Half Bathroom to Full Conversion - Costs, Permits, and Designs

Why convert a half bathroom to a full bathroom?

First, let’s break down the difference between a half and a full bathroom. A half bathroom—also known as a powder room or guest bathroom—typically consists of just a toilet and sink. On the other hand, a full bathroom includes a toilet, sink, and either a bathtub, shower, or both. Adding a shower or tub to your half bath is the key element of converting it into a full bathroom.

Full benefits of a half-to-full bath conversion

• Increased home value: One of the most significant benefits of converting a half bath into a full bath is the potential increase in your home’s value. According to real estate experts, homes with more bathrooms—especially full ones—tend to sell faster and at a higher price. Adding a full bath can make your property more appealing to potential buyers, especially if your home has limited bathroom space.
• Convenience for larger families: If your household has more people than bathrooms, adding another full bath can be a lifesaver. Whether it's for kids rushing to get ready in the morning or guests staying over, a full bathroom adds functionality and ease.
• Better use of space: If you’re not fully utilizing a half bath and have room to expand, converting it into a full bath can be a more efficient use of space. This is particularly useful if the half bath is located near bedrooms, making it easier for guests or family members to have quick access to a shower.
• Customization and luxury: Maybe your half bath is outdated or just doesn’t fit your style. A conversion offers the chance to design a space that reflects your taste and adds a little luxury to your home. Whether you’re dreaming of a rainfall shower, heated floors, or simply more space to move around, this is your opportunity to make those dreams a reality.

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Key considerations when planning your conversion

Before diving into the project, there are several important factors to consider. These will help ensure the process goes smoothly and that you’re happy with the final result. Additionally, we'll discuss potential challenges you might face during the conversion and how to overcome them.

Space requirements

One of the first things you’ll need to figure out is whether you have enough space to add a shower or bathtub. The typical space required for a full bathroom is around 40 square feet. However, there are ways to make it work with less, depending on your layout and the fixtures you choose. Keep in mind that adding a shower stall requires about 15 square feet of space, and a bathtub takes around 30 square feet. You may need to steal some square footage from a neighboring room, closet, or hallway to make it happen.

Plumbing

Next up is the plumbing. Adding a shower or tub requires more extensive plumbing than a simple toilet and sink. You’ll need to ensure that your existing plumbing can handle the additional fixtures and that your water heater is capable of supplying hot water to the new setup. If your plumbing isn’t already nearby, you’ll have to run new pipes, which can add to the overall cost and complexity of the project.

Ventilation

Good ventilation is critical in a full bathroom to prevent moisture buildup, which can lead to mold and mildew. Make sure there’s adequate ventilation either through a window or an exhaust fan. If you're installing a shower or bathtub where one didn’t exist before, adding ventilation may be a necessary part of the process.

Electrical work

Don’t forget about the electrical work! Adding a shower may require new lighting, an exhaust fan, or even heated floors, all of which will need proper wiring and outlets. If your home’s electrical system isn’t up to code or can’t handle the additional load, you may need to upgrade your electrical panel.

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How much does converting a half bath to a full bath cost?

On average, you can expect to pay between $5,000 and $25,000 for a half-to-full bathroom conversion, including the costs of materials, labor, and any necessary permits. The lower end reflects budget-friendly materials and minimal plumbing work, while the higher end includes more extensive renovations and premium materials. While the best way to determine the project budget is to receive quotes from multiple qualified contractors, below is a breakdown of individual renovation elements that often go into converting a half-bath into a full. 

Cost of Adding a Shower to Your Half-Bath

If you’re looking to transform an existing powder room, you’re likely prioritizing space-saving solutions like a walk-in shower. As detailed in our guide, How Much Does a Walk-In Shower Cost?, adding a prefabricated shower typically costs between $600 and $2,500, while a custom-built shower can reach up to $5,200. These figures do not include the potential need for plumbing adjustments, which are often required when adding a shower to a half-bath and can add another $600 to $1,500 to your project.

Cost of Extra Waterproofing During Your Conversion

Converting a half-bath to a full bath means your space will be exposed to much more water, making thorough waterproofing essential. Full baths are especially susceptible to splashing and moisture buildup, particularly around showers and tubs. To prevent leaks, mold, and long-term damage, contractors apply waterproof membranes to walls and floors, seal all joints, and use materials designed for wet environments. Investing in proper waterproofing is crucial for the longevity and safety of your new bathroom. 

For most half-to-full bath conversions, homeowners should budget an additional $800 to $2,000 for comprehensive waterproofing, depending on the size of the room and the products selected.

Cost of Installing New Flooring

Upgrading from a half bath to a full bath almost always means rethinking your flooring. The addition of a shower or tub brings more moisture and foot traffic, and if you’re moving walls or expanding the space, your old flooring may no longer fit or match the new layout. Flooring that worked for a small powder room—like basic vinyl or wood—may not be durable or water-resistant enough for a full bathroom, where splashing and humidity are daily realities. Plus, if you’re adding new plumbing or moving fixtures, sections of the floor will likely need to be opened up and replaced.

