Quoted from National Association of REALTORS® Growth Management Fact Book (2022 Update).
“The American Planning Association report ‘The Rules That Shape Urban Form; points out three ways in which form-base codes can be a good tool for addressing housing affordability.
- By requiring that buildings of a certain size and shape be built in specific transect zones, form-based controls can make it more likely that attached or multifamily homes are built in zones where they are permitted.
- The form-based principles of focusing less on permitted use controls should allow building use to change from nonresidential to residential over time—for example, from office building or warehouse to lofts, condos, or apartments—which could help meet the nation’s shortage of multifamily units.
- Form-based tools could allow more units to be built within a specific building form. More units in a given envelope mean smaller units and more units to bear the land costs, which may make them more affordable.
On the other hand, the report also notes that there are four ways in which form-based codes may not promote housing affordability.
- Form-based codes may restrict or eliminate density or height bonuses, a tool that communities often use to encourage affordable housing construction.
- Form-based codes may inhibit affordability by requiring vertical mixed use buildings (i.e., housing over a retail or commercial ground floor), which may be more expensive to build.
- Because they better reflect the built environment, form-based codes may reduce opportunities for affordable housing by eliminating “overzoning” (i.e., zoning regulations that permit residential buildings of three or more stories but are developed with one- and two-story single-family homes.)
- Form-based controls often include architectural standards for new development and redevelopment that can indirectly raise the cost of housing constructed under the code.
Since one of the promises of a form-based code is to achieve a ‘fine grain’ of mixed use, including multiple housing types, it may be possible for the code to create a market environment in which affordable housing can be achieved. This outcome would be especially true where a form-based code explicitly establishes different housing types in a redevelopment area where no residential development presently exists. To date, most developments that have proceeded under form-based codes have tended to be above average cost for the region. However, a 2021 study by the Form-based Codes Institute and Smart Growth America found that the average rent for municipality development in places with form-based codes grew at a slower pace than comparison areas with conventional zoning. This study determined that this was because there were more housing options in the studied form-based code areas serving a wider range of household incomes.”
