Basement Bathroom - How to Build It the Right Way

To build a fully functional living space in your basement, experts recommend adding a bathroom or a half bath. Doing so allows people to use the bathroom without having to go up and down the stairs every time. “Doing so [building a basement bathroom] comes with major upsides, increasing the house’s market value and serving as an added feature to the primary bathroom,” says Stéphane Dubé, Summum Salle de Bain Inc. It’s all the more appealing when there’s a basement bedroom or home office.

But first, what are the specific challenges of building a basement bathroom? In this article, we explore everything you should know before undertaking this project, helping you plan and execute your basement bathroom project without a hitch.

Installing a Basement Bathroom

Source: Construction et rénovation ImmoZen Inc.

Consider the following steps when remodelling a basement bathroom:

• Remove all furnishings, including the bathtub, shower, toilet, vanity, etc.

• Strip the walls and ceiling of gypsum boards and ceramic tiles

• Upgrade the plumbing, drain, and electrical system

• Repair the flooring and walls if necessary

• Install the shower, bathtub, and gypsum boards

• Proceed with tiling and paintwork

• Finish by installing the vanity and remaining accessories  

If your current basement situation doesn’t already include a half bath or bathroom, note that it’ll make the task at hand a bit more complex. It can be done but makes for a more complex undertaking than simply building a bathroom on the ground floor or a half bath in an area where there’s existing plumbing. 

Building a bathroom in your basement entails quite a few additional steps compared to that of a ground-floor bathroom. The reason why is that you’ll need to bring your water supply line and drainage to the basement, complicating the project. 

Given that basements are notoriously humid and prone to poor airflow, having a decent ventilation and dehumidification system is paramount. As a result, such a project does involve a few additional stages, in addition to meticulously following the step-by-step bathroom building guide. 

Putting in a Basement Bathroom: Can You Install One Without Breaking Concrete?

Source: MTL Contractors

Plumbing and Piping (Shower, Bath & Toilet)

First off, to build a bathroom, choose a few plumbing fixtures and all the hardware that’ll be connected to the piping, namely:

• Toilet

• Bathtub and/or shower

• Sink

• Others (washer, bidet)

As per the law, solely certified plumbers can carry out plumbing and piping installations inside residential properties. This part of the project will no doubt be handled in collaboration with a contractor. When it comes to this sort of project, the best practice is hiring a contractor specializing in bathroom-building projects, ensuring their hired plumbing and electrical subcontractors are licensed. The contractor will most likely have to rip out the flooring and dig into the cement slab to install the necessary pipelines and drains. It’s a lot more demanding than doing so in a ground-floor room.

For customers looking to carry out such a project for the first time, make sure there’s a wastewater check valve and that the drains are planned. Overlooking this step increases the risks of sewer water backflowing into the basement in the event of a storm. If said elements aren’t already installed, allocate an additional amount in your budget for extra plumbing work.

Ventilation: A Must-Have to Extract Moisture

Installing a good ventilation system is crucial given that bathrooms are moisture-prone areas in which air tends to accumulate and contaminate.

There are three types of bathroom ventilation systems:

• Natural ventilation (doors and windows)

• Spot ventilation (exhaust fan that’s turned on and off, at will)

• Whole-house ventilation (continuous air renewal)

Check out these articles when considering bathroom ventilation systems:

• What to Consider When Choosing a Bathroom Fan

• How to Control the Humidity in Your Bathroom

Electrical System

On top of plumbing, a versatile and high-traffic area like a bathroom needs to be well-equipped, electricity-wise. Not only do you need decent lighting, but electrical outlets are needed to plug in various bathroom essentials (hairdryer, electric razor, etc.).

Bathroom electrical wiring has specific requirements due to its proximity to water. For safety, the law mandates that all electrical work be performed by a qualified expert.

Wall Treatments

The most sought-after materials include two-by-fours or two-by-threes to build partitions, anti-mould gypsum boards, or waterproof panels for walls and ceilings to prevent water damage. Shower stalls typically feature an acrylic or ceramic base, with a glass panel door and faucet. Next, the melamine vanity and linen cabinets with quartz or laminate countertops are installed, with a sink and faucet—all noteworthy options.

