Missing Middle Housing and the Affordability Crisis

Walk through any pre-war American neighborhood and you will find it: the duplex on the corner, the four-unit apartment building mid-block, the courtyard complex with six units arranged around a shared garden, the carriage house converted to a rental behind the main house. This is the missing middle — the range of housing types that sit between the detached single-family house and the large apartment building, and that once formed the backbone of American urban neighborhoods.

It is called "missing" because it largely disappeared from new construction after World War II, and because its absence is felt most acutely in the middle of the housing market — the households that earn too much for subsidized housing but too little for the market-rate single-family homes that dominate new construction.

How It Disappeared

The disappearance of missing middle housing is not a mystery. It was the direct result of zoning policy. As single-family zoning spread across American cities and suburbs in the mid-twentieth century, the duplex, the triplex, and the small apartment building were effectively banned from most residential land. The areas where they already existed were grandfathered in — which is why pre-war neighborhoods often have more housing diversity than post-war ones — but new construction of these types was prohibited on most residential land.

The consequences were predictable. As demand for housing grew and the supply of missing middle types stagnated, prices rose. The housing market bifurcated: on one end, expensive single-family homes on large lots; on the other, large apartment complexes that required significant capital and generated significant opposition. The middle — the gentle density that had once made neighborhoods affordable and walkable — was gone.

What Missing Middle Housing Does

Missing middle housing types share several characteristics that make them valuable at the neighborhood scale. They are small enough to be built by small developers and individual homeowners, which means they can be distributed throughout a neighborhood rather than concentrated in large projects. They are compatible in scale with single-family neighborhoods — a well-designed duplex is often indistinguishable from a large house. And they generate the density needed to support walkable retail, transit, and civic uses without requiring the kind of large-scale redevelopment that displaces existing residents.

They also provide housing for the people who make neighborhoods function: the teachers, nurses, firefighters, and service workers who cannot afford single-family homes in the communities where they work. The affordability of missing middle housing is not primarily a function of subsidy — it is a function of size. A 700-square-foot apartment in a well-located duplex is affordable because it is small, not because it has been subsidized.

The Reform Landscape

The policy landscape is changing. The zoning reform movement that has gained momentum over the past decade has focused heavily on missing middle housing — allowing duplexes and triplexes by right in single-family zones, reducing minimum lot sizes and setback requirements, eliminating parking minimums that make small infill projects financially unviable.

These reforms are necessary but not sufficient. Zoning that allows missing middle housing does not guarantee that it will be built. Construction costs, financing structures, and neighborhood opposition all shape what actually gets built. The most effective interventions combine zoning reform with streamlined permitting, pre-approved design templates, and financing tools that make small-scale infill development financially viable for small builders.

Design Quality Matters

One of the most persistent objections to missing middle housing is aesthetic: that duplexes and small apartment buildings will look out of place in single-family neighborhoods, that they will lower property values, that they will change the character of the street. These objections are not always wrong — poorly designed infill can be genuinely harmful to the public realm.

But the solution is not to prohibit density — it is to require quality. A duplex that is designed to look like a large house, with a front porch, a pitched roof, and windows that relate to the street, can be a genuine asset to a neighborhood. A four-unit building that wraps its parking in the rear, activates the sidewalk with stoops and entries, and uses materials consistent with the neighborhood character can be indistinguishable from the pre-war buildings that everyone agrees are worth preserving.

The Small Town Dimension

In the small cities and towns of the Driftless Region, the missing middle housing crisis takes a particular form. These communities often have aging housing stock, limited new construction, and a growing mismatch between the large family homes that dominate the market and the smaller households — young adults, empty nesters, seniors — who need something different.

The opportunity is real. Many Driftless communities have historic main streets and residential neighborhoods that were built on missing middle principles — and that could absorb gentle infill without losing their character. The challenge is regulatory: zoning codes written in the 1970s and 1980s that prohibit the very building types that made these communities work in the first place.

Updating those codes is not a radical act. It is a return to the common sense that built the neighborhoods we most admire.