ADU 101

What do guesthouses and granny flats have to do with the housing crisis in Atlanta?

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Illustration by Khoa Tran

In-law suites, granny flats, guesthouses, cottage houses, garage apartments—whatever you call them, accessory dwelling units could be part of the answer to the housing crisis in Atlanta. Here’s what you should know about ADUs. 

First, what is an ADU?

An accessory dwelling unit is a small home built on the same lot as a single-family residence. ADUs can be carved out of an existing building, like a converted basement or attic, or detached, like a freestanding tiny home in the backyard. Because ADUs are built on lots zoned for single-family dwellings, they add density to areas that previously had only one residential structure per lot. 

ADUs are relatively new to Atlanta. In his book, Red Hot City: Housing, Race, and Exclusion in Twenty-First-Century Atlanta, Georgia State University professor of urban studies Dan Immergluck says that nearly a decade ago, city officials recognized the need for more housing and hired consultants to assess the city’s zoning. As a result, in 2019, the city passed a zoning ordinance that increased—by nearly 40 percent—the area where detached ADUs were allowed.

What does this have to do with Atlanta’s housing shortage?

Housing must increase to accommodate population growth; when it doesn’t, cities see price increases and the kind of sprawl for which metro Atlanta is infamous. The solution? “We need to fit more housing on the amount of land we already have,” explains David Melton, business development manager at Atlanta ADU Co. One way to do that is to build more diverse types of housing: duplexes, triplexes, townhouses, small apartment buildings, and, of course, ADUs. Urban planners sometimes refer to this “gentle density” as “missing middle” housing. 

Why is it missing? 

Zoning regulations dictate how properties in a specific area can be used, whether for single-family homes, multifamily dwellings, or mixed-use developments, addressing things like building height, lot size, and density restrictions. The problem is that residential zoning in metro Atlanta is outdated, Melton says. About 60 percent of Atlanta is zoned for single-family homes. This means that housing types that tend to be smaller (and more affordable)—like ADUs, for example—are restricted in most of the city. This severely limits the number of people who can live in those areas. 

Learn more: How can I find out whether ADUs are allowed in my neighborhood?

It depends on where you live. The easiest way to find this information is to search online for the name of your city or county + GIS (which stands for Geographical Information System). If you live in the City of Atlanta, you can look up your address here; if you live in DeKalb County, you can look up your address here.

What can we do? 

Paul Donsky, senior communications manager at the Atlanta Regional Commission—which tracks building permits issued in the 11-county metropolitan area—agrees that more ADUs and other types of missing middle are needed. Still, he says, across the metro, more single-family building permits are issued than multi-family building permits. “We need the mix of the missing middle,” Donsky says. “No more just single-family and large apartments.” 

“We need the mix of the missing middle. No more just single-family and large apartments.” —Paul Donsky, senior communications manager at the Atlanta Regional Commission

The city needs housing that can accommodate populations that may not need or want (or be able to afford) traditional single-family homes. ADUs are a piece of that puzzle. “Not only [do ADUs] provide housing, but [they] provide more diverse housing: studio housing, one-bedroom–one-bathroom, two-bedrooms–two-bathrooms,” Melton says. “[ADUs] can serve a household of one or two.” 

Housing Authority of Dekalb County President and CEO E. P. “Pete” Walker Jr. believes that housing preferences are changing too. “People are getting used to having to share spaces where they live, where they work,” he says. “The group of young people that’s coming up right now aren’t as territorial about, okay, I gotta have a yard, and there is a different mindset out there now.”

Why do residents sometimes oppose zoning changes that would pave the way for more diverse housing types?

Residents in areas that start seeing greater density—via diverse and, often, more affordable housing types—sometimes fear a loss of property value, which can be concerning if someone’s largest investment is their home and if their financial future is tied to that residence. “I understand that fear as a homeowner myself—that one day my home wouldn’t be worth what I would hope it would be,” Melton says. “But I don’t believe adding density to a neighborhood devalues it.” 

A 2012 study in Urban Design International concluded that the value of single-family residential properties increased with density. Part of that property value increase was due to added amenities like sidewalks and a mix of retail, commercial, and residential surroundings. The study went further: Not only did properties increase in value, but the quality of neighborhoods—access to parks and other land uses—increased, too. 

“I think that all folks should have a say in what goes on in their neighborhoods and be able to kind of help design their neighborhoods,” says Molly Gunn, who has built ADUs on properties she owns in Chosewood Park, Peoplestown, and Benteen Park. “I also think that people should understand that Atlanta has housing trouble, and we need more density.” •