In-Law Suite Ideas for New Jersey: Where, How, & Cost

Posted on:  March 11, 2024

The "in-law suite" offers homeowners a lot more than the name would imply! With an independent kitchen or wet bar, bathroom, and sleeping area, the purpose of your in-law suite is limited only by your imagination. Use your in-law suite for an aging relative to live safely and comfortably, an office, private lodging for weekend guests, a home gym, and more! 

But where should you place an in-law suite on your property? What is the best size of an in-law suite? What is the cost of building an in-law suite?

Whether you call it a granny suite, mother-in-law suite, accessory apartment, accessory dwelling unit (ADU), or secondary suite, you'll reap all of the benefits of this completely independent space.

MAR 24 JMC BLOG 2 In Law Suite Stock

What Is an In-Law Suite?

Essentially it is an apartment-type unit that has a bathroom, kitchen area, and sleeping area. It can range from resembling an open-concept studio apartment with a wet bar to a one-bedroom apartment with a separate living room and bedroom. While it may be accessible from within the main home, an in-law suite has its own doorway to the outside, so it's possible to come and go without entering the main home. 

A detached mother-in-law suite is a separate building, often with a walking path to the main home. This type of structure has plenty of benefits, including acting as passive income as a rental unit and is also referred to as an "accessory dwelling unit (ADU)." Keep in mind, however, that not all towns in Northern New Jersey allow for this exact type of addition, so check in with your design-build team or your local government about legal requirements concerning detached ADUs. 

What is the best size of an in-law suite? Because the size of each in-law suite depends on how you intend to use it and where it will be located, the average range is anywhere from 300 to 1,000 square feet.

Can I Build an In-Law Suite on My Property in New Jersey?

The great news is, yes—as long as your addition fulfills local requirements and laws. The things you'll need to consider as to where you'll build your in-law suite are: 

  • Where on your property would it make sense to build your in-law suite addition? 
  • Do you plan to rent out your in-law suite? (This is another consideration where checking in with your local government is crucial.)
  • What are the accessibility needs of the expected occupant?
  • What are the setback allowances on your property and are you willing to lose yard space to build your in-law suite addition?

What Is the Cost to Build an In-Law Suite in New Jersey?

The cost to build an in-law suite in New Jersey will vary on the size, location, and the features you'd like to include.

How Much Does It Cost to Convert a Basement into an In-Law Suite?

The cost to convert your basement into an in-law suite will greatly depend on the current state of your basement. A completely raw space will of course be significantly higher than if it is already finished with walls, flooring, electricity, and plumbing. Because the variables and associated costs are so varied, it's best to contact a knowledgeable design-build team to talk about your current basement and your remodeling goals. 

Building an in-law suite in your basement comes with several benefits. If your home does have a basement that's underutilized, this is your best option for creating an in-law suite. The majority of the structure already exists with the opportunity to build out a proper exterior exit to suit mobility needs. You also won't have to sacrifice any yard space. Finally, if your basement is already equipped with plumbing, electricity, and HVAC ducts, you can forego much of those expenses. 

How Much Does It Cost to Build an Attached In-Law Suite?

The cost of building an in-law suite attached to the home in New Jersey is similar to adding a primary suite and could be from $350K to $550K. Where your suite falls in this range will depend on the size and features you choose to include.

For example, a separate bedroom and sitting area along with a full bathroom and walk-in closet will be on the higher end and may even exceed it if you choose high-end finishes. On the lower end, expect a combined sleeping and living area and a smaller bathroom with a tub/shower combo. 

How Much Does It Cost to Build a Detached In-Law Suite?

Think of building a detached in-law suite like building a small home. This kind of structure could cost $400K and above and requires asking yourself several questions. Do you want to include a full kitchen or a kitchenette? Will the suite have a full luxury bathroom or something more modest? Would you like to include a private porch, smart home features for safety, and other added features? To get a clearer picture of what your in-law suite design goals will cost, or if a detached structure is legal in your area, contact a design-build team with experience in this kind of property addition


Where Else Can I Build an In-Law Suite Addition or Accessory Apartment on My Property?

We've already mentioned building out your basement, creating an attached in-law suite, and building a detached ADU suite. Where else could you create an in-law suite?

Build an In-Law Suite Addition Over the Garage

If your home doesn't already extend over your garage, it's as good as free real estate! It's an area that many overlook when planning an addition. In most cases, the square footage of the garage footprint is plenty of space for an in-law suite. If accessibility is a concern, an elevator is a common solution. This is also a great opportunity to make passive income as a rental unit if you also extend the driveway to add a parking spot. 

Convert Your Garage to an In-Law Suite

If your garage goes unused or is cluttered with boxes and equipment that could easily go into a shed, consider converting this space into an in-law suite. This is a great option for ease of accessibility and, like a basement, much of the structure already exists. 

Convert Your Attic to an In-Law Suite

The attic is yet another great option for building an in-law suite. Attics are known for their ability to be converted into unique and appealing living spaces. This space is particularly great for an office, gym, or as an independent living space for an older child or another family member. Converting an attic will likely need additional insulation to keep the space from getting too hot during the warmer months. Keep in mind, however, that the awkward ceiling angles can cut into usable square footage. 


Is a Mother-in-Law Suite a Good Investment?

For some, spending up to hundreds of thousands for an apartment might seem like an unnecessary expense. However, there are several ways to look at this as a major financial benefit.

Save on Assisted Living Costs

The average cost for a private nursing home room in New Jersey is around $12K per month. This means if you're looking at a nursing home cost versus moving a loved one into your home, you'll make your money back in just one year. Then, every other month they stay with you is money back in the bank. That doesn't even include an improved quality of life and better health outcomes. 

Make Passive Income with a Rental Property

Adding an in-law suite to your property can significantly enhance its financial value by providing a source of additional income through long-term rentals. This extra income stream can help you offset mortgage costs or contribute to retirement savings. Making passive income from your in-law suite will require adhering to local regulations and zoning codes, such as requiring a parking space or size limitations. Do your research ahead of time to ensure your design doesn't hinder you from legally renting out your addition. 


Get the Added Space You Need in Your Home with a Team You Can Depend On

An in-law suite is a truly valuable investment for your property. Not only does it have the potential to increase the value of your property, but it's one of the few investments that allows you to make money almost instantly off of the renovation. Whether you rent it out or you move a loved one in, few renovation projects are able to compete with the return on investment.

At JMC Home Improvement Specialists, we're committed to spending time learning everything about your remodeling project from the start. Your intentions, design goals, future plans, and budget for the space are kept front and center throughout the entire process. Contact us to start the conversation about your in-law addition or any other remodeling needs in Northern New Jersey. 


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