Thomas Barrie is professor of architecture at NC State University.

Thomas Barrie

Outdated zoning codes that have dominated American land use planning since the 20th century are changing. Cities and states across the United States are breaking the stranglehold of the single-family house and reviving once-common missing middle housing. Zoning reform is part of comprehensive strategies required to solve 21st-century development and housing challenges. It is an effective way to address a full spectrum of issues that many consider important—climate change, affordable housing, spatial justice, growth impacts, and health and well-being—and create sustainable, affordable, equitable, and healthy communities.

Missing middle housing is diverse housing—it provides choices between single-family houses and large apartment buildings. Duplexes, triplexes, quads, town houses, multiplexes, cottage courts, live-work-and-shop houses, and accessory dwelling units serve diverse housing preferences, ages, household sizes, and income levels. 

Zoning reform that supports housing diversity is essential to address the dominant role the built environment plays in the global climate emergency. The majority of buildings in the United States are inefficient single-family houses. Smaller units with shared party walls use fewer materials and require less energy to heat and cool. Compact urbanism mitigates sprawl and the environmental impacts of autocentric development and supports multimodal transportation. 

Missing middle housing is also one piece of the affordable housing puzzle. After decades of diminishing federal support of affordable housing and economically stratified development patterns, the housing market and zoning reforms are among the few effective tools cities have to solve the housing crisis. Missing middle housing provides smaller, affordable choices and ownership and equity options. Compact housing reduces energy and maintenance costs, and compact urbanism transportation costs. 

Some worry that opening the market will result in gentrification. Growing cities will experience gentrification, especially where zoning has produced economically stratified settlement patterns. In supply-and-demand housing economies single-family, large-lot zoning inflates prices in high-wealth areas making low-wealth communities soft markets for development. In states with weak housing laws there is no guarantee that the new housing will be affordable. However, recent research studies establish that over time housing diversity can open a broader range of housing price points. 

The legacy of zoning laws used to enforce racial segregation, and endemic economic segregation, have spurred zoning reform in many cities and states. There is growing consensus that large-lot, single-family zoning erects economic barriers that prevent lower-income people from accessing the schools, employment, and services of higher-wealth areas. In low-wealth communities inadequate transportation modalities limit access to jobs, schools, and services; economic isolation results in scarce or inflated goods and services. 

Smart cities guide market-driven growth and regulate the visual character of the built environment. The smaller units of missing middle housing, refined by form-based codes, are more compatible with older residential communities than large single-family houses or multifamily apartments. Social stability and diversity are supported by housing choices that allow people to age in place and trade down or up without moving out. Compact urbanism supports local businesses, and small-scale housing opens the market to local housing developers. 

Research has established that walkable communities that provide multimodal transit choices are also healthier environments. People exercise more, and emotional and mental health is supported by social places—sidewalks, local businesses, and other settings for impromptu meetings. Conversely, auto-dependent exurban housing that requires daily commutes and multiple shopping trips has many negative physical and mental health impacts.

Opponents of zoning reform span the political spectrum, enshrine single-family zoning, and cite fears of a loss of character and control of their communities. Often the loudest voices have the least to lose in a changing world—they live in affluent neighborhoods and can mount well-funded opposition. The fiercest battles are often in areas of single-family houses on large lots close to city centers, services, and public transportation. 

We should make missing middle housing easier to build. City-wide, comprehensive zoning reform can mitigate gentrification. It can also expand housing diversity and transit-supportive communities. It is also simply the right thing to do—everyone needs to do their fair share to build a sustainable, equitable, and healthy future.

No one likes to be told they can’t continue to live the way they have—but our times require change. Cities that don’t adapt will wither, victims of the changing climate, social trends, and economic systems.

Ultimately, we must build for future generations and the common good.

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