done correctly.

How Did Powder Room Become a Synonym For a Half Bath?

You may be wondering why a half bath is often referred to as a powder room.

The term “powder room” started in the 1920s when people thought women using a bathroom to relieve themself was considered improper.

Instead, they would use the word powder room to sound more ladylike. A few items that are often found in a half bathroom include a pedestal sink, hand towels, and towel racks.

A powder room is a small bathroom even in larger homes.

Half Bath Dimensions

Photo by Peter Johnston, Architect, PC

A half bath needn’t be large. You will have enough space if you can find a spot in your house that’s about 3 to 4 feet wide and 6 to 8 feet long. If it’s any smaller, it will be uncomfortable for people to access. A larger half bath is unnecessary, and it’s not likely that you’d find that much “extra” unused space in your house.

Shown: This parlor bath in New Jersey is able to capture a hotel spa look in a limited space of 40 square feet.

Tips for Revamping a Current Bathroom

Whether you want to improve the value of your home or improve the way you feel about your bathroom, you can also consider giving an existing bathroom a facelift. This is a more affordable option than adding a whole new bathroom and can still achieve some great results. Consider these tips to help you revamp a current bathroom:

  • An affordable way to give your bath, shower or sink a new look is to replace the faucets with ones that have modern appeal.
  • Painting is a tried-and-true means of giving any room a fresh new look. You may also want to consider an accent wall with a fun wallpaper, tile or wood planking you love.
  • No one wants a dimly lit bathroom, especially at the vanity where you likely spend time getting ready. You also don’t want to have outdated light fixtures. If you’re dissatisfied with your current light fixtures, replacing them with bright ones you love is a great move.
  • The mirror over your vanity may need an update if it’s a plain, builder-grade mirror. Instead of replacing the whole mirror, consider adding a frame to give the mirror a more stylish look.

Areas in your home that you can add a half bathroom

An important consideration when installing a new bathroom is where to place it. The beauty of a half bath is that it is much smaller than a traditional bathroom, giving you a greater deal of flexibility.

Here are some common areas in your home where you can add a half bath. A half bathroom adds a great deal of versatility to your home. Depending on where you install a half bath


A half bath is a great addition to a basement home office or child playroom. A half bath installed in the basement provides a more conveniently located bathroom out of the usual foot traffic. Also, the average cost to add a basement is around $10-15,000.

However, if you add the basement under an existing

However, if you add the basement under an existing bathroom, you can save anywhere between $1-2,000 in plumbing expenses. The only drawback to a basement half bath would be the ventilation and sewage-ejector system of your home.

Ensure that this system is properly routed through your home so that your wastewater can effectively travel up and out of your basement area to the proper channels. 


A closet bath provides a great choice as it remodels a small storage space and repurposes it. This cuts back on installation costs as you are adding to an existing space. Additionally, closets are conveniently placed in many homes, providing a natural recess to install a bath.

Keep in mind that the average cost to install a closet bath is anywhere from $5-15,000. Depending on the size of the existing closet and proper ventilation, it will be necessary, especially given the smaller space. 

Under a Staircase 

Similar to closet space, the storage area under a staircase is another good choice for a half bath as it repurposes an existing space. Many staircases have an empty space that many homes use for storage or a pantry, which makes it a logical area for a small bathroom.

Before installing in this area, ensure that space is around 25 square feet with a minimum height of 5 ft to keep with local building codes.

Additionally, ensure that proper ventilation can reach this bathroom through either a window or fan. The average cost for a stair installation starts around $3,000. 

Convert Laundry Room to a Half Bathroom

A laundry room can also provide a great location for a half bath. Many laundry rooms tend to have a large amount of space available, with existing plumbing already installed.

With plumbing costs lowered and the laundry room’s location typically out of the way of heavy foot traffic in your home, a laundry bathroom is a logical place to install a bathroom. The laundry room bathroom’s average cost would be anywhere from $5-12,000 depending on size and materials.  


A popular location, the long hallway in many homes provides a great deal of space for a bathroom to be installed. Windows can easily be added to this location, providing great ventilation compared to other areas.

The hallway also provides a convenient location that allows guests to enter and exit discreetly when using the bathroom. Depending on the location and materials, a hallway bathroom will run anywhere between $5-15,000.