For a typical 40-square-foot bathroom, budget-friendly flooring options like sheet vinyl or standard ceramic tile start around $400–$800 installed. Mid-range choices, such as porcelain tile or luxury vinyl plank, usually fall between $800–$1,600. If you’re looking for a high-end finish—like natural stone, marble, or custom tilework—expect to pay $1,600–$3,000 or more for the same space. When planning your half-to-full bath conversion, it’s important to select a flooring material that stands up to water, is easy to clean, and complements the overall design of your new full bath.

Cost of Moving a Wall to Create More Space

In some homes, the existing half bath simply doesn’t have enough square footage to comfortably fit a shower or tub. In these cases, moving or removing a wall may be necessary to create the space required for a true full bath. 

This process can be complex, especially if the wall is load-bearing or contains plumbing, electrical, or HVAC lines that need to be rerouted. The cost to move a non-load-bearing wall typically ranges from $2,000 to $5,000, while moving a load-bearing wall can cost $5,000 to $10,000 or more, depending on the structural work involved and the need for permits or engineering plans. 

Expanding the footprint of your former half-bathroom will also increase the cost of finishes, waterproofing, and labor, so it’s important to factor these additional expenses into your overall conversion budget. If you’re considering this option, consult with a qualified contractor to ensure the work is done safely and in compliance with local building codes.

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Building code and permit requirements

Converting a half bath into a full bath isn’t just a matter of picking out tiles and fixtures—it also involves meeting building codes and obtaining the proper permits.

Permits

Most bathroom conversions will require permits, especially if you’re moving plumbing, electrical, or structural elements. Depending on where you live, you may need permits for plumbing, electrical work, and general construction. Be sure to check with your local municipality to find out what’s required in your area.

Building codes

Building codes are in place to ensure the safety and functionality of your bathroom. For example, there are codes that dictate the minimum ceiling height, the distance between fixtures, and ventilation requirements. Working with a licensed contractor can help ensure that your project meets all local building codes.

Design and layout considerations

When working with limited space, good design is key. You’ll want to maximize every square inch to make your new full bathroom feel spacious and functional.

Small space solutions

Don’t let a small bathroom deter you from converting it into a full bath! There are plenty of creative design solutions to make a small bathroom feel bigger. Consider opting for a corner shower, which takes up less space than a traditional shower. You can also choose a wall-mounted sink or a floating vanity to free up floor space. Glass shower doors, rather than a shower curtain, can also create the illusion of more room.

For inspiration for your half-bath-to-full conversion, take note of this compact Brooklyn bathroom. It makes the most of its 40 square feet by leveraging many of the tips above, including the installation of a corner shower with glass doors. 

Choosing fixtures

The fixtures you choose will have a huge impact on both the style and function of your new bathroom. Consider the following when making your selections:

• Shower vs. tub: Do you want a shower, bathtub, or both? Showers take up less space, while bathtubs can be more luxurious. You’ll also want to consider who will be using the bathroom. A tub might be essential for families with young children, while a shower could be more practical for a guest bath.
• Toilet: Compact, wall-hung toilets are ideal for smaller spaces. They take up less floor space and have a modern look.
• Sink: A pedestal sink or a wall-mounted option can save space, while a vanity with storage might be a better option if you need extra storage.

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Materials and finishes

The materials and finishes you choose will determine the overall look and feel of the bathroom. Here are some tips:

• Tiles: Opt for light-colored tiles to make the space feel larger. Glossy finishes can also reflect light, giving the illusion of more space.
• Storage solutions: Maximize vertical space by installing shelves or cabinets above the toilet or sink.
• Lighting: Good lighting can make a small bathroom feel bigger and more inviting. Consider recessed lighting or wall sconces to brighten up the space.

Steps to completing a half-to-full bathroom conversion

While every project is different, here’s a basic rundown of the steps involved in converting your half bath into a full bath:

1. Plan and budget: Determine your budget, choose your design, and decide on the layout and fixtures.
2. Get permits: Apply for the necessary permits to ensure your project meets local building codes.
3. Demo the existing bathroom: Remove the existing fixtures and any walls or floors that need to be replaced.
4. Plumbing and electrical: Install new plumbing and electrical work for the shower or tub, lighting, and any additional outlets.
5. Install fixtures: Install the toilet, sink, and shower or tub. This may include tiling and other finish work.
6. Final touches: Add the finishing touches like paint, lighting, and accessories to complete the look.

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Trust Your Half-to-Full Bath Conversion to Block Renovation

Turning a half bath into a full bathroom is a smart way to add comfort, convenience, and value to your home. When done thoughtfully, this renovation addresses everything from space limitations and plumbing upgrades to waterproofing and design, transforming an underused powder room into a practical, inviting space for your household and guests. With the right planning and expert support, a half-to-full bath conversion can make daily routines easier and boost your home’s appeal to future buyers.

Block Renovation is here to guide you through every step of the process. We work with a highly selective network of experienced contractors who understand the unique challenges of bathroom conversions—whether you’re dealing with tight city spaces or older homes with complex plumbing. Our team provides clear communication, transparent pricing, and personalized guidance, so you can move forward with confidence. With Block, you get more than just a contractor—you get a trusted partner dedicated to making your renovation smooth, successful, and tailored to your needs.