How to Build a New Bathroom Using Your Existing Plumbing

If you’re dealing with limited bathroom space and need an additional one or two bathrooms, adding a new bathroom to your home is an excellent solution. A downstairs half bath can save you the hassle of constantly going upstairs to use the bathroom.

Alternatively, you might want to consider adding a small bathroom to your outdoor kitchen and pool deck area, making it convenient for you and your guests to shower after swimming and during BBQ cookouts or pool parties. 

However, before starting any construction work, it’s important to carefully consider various design aspects involved in adding a new bathroom to your home.

Where are the existing plumbing lines and electrical wiring?

To add a new bathroom to your home, you’ll need to run plumbing, drainage system lines, and electrical wiring to the new bathroom. It’s essential to select an area in your home that has easy access to each of these components. Ideally, you should choose a location that makes it easy to extend existing plumbing and electrical wiring to the new bathroom.

For example, if you want to build a bathroom on the opposite side of the wall where your laundry room is located, extending plumbing and electricity from the laundry room would be relatively straightforward. However, if you want a bathroom attached to your bedroom, but the existing bathroom is on the other side of the floor, you may need to run plumbing from your kitchen to your bedroom to create the master bathroom you desire.

Remember, the location of existing plumbing doesn’t necessarily have to be adjacent to the new bathroom. As long as the plumbing lines are close enough, you can save on construction costs. Even if there’s no plumbing nearby, you can still build your dream bathroom by having new plumbing and drainage system lines installed, although this will increase the project costs.

Where will the new bathroom be located?

There are various locations in your home where you could potentially install a new bathroom, including:

• Closets: If you have a decent-sized closet on the main floor that’s not being used, you could convert it into a bathroom to get the extra space you need.
• Hallways: Unused spaces in your hallways, such as a dead-end with no adjoining doors in a 5×8 foot area, could be transformed into an additional bathroom.
• Existing Bathrooms: If you’re not satisfied with your current bathroom layout or features, you could consider extending a small bathroom into a closet to make it larger. Alternatively, a larger bathroom could be divided to create two smaller bathrooms.
• Bedrooms: Extra space in your bedroom, such as a corner or additional closets, could be utilized to build the master bathroom you’ve always wanted.

How will the new bathroom be ventilated?

Your new bathroom will need a vent pipe for the toilet and bathroom fan. Be sure that the room has easy access to an exterior wall or the roof. If roof access is hard, we can install a vent pipe and exhaust fan through an exterior wall. 

Depending on where you install your new bathroom, you may be able to use existing vent pipes and fan lines. 

10 Steps to Build Your New Bathroom

After deciding on the location for your new bathroom, you will be one step closer to commencing your renovation. Before you begin, it’s essential to plan the bathroom’s layout and specify the installation positions of the toilet, tub/shower, and sink. This design will also aid in identifying the required materials and estimating the project’s expenses.

Step 1: Schedule an in-home consultation with a bathroom plumbing professional.

It’s recommended that you seek guidance from a bathroom plumbing expert to confirm the whereabouts of your household’s current plumbing and drainage lines. This step is crucial to ensure that you can install plumbing in the desired location of your new bathroom. Your plumber will be pleased to offer recommendations and a complimentary quote for installing the new plumbing.

Step 2: Prep the room.

Once you have determined how to run plumbing to the new bathroom, you can begin preparing the room. The extent of the preparation work needed will vary based on the location of the new bathroom.

If you are converting a closet, the first step is to essentially strip the space. This involves removing the existing shelving, flooring, and any drywall in areas where plumbing lines must be installed.

On the other hand, if you plan to build a new bathroom by enclosing an open space, such as the end of a hallway, you will need to remove the flooring and drywall where the plumbing will be installed. Additionally, you will need to construct framing to enclose the area.

Step 3: Install vent and drainage system lines.

Having a professional plumber install the vent and drainage system lines is strongly advised, as you want to ensure they comply with current building codes. Moreover, your homeowner’s insurance may mandate that a certified professional completes the work to qualify for coverage. Your drain line installation should also include the bathtub, sink, and shower plumbing.

Step 4: Install water supply lines.

Once the vent and drain lines are in place, the next step is to install the new water supply lines. It’s essential to have separate lines for hot and cold water. However, if you prefer to run a single cold water line, you may consider installing a tankless water heater in the bathroom to provide hot water.

Step 5: Install electrical wires and outlet/switch boxes.

If your plumber isn’t certified to carry out electrical work, it’s recommended to hire an electrician for this phase. It’s crucial to ensure that the wiring, outlet/switch boxes, and other electrical components meet the required code standards. Additionally, you may require a new breaker to prevent the overloading of the existing ones. This phase also presents an ideal opportunity to have any ceiling light fixtures and vent fans installed.

Step 6: Hang drywall and paint the walls.

With all the vent, drain, plumbing lines, and electrical wiring installed, it’s time to put up drywall. Be sure to create openings for water supply lines, electrical outlet/switch covers, and wiring for wall-mounted light fixtures. Once the drywall is in place, it can be sealed and painted.

Step 7: Install the bathtub or shower.

It’s recommended to have your plumber assist with the installation of your bathtub or shower since you’ll need to connect the plumbing and drain lines, as well as the faucets and fixtures. If you’re building a shower enclosure, this is also when you should take care of this task.

Step 8: Install the flooring.

At this stage, you should install the flooring for your new bathroom, ensuring to leave an opening for the installation of a floor-mounted toilet if necessary.

Step 9: Install the toilet.

The installation of the toilet should be carried out after the flooring is installed, regardless of whether it’s a floor-mounted or wall-mounted toilet.

Step 10: Install the bathroom cabinets, countertop, sink, and mirrors.

As you near the completion of your new bathroom addition, the final step is to have your plumber install the sinks and fixtures and connect the water supply and drain lines. If you opted for a tankless water heater in the bathroom, this is also the time to have your plumber install it, especially if it’s being installed under a cabinet.

Finishing Touches

Depending on the bathroom design you created, you may need to add some finishing touches, such as:

• Hanging up towel bars
• Installing wall-mounted light fixtures
• Hanging up pictures/wall decorations

Once everything is completed, thoroughly clean your new bathroom and enjoy it! Don’t forget to take pictures at each stage, so you can share your new bathroom addition on your preferred social media platform.

If you need help installing new bathroom plumbing, drainage system lines, sink installation, or other plumbing requirements, don’t hesitate to contact MET Plumbing & Air Conditioning by calling 281-603-9949 today! We can also help you with running new air ducts for heating and cooling your new bathroom.