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Accessory Dwelling Units Allow Homeowners to Choose Where They Age

Mobility friendly and energy efficient, ADUs offer more options for aging in place

The Whitley’s at home in Santa Cruz. Carrie and his wife recently added an ADU unit to the back of their home in order for their daughter Brenda to reside there.
Gabriela Hasbun

Remember “mother-in-law suites” or “granny flats"? Those tiny housing units often located behind a suburban home proliferated in post-World War II America until zoning laws shut down their construction. Today they are experiencing a bit of a renaissance in U.S. communities — with real benefits to older Americans.

The contemporary term for a second, smaller home built on a parcel usually zoned for a detached house is accessory dwelling unit (ADU). To create affordable housing and slow sprawl, some cities and states have passed laws to remove restrictions that hindered such development. In 2017, California made ADUs legal in cities throughout the state, and more recently the state has streamlined fees and the building approval process. From January 2017 to June 2019, Los Angeles issued nearly 12,000 ADU building permits.

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This is a potential boon for people who hope to remain in their homes as they age, says Dana Cuff, a professor of architecture and director of the think tank CityLab at UCLA, and one of the writers of the 2017 California ADU legislation. “As people age, and they want a different living arrangement, they can stay in their communities,” Cuff says, rather than facing the stress and dislocation of moving to a new neighborhood.

ADUs allow people to age in place by providing an array of options, such as an easy downsize to a separate, more accessible home on the property. The main house can be rented or a grown child can live there (with his or her family). Other options are to use the ADU as living quarters for a caregiver or for a relative who requires care. Or the homeowner may be able to rent the ADU for retirement income (also defraying the cost of construction, which can be as low as about $40,000 or reach into the hundreds of thousands).

"An ADU allows people to keep their connections to the community,” says Alan DeLaTorre, the Age-Friendly Program manager in Portland, Oregon's Bureau of Planning and Sustainability, which promotes aging in place. In addition, older Americans often live in homes that were designed without mobility considerations. Many have multiple levels, and most are built up from street level. Those barriers can push older people out of their homes before they are ready to move, DeLaTorre says. But ADUs, which can be built with mobility in mind, allow them to stay. Modern construction is also more efficient, keeping heating and cooling costs lower. A 2018 AARP survey found that 67 percent of adults would consider living in an ADU to be close to someone but still have a separate space. One-third of the respondents said that they would consider building an ADU.

The interior of Walt Drake's ADU at his son Scott's home
Frederik Brauer

A New Home for Dad

When Walt Drake decided to downsize in 2013, he sold his house in Decatur, Georgia, to his son Scott. But Walt, a 75-year-old practicing attorney, couldn't find a condo he liked. So Scott, 44, built a detached 800-square-foot ADU for his dad.

"It has worked out great,” Scott says. “It's very private. I can go a few days without seeing him, or I can see him five times a day if I want to."

The ADU was built on ground level to eliminate steps. Walt is in good health, but his son says having the ADU has made it simple to check on Walt when he has had medical issues. The arrangement has also allowed Scott's two daughters “a whole new level of interaction with their grandfather."

Scott said it cost around $350,000 to build. Several friends, after seeing the ADU, are planning to build one as well. “We got kind of lucky,” Scott says. “This worked out as a perfect solution."

Free Resources

Interested in an ADU? AARP has free resources, including a design catalog, technical drawings, resources about financing and budgeting, and a video library.

Visit aarp.org/adu and 
aarp.org/futureofhousing

Types of ADUs

• Detached backyard cottage

• Attached addition to existing home, with separate entrance and kitchen

• Interior (upper level) attic apartment

• Interior (lower level) basement apartment

• Above-garage addition that serves as an apartment over the garage

• Garage conversion; an attached or detached garage made into an apartment

“People love their communities and neighborhoods,” says Shannon Guzman, senior strategic policy adviser at AARP. “Moving to a more affordable location can take them away from the people and places that enrich their lives. We have to rethink housing and find better solutions, like ADUs.”

Rules and Regulations

ADUs were somewhat common before the suburban development boom (think of an apartment above a detached garage). But the postwar rise of single-family housing on individual lots became codified in strict zoning regulations. In recent years, more communities have allowed ADUs on residential lots, as long as they adhere to local size and lot placement limits.

Some states, such as New Hampshire, Vermont, Oregon and Washington, have passed laws requiring most or all cities and counties to allow ADUs, with some restrictions. Check with your local office in charge of land use and permitting. Ask what regulations apply, what permits are needed and what fees you will have to pay.

Some communities apply the same regulations to ADUs as they would other homes. But some local governments apply additional rules to ADUs. Some limit short-term rentals through services such as Airbnb. Some communities will allow rentals only if the owner lives on site; in other words, you can't rent out both your main home and the ADU. Some cities go even further, requiring that an ADU not be rented at all and must be used by a family member or caregiver.

A Daughter Nearby

In 2017, Carrie and Sterling Whitley found that maintaining their house in Santa Cruz, California, was becoming a challenge. But the Whitleys, who are in their 80s, had owned the house since 1971 and didn't want to move.

Sterling and Carrie Whitley in front of their Santa Cruz CA home
Gabriela Hasbun

So instead, they moved their daughter in. Brenda Whitley, 60, now lives in a 500-square-foot addition that cost $158,000 to build. The family got some help from a program called My House My Home, a partnership between Habitat for Humanity Monterey Bay, the city and county governments, and Senior Network Services. And they did some of the construction work themselves.

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On Sundays, Brenda takes her father to his religious meetings. She helps with the yard work and keeps an eye on their health. The decision to move in wasn't a difficult one and it has saved money for Brenda and her parents, she says. “I figured I could continue paying my mortgage, or I could pay into something that will help my parents out."

With the arrangement working well for all of them, Brenda says the plan is to continue for some time.

"That's our dream,” Brenda says. “I don't want them to go into assisted living. This way, they would be able to stay at home. I could check on them every day. I feel very lucky."