​
​

​missing middle housing

Source: Opticos Design

The Missing Middle refers to a range of housing types that, in density and intensity, lies between the traditional single-family detached home and the multiple-unit apartment complexes. That is, they represent the housing typologies in between that range, which have been disappearing from cities. This range includes the subdivision of existing structures like town homes and lofts, duplexes and fourplexes, and smaller apartment or condominium buildings or courts. In other words, Missing Middle Housing offers greater choice in housing types that still blend into existing single family neighborhoods, unlike mid-rise apartment buildings. They are typically more affordable than a single-family home because they are smaller and share communal parking and lawns. These building types typically have a residential unit density in the range of 16 to 30 units per acre but are often perceived as being less dense because they are smaller in scale.

This is the type of housing that fell out of fashion after World War II, when young families and others fled cities for the houses, driveways and ample yards of the suburbs. But now, these typologies can be helpful to leverage new needs of the market: Singles, childless couples, and empty nesters, who are seeking the benefits of dense urban environments. According to the National Association of Realtors, walkability is fast becoming one of the most important factors in choosing where to live. People want of all ages want easy access to amenities such as stores, businesses, cultural center, and transit.

Missing Middle Housing cannot be effectively regulated by conventional, land-use and density-based zoning because these building types often have medium to high densities, excluding them from the singly-family use zone, but their small footprints with lower heights don’t meet the requirements of multifamily use zones. As a solution, many policy recommendations to increase the availability of these missing middle housing options include adopting Form-Based Coding. This type of code is a land development regulation that fosters predictable built results and a high-quality public realm by using physical form (rather than separation of uses) as the organizing principle for the code. It creates a range of housing types appropriate for the community at large and is created based on the community’s existing physical patterns, climate, and other considerations.

​While this range of housing lies conceptually “in the middle” between pure single-family and more typical multi-family, it also can occupy the physical space between single-family neighborhoods and commercial corridors, allowing for a gradual transition in increasing density. This is an important tool as Pittsburgh turns more and more to infill development to accommodate the city’s growing population. Some examples of the "missing middle" housing options include:

Duplex (side-by-side)
A small- to medium-sized structure that consists of two dwelling units, one next to the other, both of which face and are entered from the street.

Duplex (Stacked)
A small- to medium-sized structure of two stacked dwelling units, one on top of the other, both which face and are entered from the street.

Fourplex
This building type is a type of medium structure that consists of four units: typically two on the ground floor and two above with a shared entry.

Carriage House
Also known as an Accessory Dwelling Unit, this building type is a small residential unit that is located at the rear of a lot and has been renovated from garage usually.

Bungalow Court
This building type consists of a series of small, detached buildings of multiple units that are arranged to define a private rear yard and community space.

Townhouse
This small- to medium-sized structure consists of two to eight (usually) attached single-family homes placed side by side and therefore sharing and interior wall.

Further Reading

Next City | "Will U.S. Cities Design Their Way Out of the Affordable Housing Crisis?"

Congress for New Urbanism | Missing Middle Housing

Urban Land Institute | The Missing Middle: Affordable Housing for Middle Income Families in the City of Austin