Missing Middle Housing — What It Is, Where It Went

(1) A Missing Middle-style apartment building (right) stands next to, and is just a smidge taller than, a single-family home. (2) In this site plan, five cottage-style houses (of about 650 square feet each) fit on a 14,976-square-foot (or .34-acre) lot. (3) From a distance, this four-unit house looks like a single-family residence. (4) Clues that it’s not: the multiple front doors and mailboxes. (5) This Tudor-style home looks like a mansion but it contains five townhouse-like units.

(1) A Missing Middle-style apartment building (right) stands next to a single-family home. (2) Five cottage-style, 650-square-foot houses fit on a .34-acre lot. (3 and 4) From a distance, this four-unit house appears to be a single-family residence. Clues it’s not: the multiple front doors and mailboxes. (5) This Tudor-style home looks like a mansion but it contains five townhouse-like units.

Illustration by Opticos Design | Photographs by Melissa Stanton

There’s a mismatch between the housing that’s available and what communities need.

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Screenshot of the Missing Middle Housing fact-sheet

Download and share the handout Missing Middle Housing — What It Is, Where It Went, a one-page PDF adapted from Discovering and Developing Missing Middle Housing, a free publication by AARP.

Learn More: AARP.org/MissingMiddleHousing

Missing Middle Housing (the term was coined by architect and urban designer Daniel Parolek of Opticos Design) describes a set of residential building types that exist in the middle of the continuum between detached single-family houses and large apartment buildings.

Such midsized, often moderately priced homes placed in walkable locations are referred to as “missing” because very few have been built in the United States since the early 1940s.

Since Missing Middle dwellings are house-scale, the design and size of the multiunit buildings fit comfortably among detached single family houses. The styles include the following types:

Single-unit, COTTAGE COURT houses (shown at right) are typically 1 to 1½ stories tall and are oriented around a courtyard that serves as an outdoor community space in lieu of rear yards.

A DUPLEX residence consists of two units within a building that is of similar size and scale to a single-family house. One unit is stacked atop the other. In either case, the entries to both units face the street.

A classic FOURPLEX consists of two side-by-side units on the ground floor, with two more units stacked directly above. At two stories in height and 40 to 50 feet in width, a fourplex’s dimensions are comparable to those of many single-family homes.

A MANSION APARTMENT maintains the form and scale of a large estate house, while accommodating multiple units. In locations with historic mansions or large manor houses (such as the Tudor-style residence at right), it can be very easy to adapt existing, oversized single-family houses or create new multiunit buildings that will seamlessly blend within the context of the street or neighborhood.

TOWNHOUSES are connected to adjacent buildings on one or two sides via shared walls. Each has an entry that faces a street or courtyard. The homes typically include a small rear yard. Because of their small footprints and shared walls, townhouses make efficient use of land, which means they can be constructed and sold at a lower price than a new, detached house. Since townhouses are not stacked, it alleviates concerns about noise from upstairs neighbors.

A LIVE/WORK BUILDING combines a dwelling unit, usually located upstairs, with a ground-floor space that can accommodate a range of nonresidential uses.