Adding a ‘Mother-in-Law’ Apartment

A mother-in-law apartment, or a mother-in-law suite, is like a guest house or suite made for your in-laws or parents. It’s usually attached to the house or located on the same lot as the adult child’s house. Instead of letting them take a spare bedroom in the house, you provide them a suite complete with a separate kitchen, bathroom, bedroom and living space. These could be a finished basement apartment, a converted garage or a detached guest house.


If you feel that living in close to you would be a better choice for your parent or in-law and you have the budget to build it (or buy a property that has an additional dwelling), then by all means go ahead. But it isn’t right for everyone also if the older adults would prefer to stay in their current home for the rest of their lives. Read more to assess if adding a mother-in-law apartment is a great choice for your family.


Adding an in-law apartment or purchasing a home with one has its own benefits.

1. Low cost-alternative for pricey housing expenses

More Americans today are living in multi-generational homes, as assisted living costs continues to rise. Older Americans are choosing to move in with their children and grandchildren. Having a mother-in-law apartment can help house a live-in aging parent or family member or a live-in nanny. This is can save you expenses for having to pay for their housing.

2. Quality time with grandparents

Having your parents nearby is a great way to strengthen the bond of your children with their grandparents. Your kids can spend plenty of time with their grandpa and grandma, and they would probably love to see your kids more often. It would also be a great help for you, since you won’t need to hire a babysitter when you need one. They’re family so you can trust them easily with your kids.

3. Increased comfort and happiness

An in-law-apartment provides a private space for your parents or in-laws while living in close proximity to their loved ones. Many seniors living alone or living away from their children – especially those with deceased or estranged spouses – can become lonely and depressed. Letting them live close to you can help ensure they are living a happy retirement. If they have mobility issues or health problems, you can be of assistance easily while keeping your privacy as a family.

4. Privacy while keeping close company

Sometimes, you’re willing to “adopt” a parent or in-law can because you love them, you want to keep them cared for, and you like your kids to be close to them. But at the same time, you kind of don’t want to, because they can make you crazy. Some may get in the way of your family issues and affairs, and letting them live with you under the same roof can give them more leeway to do that. Providing them a separate place to live while in the same lot can solve that problem. And usually, they want the privacy from time to time, too. Younger children can be too much to handle for the elderly, and having a separated space can give them peace and quiet.

5. Additional storage space

If you don’t have a garage or storage unit, the vacant in-law apartment can serve as your storage area where you can place extra furniture, large sports equipment and some seasonal items that don’t fit your storage.

6. Guest house or other alternative use

If your in-law suite or apartment becomes vacant, it becomes a great space for holding a bed-and-breakfast for your guests. Turning it into a guest house will surely impress your friends and extended family, and they would love staying at your place (if that’s what you want). This can also serve as a living quarter for your child who recently graduated college and just moved home. This can provide them a private space to while transitioning from college to being a young professional. Or you can use this place as a rental, so you can earn from it as you rent it out.

7. Increases home value

Having an in-law suite will surely boost the value of your home. An additional space besides your primary house will result to a higher listing price if you decide to sell your house one day. There are home buyers who are willing to pay extra for this kind of suite. A study found out that an in-law suite and a finished basement were desired by most home buyers.


Mother-in-law apartments aren’t right for everyone. Here are some disadvantages that may make you not want this suite.

1. Additional utility cost

Since you’re adding a separate dwelling area, you would need to add a separate heating and cooling appliances, which will add to the cost of your electric bills. You may also have a higher water bill.

2. Additional maintenance

There will be more day-to-day maintenance if you choose to have an in-law apartment. You’d be cleaning additional toilets and gutters, vacuum more floors, replace more bulbs or curtains and the like. It can be expensive and time consuming. Some find that the additional maintenance is not worth the benefits, and they would rather offer a separate bedroom for the elderly instead.

3. Dealing with strict building codes

Building a mother-in-law suite from scratch may mean exploring your city’s zoning regulations and other building rules. You’ll need to check first with the authorities if you’re even allowed to build an additional residence in your own lot. Some zoning regulations and rules may not allow building secondary dwelling. You may also need to hire a licensed contractor to assist with the needed permits, paperwork and construction needs.

4. Insurance costs

Also, you need to check whether or not your homeowners insurance policy would cover the additional dwelling unit. If it’s not, you may need to pay more for your insurance. And if you plan to rent it out to tenants who aren’t your family, you may need to buy additional insurance so you can protect your own home.

Things to consider before building an in-law apartment

If having a mother-in-law apartment works best for your family and you want to build one from scratch, here are the things to consider before doing it:

1. Space

The first thing to consider is space. If you have a spacious lot that can accommodate a small yet comfortable dwelling and at least one parking space, then you can consider it. You may also have a spacious garage or basement space that you don’t use, and you can transform it as a granny flat. But if space doesn’t allow, perhaps providing an additional room is the only thing you can do.

2. A trustworthy contractor

It’s best to choose a contractor who has built in-law suites before. Or perhaps look for an aging-in-place specialist. Contractors like them can be very helpful in the building process, since they could open you to ideas and advices to make the apartment as functional and as comfortable for the elderly as possible.

3. Local building codes

As mentioned earlier, you need to check local building codes before you can add your in-law apartment. Building this may need separate permits, or it may be banned by your local zoning rules. Requirements for an in-law apartment include:

  • Using the same lot or property where the main house is built
  • A separate entrance to the secondary dwelling
  • Access to parking, such as a driveway or garage
  • Separate water and sewer connections

4. Parent or in-law’s current and future needs

Does your new elderly have special needs, like grab bars for the bathroom or bedroom, wheelchair accessibility or space for medical apparatus? Once you ask them to move in, they may plan aging on the in-law apartment. Make it as comfortable as you can for them.

5. Separate utilities

Make your parents’ or in-law’s utilities separate from the main house so you can easily switch it off if the space ever goes unoccupied. Also, separating would help if you plan to rent it out for tenants in the future – this way you can split the bills without hassle.