Apartment buildings that offer between two and nine units offer the lowest prices available to U.S. renters, but the country keeps trending toward single-family homes and high-rise apartment buildings, resulting in a “vanishing middle” of smaller units that doesn’t bode well for the future.

So surmised Bloomberg in a recent report, arguing that there are good reasons to revive the numbers of smaller-unit apartment buildings because, in addition to providing cheaper rent, they “add density without compromising the character of quiet, single-family districts.” They also provide “a convenient way for older homeowners to downsize without leaving their neighborhoods,” Bloomberg said.

Bloomberg used research from Enterprise Community Partners, an affordable housing nonprofit, and the University of Southern California in reporting that buildings with two to nine rentals offered the cheapest rents.

Also using data from the U.S. Census Bureau, Bloomberg added that the number of small- to medium-sized housing units, defined by the Census Bureau as between two and 49 apartments, accounted for a quarter of new complexes built in the United States in the 1970s and ’80s. However, since 1990, the rate for those numbers of units built has dipped to 15 percent of the nation’s new housing stock.

One culprit in the falling numbers are zoning rules that seem to favor single-family construction, making it harder to win approval for larger projects, Bloomberg said. It also faulted regulatory costs that accompany multifamily housing, because when developers go through all the trouble to win approvals for such housing and those rules, they want to build more than just a few apartments.

Rewriting zoning codes would be a good start to winning back numbers for the “vanishing middle,” said Andrew Jakabovics, vice president for policy development at Enterprise Community Partners and an author of its research paper. He said:

We need to build stuff today that’s affordable today. We also need to future-proof ourselves by building stuff today that will be affordable 10 or 20 years from now.

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