A half bathroom provides your home with a great value-increasing your home’s price while offering a very versatile bathroom for you and your guests. But before you install one, remember to be cost-effective. Consider your existing water lines, drains, and electrical circuits to determine the best location for this bathroom.

Lastly, remember to strike a balance between luxury and budget so you can find the right look for your bathroom without breaking the bank. 

What are the Benefits of adding a Half Bathroom?

Installing a half bathroom in your home will ultimately increase the value of your home. On average, installing a half bath will add 10% to your home’s value.

This bathroom also provides a convenient and easy to access bathroom for guests and family members. Since it is a half bath, it is much easier to clean and maintain than a larger bathroom as there is only a toilet and a sink. 

What is a 1/4 Bath

Even less common is a 1/4 bath. Quarter baths are usually tiny and have only one component. Most of the time will contain just a sink for someone to freshen up or clean their hands.

They can typically be found in basements. If someone has installed a pool but does not have a finished basement, it makes for a convenient place to dry off and change. It is a good option to keep water out of the general living area.

Upgrading from a 1/4 bath to a 1/2 bath is usually simple as long as you’ve added rough plumbing. You would just need to add a toilet, and the room would be considered a half-bath.

Demolition While Adding a Shower to a Half Bath

As you convert your half bath to a full bath, your contractor may have to tear down a wall to expand the footprint of the bathroom. Before they do this, you will need to shut off the water to avoid a slip and slide situation. Depending on what the plan is, they will also have to take out light fixtures to either be restored or replaced once the new shower is installed.

The shower installation is usually the priciest part of the whole endeavor, as it requires plumbing, drainage, a pan, water-resistant drywall, and fixtures. These need to be done correctly to avoid leaks and water damage.

The time to add a shower to a half bath will vary on how extensive the renovation project is. The whole process can take anywhere from two weeks to a month. Your contractor will be able to provide a more concrete answer, based on your particular space, when you discuss the plan.

Where to Add Your New Bathroom

Your first roadblock may be that you don’t think y

Your first roadblock may be that you don’t think you have enough space for a new bathroom. If you’re wondering, “where can I add a bathroom,” it may surprise you to learn that you can build a half bath in just 3-by-5 feet of space! With 25 square feet, you can fairly comfortably fit a sink, toilet and shower, and with just a little more space, you can have yourself a full bathroom with a full shower and tub.

Where will you put your new bathroom? As long as you have a little available space, access to sufficient electrical outlets, ventilation and adequate sound insulation, you can sneak a new bathroom almost anywhere in your home. It may feel like you don’t have any available space to spare, but there’s a good chance you just don’t know where to look. Secret extra space is scattered through many homes, in areas such as:

  • Hallways: If your hallway extends all the way to the end of your house, possibly terminating in a window with no rooms on either side, you have the perfect location for a new bathroom.
  • Closets: Do you really need all that closet space? A large walk-in closet can often be converted into a new bathroom with just a few minor adjustments. Do you have any adjoining closets? Knock out the wall between them and you should have just enough room for a half bath.
  • Bedrooms: If you’ve got a large enough master bedroom, you may have a chunk of space you’re not using. Partition off that space for your new bathroom.
  • Existing bathrooms: You may be much better served with two small bathrooms than one huge one. Add the necessary fixtures to each side and cut that bathroom in half!

How Can You Add a Half-Bath to Your Home?

There are many ways you can add a half-bath to your home. You may want to fit it into an oversized storage closet or split a large full bath into a half bath and smaller full bath. Nevertheless, keep in mind that the space for your half-bath should not be necessarily large. A space about three to four feet wide and six to eight feet long should be enough. 

For budget reasons, you may want to install your half-bath close to existing water and sewer connections. Fixtures, including sinks, should be hooked to existing plumbing lines. If your house is built on piers or over basements, new plumbing lines can be placed below the main floor. However, houses built on slab foundations may require jackhammering and patching to connect the plumbing lines to the new space. 

Remember that adding a half-bath or any bathroom type requires both design and plumbing skills. Thus, you must hire a professional bathroom remodeler for the task. Pros will guarantee the success of your bathroom space. 

If you’re considering adding or remodeling a half-bath in your home, put your trust in Bay Valley Contractors. We offer quality home improvement services, including gutter installation and more. Call us today at (925) 705-7889, or fill out our contact form to set an appointment.