Missing Middle Housing Types

Issues Addressed:
Affordable Housing Housing Costs Housing Options Multigenerational Sustainable Housing
A diagram showing the front facades of housing types and given labels: small single-family, townhomes (attached single-family), cottage court (grouped small single-family), duplex, stacked duplex, triplex, stacked triplex, four-plex, six-pack, courtyard apartments.

What is it?

Missing middle housing types refer to a range of housing options that are smaller than conventional single-family homes, but are not large apartment buildings. They include various types of attached and detached housing units that are designed to be more affordable than conventional development. These units can include duplexes, triplexes, fourplexes, townhouses, and other types of small multifamily housing. Their relative affordability is driven by their “gentle density”—which lowers land cost per housing unit while not requiring the space, circulation areas, or infrastructure required of large apartment buildings—and their smaller square footages require less construction materials.

These housing types are called “missing middle” housing because they fill the gap between single-family homes and large apartment buildings in terms of density, and they can help address the shortage of affordable housing options in many areas.

Many communities have zoning codes and subdivision regulations that do not permit these housing types. Bans on missing middle housing types can be explicit in the codes or they can happen in effect through the combined application of dimensional standards, parking requirements, and subdivision rules. Allowing missing middle housing types includes aligning regulations so that it is truly enabled and encouraged.

How can it help?

  • Increased housing options: Missing middle housing types provide more housing options for people with different needs and budgets. This can help a community attract and retain a greater mix of residents, allow seniors to age in their community, and allow young people and new families to find homes.
  • Increased affordability: Because missing middle housing units are smaller, require less land per unit, and can have shared amenities and infrastructure, they can be more affordable than conventional single-family homes. This can help address the shortage of affordable housing in a community and make it more accessible to a wider range of people.
  • Improved walkability: missing middle housing types can make use of public sidewalk and trail infrastructure, making it easier for residents to walk to work, school, and run everyday errands. This can help reduce traffic congestion and improve air quality.
  • Preservation of open space: Construction of missing middle housing units can preserve open space and natural areas on the outskirts of a community that would otherwise be pressured by development.
  • Economic benefits: missing middle housing developments can bring economic benefits to a community and more concentrated demand for local businesses.
  • Sense of community: missing middle housing developments can foster a sense of community by bringing people together in a shared living environment.
  • Environmental benefits: Missing middle housing units can be designed to be more energy-efficient and environmentally sustainable, which can reduce energy needs, and greenhouse gas emissions.

Getting Started

  1. Recognize and promote the impact of missing middle housing types on common master plan goals, like increased housing options, increased affordability, open space preservation, and more. 
  2. If undertaking a master plan, include missing middle small housing types as a recommendation.
  3. Assess the existing built environment, existing parcel sizes and configurations, the community’s housing needs, local infrastructure capacity, recent real estate market trends, and property owner and developer interest in non-conventional residential development. Using these assessments, determine which missing middle housing types might be well-suited for different areas of your community.
  4. Audit your land use regulations to see what rules would need to be changed to allow (and encourage) missing middle housing development. This should begin with zoning use tables, dimensional regulations, parking regulations, and subdivision rules.
  5. Draft and adopt amendments to land use regulations that proactively support missing middle housing types. These amendments should be targeted toward promoting specific housing types that the community desires, given development constraints like actual lot sizes, rather than blanket increases to density.
  6. Promote missing middle housing types among property owners and developers active in your community or nearby.

Considerations

  • Not all housing types may be appropriate for every community, but there are many housing types and designs. Pursue whatever housing types that are most likely to be embraced by the community.
  • Many zoning codes include provisions for multifamily housing, but fail to distinguish between a three- or four-unit building and a hundred-unit building. Even if your community technically allows these missing middle housing types, untargeted rules will not promote their production.
  • Depending on the state of the real estate market, allowing more density could increase land values, translating to higher prices for existing homes, particularly in areas where the existing homes have low prices or are in poor condition. Price effects are less likely for properties that are unlikely to “flip” to higher densities.
  • In hot real estate markets, increasing allowed densities can contribute to displacement of established communities. Housing production incentives should be paired with restrictions to protect the vulnerable and avoid the social and public health consequences of displacement.
  • Consider form-based codes as a method of promoting missing middle housing types more directly, rather than through esoteric dimensional rules.
  • Consider Conservation Subdivisions and Village Plan Alternatives as means to allow these housing types.
  • Pre-approving housing types can reduce the guess-work by a town’s developers and zoning board when assessing potential developments.
  • Traditional neighborhood design included many types of housing nearby one another. This type of housing mix can reduce actual segregation by race, income, and other factors, and increase feelings of shared community.

Case Studies

  • Dover, NH
  • Hanover, NH
  • Grand Rapids, MI
  • Bend, OR
    • Read more

Resources

Related Tools

Three axonometric diagrams connected by one-way arrows. First, a small home on a small plot of land labeled "Historic, compact development pattern." Second, a larger home on a larger plot of land with arrows specifying setbacks, etc. labeled "Development mandated under zoning." Third and finally, a home and land parcel the same size as the first drawing, with arrows indicating setbacks, etc. and labeled "Reduced requirements."
Reduced Zoning and Subdivision Requirements
A subdivision of eight single-family homes surrounding a central green. The plot of land is labeled "Site plan that allows for community septic, prioritizing shared open space." Underground pipes lead from each home into a large underground box labeled "Joint septic tank." A pipe leads from that box into a smaller underground box labeled "Pre-treatment system." A pipe extends from that box and branches into many pipes with holes in them under a green area labeled "Community open space that doubles as a leach field."
Wastewater System Alternatives
A diagram of a single-family subdivision with twelve homes. Eight homes in red are labeled "Base Market-Rate Units." Two homes in yellow are labeled "Affordable Units." Two homes in blue are labeled "Bonus Market-Rate Units."
Inclusionary Zoning
A diagram with two versions of the same plot of land, one over the other. On the top version, the land contains only one single-family home with many wings and a large garage and a long driveway. This version is labeled with a large 'X' and "Regulations cannot mandate unaffordable housing everywhere." The version below contains two modestly sized single-family homes at the front of the site, and a driveway leading back to a cottage court, containing six small single-family homes around a central green. This version is labeled with a large checkmark and "Workforce housing must be allowed in a majority of residential areas."
Workforce Housing Ordinance
A diagram of a parcel of land. On the top is a mix of one- to three-story buildings, many with an apparent mix of uses, sitting along the intersection of two roads. This is labeled "Mix of uses using traditional village design." Lines at the edges of this area point draw down, showing this area is at the center of a larger area shown in dark green and apparently undeveloped. It is labeled "80% of rural and conserved in VPA."
Village Plan Alternative (VPA)
A grayscale diagram of a three-story, mixed-use, traditionally styled building with three columns of windows and a cornice. On the left is a diagram of the front facade, on the right is an axonometric diagram of the building on its land parcel. There are unlabeled arrows implying measurements for total height, total living area height, ground floor height, upper floor heights, cornice heights, ground and upper floor fenestration, setbacks, land widths, parcel depths, etc.
Form-Based Codes
A diagram of an idealized age-friendly neighborhood. The neighborhood includes a mix of housing types, including detached single-family homes of various sizes, mixed-use buildings, and a cottage court. The diagram includes the following labels pointing to aspects of the drawing: "Nearby retail, community center, and open space;" "Diverse housing options, including apartments and starter homes;" "Single-story housing layouts with shared amenities;" "Sidewalks and other accessible infrastructure;" and "Accessory dwelling units for multi-generational households."
Age Friendly Neighborhoods