On the bathroom walls, paint, moisture-proof wallpaper, and/or tiles are often featured.  Consider the following before selecting a specific wall treatment for your new bathroom:

• Use bathroom-specific paints (check out this article: How to Choose Paint for Your Paint)

• The selected wallpaper has to be waterproof and installed properly, ensuring it doesn’t peel off due to high humidity

• Porcelain or ceramic tiles are really good options when it comes to wall coverings

• If your budget allows for it, lay marble or another type of natural stone on your walls (once again, all installations must be sealed)

Flooring

Before making any aesthetic-based decisions, make sure that your bathroom floor is safe, low-maintenance, and waterproof. Fortunately, there’s a slew of products and materials retailed that meet these standards. 

Here’s the best bathroom flooring:

• Ceramic

• Porcelain

• Laminate

• Vinyl

Find more detailed information in this article: The Best Types of Flooring for Your Bathroom. 

Storage

All bathrooms deserve just the right amount of storage cabinets and accessories. It’s vital to ensure the area remains, overall, tidy, ergonomic, and practical. Typically, the vanity (or sink base) is a bathroom’s storage epicentre. Adding a closet, shelving, and a linen cabinet is useful too. Some homeowners even go as far as hiring a carpenter to design custom storage furniture. 

The following article features different vanity models: Bathroom Vanity: How to Choose Your Sink Countertop.

Decoration

Let’s wrap up this section with a bathroom’s aesthetic aspect. It’s the perfect finishing touch that will make this cleanliness-dedicated space all the more pleasant for the rest of the house. 

There’s no such thing as limits or bathroom-specific criteria when it comes to decorating a bathroom. Ultimately, what it comes down to is personal taste and needs. Nonetheless, we typically advise homeowners to pay careful attention to lighting, light fixtures, and the room’s overall brightness.  

Here are some bathroom decor ideas to get you started:

• 10 Family Bathroom Ideas

• 10 Examples of Dark Bathrooms

• Master Bathroom: 10 Examples

What Kind of Contractor Should You Hire for Your Bathroom Project?

Source: Construction Rubix Inc.

Knowing you’ll need to hire experts for your project, you’re probably wondering whom to call. For this sort of project, hiring a contractor specializing in bathroom building projects and remodels is paramount, one with licensed electrical and plumbing subcontractors.

Several options are made available:

• Interior designer: This professional can sketch your bathroom plans, guide your choices in terms of materials, and even oversee the work if that’s what you want.

• General contractor: This type of contractor is licensed to carry out the work, from start to finish. As such, they can offer turnkey services.

• Specialized contractor: If you’d rather oversee the work yourself, you can hire various specialized contractors (plumbing, electrical, flooring, painting, carpentry, etc.).

To figure out which services best meet your needs, ask yourself what matters most to you: time, money, or both.

If your time is precious and you’re ready and willing to spend a certain amount of money for someone else to take care of the project for you, then the choice lies between an interior designer and a general contractor (or both in some cases).

However, in terms of money, you could have a bit more leverage over the budget if you hire specialized contractors. However, note that since you most likely have zero construction experience or lack a renovation skill set, the project could take longer than expected and unexpected expenses may arise. So, consider every detail meticulously!

How Much Does It Cost to Add a Bathroom in a Basement?

Source: WDK Management Inc

Building or renovating a bathroom calls for a significant budget. This is all the more true when the bathroom in question is in the basement; the complexity level is all the more real, too. “A budget for this sort of project hinges on several factors, such as room dimensions, materials, water and electrical lines, etc.,” specifies a Summum Salle de Bain Inc. contractor.

To give you a better idea as to the financial investment required for this type of project, Mr. Dubé explains that, “for a full bathroom [on an upper or ground floor], budget between $20,000 to $30,000, plus tax.” However, if the bathroom is in the basement, the budget looks a little different. "For a small basement bathroom [5 x 10 room, complete remodel, including walls, ceiling, bathtub, shower, countertop, toilet, new ventilation system, ceramic tiling, heating, and lighting], budget about $15,000 plus tax,” says the contractor.  

It’s hard to put a specific number to it, but we can still give you some ballpark figures to help you gauge the amount you’re likely to see when seeking out project quotes.

