• A zoning research project for the National Association of Home Builders

Missing Middle Housing Form-Based Coding Strategic Advising/Implementation Citywide/Regional Plans Social & Environmental Justice

NAHB Report: Diversifying Housing Options

Opticos Design worked with the National Association of Home Builders (NAHB) to complete the research for a report, “Diversifying Housing Options with Smaller Lots and Smaller Homes.

NAHB recently retained Opticos Design Inc., the firm that coined the term “Missing Middle Housing,” to identify ordinances and codes across the United States that enable the construction of a greater mix of housing types and smaller, more affordable homes. More than 100 codes and ordinances from a variety of communities and cities were evaluated across four categories: accessory dwelling unit (ADU) ordinances, small lot ordinances, cottage court ordinances, and form-based codes (infill and greenfield). 

Examples from across the country were selected and featured in the report. Out of these, ADU ordinances, or those aimed at creating a secondary dwelling unit on the same lot as a main housing unit, were found to have the most significant effectiveness in enabling a greater, more affordable housing mix.

Key Findings

Awareness is increasing that multifamily development can be done effectively through infill housing approaches. More communities are revising their codes to encourage smaller homes and unit types, which the market has responded to favorably. It is important to note, however, that the projects that have received the most positive recognition and community support of code changes are those where the team has shown a commitment to aspects such as good design and communicating intent, rather than just affordability. 

A key conclusion of NAHB’s overall research on state and local housing affordability approaches is that both a greater supply of housing and a greater diversity of housing types are required. The dichotomy between single-family detached homes and the large multifamily buildings often invokes a NIMBY reaction. Building a greater mix of housing in a way that discreetly adds density to communities as outlined in this report may be a beneficial path forward.

Paraphrased from Key Research Findings and Influential Factors (p. 7)

This report shines a light on how state and local policy changes and good design can address this Missing Middle in housing today.

— Debra Bassert, AVP, Land Use & Design, National Association of Home Builders