A new book argues that the U.S. is about to see more accessory dwelling units and guides homeowners on how to design and build them.
There’s a lot of single-family zoning in the center of our cities, and urban planners, civil society, and city leaders are questioning whether these zoning rules make sense. We’re missing dwellings that can house more people and are more affordable, such as duplexes, triplexes, and ADUs.
I don’t think tiny houses on wheels will soon become a widespread form of housing, because they aren’t yet permittable. But media coverage of them has helped to spur more interest in small housing in general. These factors are positioning ADUs to become a popular movement.
Where are ADUs already taking off in the U.S.?
A city must relax their ADU codes to increase their number. In 2017, the state of California did just that. While the legislation did not address one the most problematic issues, the owner occupancy requirement, it did relax the rules on providing parking spaces for ADUs. Los Angeles’s code already didn’t require owner occupancy, so the statewide reduction in other regulations has been especially effective there. L.A. went from having 142 ADU permits issued in 2016 to roughly 2,000 in 2017.
San Francisco, Oakland, Santa Barbara, and numerous other California cities have also experienced a significant uptick, though not as extreme as L.A.; Portland and Austin, Texas, are other fairly ADU-friendly cities. Though this is a pretty limited subset of cities, the interest and demand for ADUs is growing.
The other argument worth noting is that cities in which ADUs aren’t legal still have many of them; people are just building them illegally. When a city relaxes ADU codes, it encourages people to construct more of them—and build them better so they’re safer.
What should one keep in mind when designing an ADU?
Given the small size of an ADU, it’s necessary to have a “great room” that houses the living room, dining room, and kitchen in a contiguous space. Such a room with high ceilings and a visual connection to an outdoor area that’s adjacent to the ADU makes the space feel bigger than it is.
Also, ADUs are a form of urban infill housing, so it’s a best practice to be respectful of neighbors and not infringe on their privacy. This means being careful in terms of placement of doors and windows.
One critique of ADUs is that they encourage more short-term rentals, which actually exacerbate the dearth of affordable housing. What’s your response?