We’re talking about sums ranging from $4,000 to $30,000. The lowest price point is based on a small bathroom, outfitted with budget-friendly materials. On the other hand, if your bathroom is big and spacious, and you’d rather select high-end materials, your budget will easily skyrocket to $30,000, especially for a basement bathroom. “There are several challenges, including location, the year the house was built, service availability, and the customer’s budgetary expectations in terms of materials and dimensions,” explains Mr. Dubé.

You can use our cost estimator to help you crunch the numbers when the time comes. However, note that the latter won’t take into account any additional costs related to building a basement bathroom. As such, add $1,000 to the estimated amount.

Consider the Following Basement Bathroom Requirements

Source: CRC - Construction Rénovation Canada inc.

How to Make a Bathroom Less Humid

The entire bathroom has to be ventilated properly, but more so in the basement since airflow is already restricted there. Make sure to choose a quality ventilation system, one fitted with a decent dehumidifier. That way, you won’t end up with mould or mildew problems.

How to Add Light in Your Basement

Few and far between are basements flooded with natural light. As a result, you have to pick up the slack with artificial lighting, meaning selecting the right lighting fixtures. 

Where to Install Light Switches and Electrical Outlets?

There are certain criteria to follow when it comes to installing electrical outlets and light switches in a basement, considering the outlets must be fitted at least 12 inches (30 centimetres) off the finished floor. The light switches have to be positioned at least 48 inches (122 cm) off the finished floor.

Other regulations also apply when it comes to the wiring inside walls. A certified electrician will know how to proceed. 

Concept Idea: Why Not Add a Laundry Room?

A lot of homeowners choose to set up a laundry room in their basement bathroom. If the area in question is big enough to install the required appliances and all the necessary laundry products, it could be a worthwhile idea since it means all the plumbing is in a dedicated area.

Here are some articles dedicated to laundry room layout ideas:

• Laundry Room Design Ideas

• How to Set Up a Laundry Room in Your Home

We also suggest taking a peek at our Bathroom Renovation Checklist.

FAQ About Basement Bathroom Remodels

Do I need a building permit?

Yes, you’ll need to request a building permit in line with this project. It’s also really important that you receive the permit prior to green-lighting the work, otherwise, authorities have the right to halt the jobsite. 

For more information, check out our article Building Permit - Will You Need One for Your Home Renovations?

Do you need blueprints or an engineer’s plan to build a basement bathroom?

If your basement bathroom project involves a load-bearing wall whatsoever, you’ll need an architect or engineer’s plan. You don't need to hire an architect or engineer if your project doesn’t include structural features. 

Even though your project doesn’t include load-bearing walls, sketching out a plan is still mandatory, as you’ll need one when requesting a permit. In any case, it’ll make the whole process easier.

Is it hard to build a bathroom in a basement? Can I DIY my project?

Given the nature of the project, using a DIY approach isn’t recommended. Right off the bat, it’s much more complex than building a bathroom on an upper floor and, on top of that, the law requires you to hire a certified contractor for all electrical and plumbing work. Someone looking to undertake this sort of project will inevitably encounter a hurdle or two: “There are several challenges, including location, the year the house was built, service availability, and the customer’s budgetary expectations in terms of materials and dimensions,” explains Mr. Dubé.

You can always carry out a few of the steps yourself, like painting or setting up certain furniture pieces, however, the result may not be as appealing. As for the rest, it’s best to work with industry experts. 

How can I add depth to my bathroom?

To add depth to your bathroom, use light and neutral colours, hang a big mirror, ensuring the light bounces off of it, and prioritize large format tiles or diagonal tiling. A glass-panelled shower stall instead of an opaque shower curtain can also visually enhance the space.

What is the best flooring for a bathroom?

Ceramic or porcelain tiles are considered the most durable and water-resistant choices. Vinyl is a more affordable option that’s comfortable underfoot. Waxed concrete is favoured for its modern appeal and waterproofing properties.

Does a basement bathroom need a floor drain?

Yes, a basement bathroom usually requires a floor drain to prevent water buildup and flooding. Also, basements are more prone to moisture and plumbing issues. Adding a drain helps control humidity and prevent mould growth. In many areas, building codes may require a floor drain in basement bathrooms for safety and proper drainage.