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What Types of Floor Plans Can an ADU Have?

With a custom ADU, you can choose the right floor plan, square footage, and special features for your needs and property size. Discover your dream home today.

January 1, 2020

While you may think that all ADUs are the same, that is definitely not the case. In fact, there are a variety of different floor plans and features to choose from. Determining all of these factors on your own can be overwhelming and confusing, which is why it’s a great idea to work with a custom, start-to-finish ADU company like Cottage.

What Is an ADU?

An ADU, or an accessory dwelling unit, is a separate and livable structure that is built on the same property as a main dwelling unit. While ADUs can come in many different variations, the most common is a backyard cottage that is separated from the main, single-family home.

Depending on the existing structure and lot, an ADU can either be constructed from scratch, converted from an existing structure like a garage or basement, or built on to be attached to the main structure.

Even though ADUs may look different depending on the type, they all require their own foundation, utility connections, and living areas. Additionally, ADUs require a separate bathroom and kitchen area in order to be considered a separate and liveable space. While ADUs exist everywhere, these units are particularly popular in California as a result of high property prices and rents in large metropolitan areas such as Los Angeles and San Francisco.

What Are the Uses of ADUs?

In order to choose the best floor plan for your ADU, you first need to consider what you’re using it for. There are several different uses for ADUs to consider, whether it’s to house adult children, aging parents, or to earn additional rental income.

Adult Children

One common use of ADUs is to house adult children. With extremely high rents and a crazy housing market in many parts of California, it can be difficult for younger adults to afford their own places. Rather than fit the trope of a Millennial living in their parents’ basement, you can provide your children with a mature and private space of their own with an ADU.

Aging Parents

Another great use for ADUs is to house aging parents. With age, many older adults are no longer able to take care of themselves. While this process can be challenging, assisted living facilities and nursing homes aren’t the only answers.

Instead of keeping your parents away from family in a different environment, you can keep them close by while still providing them with the space they need to feel independent and comfortable in an ADU.

Rental Income

The third most common use case for ADUs is to earn additional income by renting out the unit. In this case, you should look at an ADU as an investment that allows you to earn back your money and then some by charging rent to create a self-sustaining source of income.

This option is particularly beneficial in the hot rental markets of Southern and Northern California as it provides tenants with a better alternative to high rise, jam-packed, and corporate-managed apartment complexes. In addition, having the additional option for rental income has proved to be attractive for property investors, which adds to the potential sale price of your home down the road.

What Types of Floor Plans Can an ADU Have?

Once you have determined the purpose of your ADU, you can move on to choosing the right floor plan. There’s no shortage of floor plans to choose from for your ADU, and the sheer amount of options can quickly become overwhelming. Here’s a breakdown of five basic ADU floor plans to consider for your property:

Studio Tiny Home

If you’re considering an ADU to comfortably house the occasional guest, then you may want to consider a studio tiny home. This is also a great option to choose if you don’t have a lot of room to work with or have a smaller budget. These units do not have a separate bedroom space and instead have an all-in-one layout that features a sleeping area, living area, dining area, and a small kitchen. Studio tiny homes can range in size from around 250 to 500 square feet.

One Bedroom, One Bathroom

If you’re looking for a floor plan that feels more like a legitimate apartment rather than an ADU, then you may want to consider a one-bedroom, one-bathroom floor plan. This floor plan is a great way to provide affordable yet private housing for an aging parent or an adult child. These units usually range from 350 to 700 square feet and have a bedroom that is separate from the rest of the living space—complete with a dining area and a kitchen.

Two Bedroom, One Bathroom

On the other hand, if you’re looking for more space to house your aging in-laws or a married child, then you may want to consider a larger two-bedroom, one-bathroom floor plan. This floor plan provides plenty of space for more than one person to comfortably cook, eat, sleep, and relax. These units usually range from 600 to over 1,000 square feet.

Two Bedroom, Two Bathroom

If one bathroom isn’t enough, you can add another within a two-bedroom, two-bathroom ADU. This floor plan is ideal for housing two or more people that may require some extra space so that no one is left fighting for the shower or sink in the morning. These units usually range from 750 to 1,200 square feet depending on the city or county requirements.


If you’re interested in building an ADU to earn some extra rental income and have a property that qualifies for multiple ADU units, then you may want to consider a duplex floor plan. A duplex floor plan provides you with two units that you can rent out separately. A shared wall separates these two units and helps you cut down on construction costs.

Depending on the space you have available, you could even go with a two-bedroom duplex layout for a total of four bedrooms that would comfortably maximize the return on your investment.

How To Choose the Right ADU Floor Plan and Builder for You

If you’re still unsure of which ADU floor plan to choose, consider reaching out to the experts at a custom ADU company like Cottage. Cottage can then help you create the perfect ADU floor plan to meet all of your needs. Cottage is by your side from the very beginning: from helping to get the right paperwork and permits filed all the way through construction and design. With our network of licensed and thoroughly vetted contractors, you are sure that the space you’re building is built to last.

So before you try to construct an ADU all on your own or turn to more restrictive options such as prefab ADU providers, reach out to the experts at Cottage for a free consultation and estimate for the space of your dreams.

Floor Plans To Love and Live in

There are many different ADU floor plans to choose from, ranging from tiny studios to spacious two bedrooms. The right floor plan for your ADU will depend on what you’re using it for—whether it be an aging parent, an adult child, or for rental income.

In any case, building an ADU is extremely beneficial and can help you boost your property value while also earning extra income.