A single-family home with an attached mother-in-law suite, with trimmed shrubs and a vibrant green lawn out front.

What Is a “Mother-in-Law Suite” and Should I Build One?

A mother-in-law suite is a private living space within or on the property of a single-family home. Also referred to as an in-law suite or simply just a guest house, this home addition is popularly used to host your older relatives — such as — your mother-in-law. 

The full function and potential of a mother-in-law suite are flexible. Usually, it must include one bedroom and a full bath to count as a living unit, as opposed to just a bedroom or office. Others may say it also requires a kitchenette and sitting area, so it can function as a self-contained living area, like a studio apartment. 

There are many ways to incorporate a mother-in-law suite on your property. From building ground-up to finding a pre-engineered metal building or converting a storage unit into living quarters, the options range in style, comfort, and prices for detached buildings, among other considerations. Whether you choose just to include a bed and bath, or a kitchenette and sitting area can affect those considerations too. 

What Are Mother-in-Law Suites Used For?

In many cultures, it is historically common for several generations to live together. In America, this trend has been on the rise since the 2008 economic crisis. According to a Pew Research survey, 64 million Americans live in multigenerational homes as of 2018. 

The same research study found that bunking with family members is most common among Asian, Hispanic, and Black families, and less common with White families. Younger adults and older adults make up the bulk of these types of households. Suggesting that they are the people most commonly found in a mother-in-law suite or guest house. 

After all, a mother-in-law suite is great for saving money by having family members all live under one roof. But these guest houses could also even be used to rent out and earn extra money — whether they’re rented to family or through a service such as Airbnb. 

A third reason for having a mother-in-law suite is to host your older relatives that can no longer live on their own. This style of living arrangement can provide that autonomy a parent or grandparent needs without their child or caretaker having to worry about their every move. 

Why Should You Add a Mother-in-Law Suite?

Like anything, there are an array of potential benefits and drawbacks to adding a mother-in-law suite to your property. From having more space to less privacy, you’ll have to decide if building one is right for you and your family.

Potential benefits of a mother-in-law suite:

  • More space: An addition to your home such as a mother-in-law suite does mean having more space for guests. Whether you’re hosting guests long-term or short, you’ll always have a place for them to stay. 
  • Additional storage: If you’re not using your mother-in-law suite to host guests, you can use it for additional storage space. 
  • Room to grow: If you have a senior relative who may need assisted living in a few years, you may want to consider adding on a mother-in-law suite. 
  • Save money: You may end up saving more money by putting up your senior relative on your property than in a retirement community or assisted living center. The same goes for young adults with or without college degrees.
  • Make money: Whether or not you decide to rent out a mother-in-law suite, having it on your property guarantees you a source of income. If you lose your job, or simply want a second source of income, a rental property can do the trick. 

Potential drawbacks of a mother-in-law suite:

  • Less privacy: Of course, hosting relatives or other guests on your property can mean less privacy. Common areas such as the backyard, laundry, or even the kitchen may end up being shared. If you or someone else in your household doesn’t get along with certain relatives, putting them up at your place may not always be in your best interest. 
  • High utility costs: The utility costs are going to be inevitably higher, the more people there are living on your property. You can charge for utilities or pay them yourself, but it is good to stay aware of the costs.
  • Zoning and building codes: During construction, you’ll have to keep in mind local zoning and building codes. These will dictate what you can and cannot do on your property. 
  • Insurance costs: You’re also going to need to take a look at what your insurance covers. If it doesn’t cover an additional dwelling, you may need to insure it separately. 
  • Additional upkeep: Lastly, you’ll have to remember that more space in your home means more upkeep. Weekly cleaning chores are going to take longer than they did before.

How Much Does It Cost to Build a Mother-in-Law Suite?

The cost of building a mother-in-law suite varies. For one, it can depend on the building materials you use, such as wood, steel, or even sustainable materials. These range in price, with steel typically being the most affordable material, as well as one of the most sustainable. 

Whether or not you build off of your existing home or construct a new building elsewhere on your property also affects the cost. For additions to the home, wiring and plumbing can be set up through existing infrastructure. A detached living space may be more costly to power given its location away from the home’s existing wiring and plumbing.  

The city or town you live in, insurance, or zoning or building codes also may affect the cost. Make sure you do a full rundown of the costs before starting construction on your new mother-in-law suite.

How Much Value Does a Mother-in-Law Suite Add?

One of the biggest considerations homeowners make when deciding whether or not to add any addition to their house is: how much value will it add? If you’re thinking about the resale value of your home, you can rest easy knowing that a mother-in-law suite is an upgrade that can increase home value.

Of course, how much value it can add depends on a variety of factors. Where you live and how intensive of a build the mother-in-law suite is can affect the value add.  

How to Add a Mother-in Suite to Your Home

Below is a list of considerations you must make when adding a mother-in-law suite to your home:

  • Check local laws: Before doing anything, you should check your local zoning and building code laws. These dictate what you can and cannot do on your property.
  • Find the right space: Look for a space in your home or your property that is detached enough to provide some level of privacy. You may also want to find a space on level ground to avoid the costs of excavating land. 
  • Use the right materials: A couple of considerations to make when deciding what materials to use may include its sustainability, durability, cost, or location. Wood and steel are two popular choices for building a mother-in-law suite.
  • Hire contractors and get price estimates: Unless you’re looking to build the suite yourself or buy a premade building frame, it is wise to check out contractors and get price estimates. This way there may be fewer surprise costs down the line. 
  • Check taxes: Adding a guest house typically increases taxes on your property. Once your addition is constructed, make sure to calculate what you owe on it each tax season. 

While there is a lot to consider, at the end of the day, adding a mother-in-law suite to your property may just be the best choice for you and your family.