In 2021, Massachusetts Governor Charlie Baker signed legislation requiring that all communities served by the MBTA transportation system implement zoning districts that allow for the construction of multi-family housing by right. Called colloquially “MBTA Communities” after the legislation’s name, this policy has transformed the planning landscape in the eastern part of Massachusetts over the past three years. Communities have worked to implement the requirements of the state law, which require an average density of 15 units per acre and set target acreages for communities. The zoning changes are focused on the area around MBTA transportation hubs, to encourage more transit-oriented development.

MBTA stations and documented historic resources in the Massachusetts Cultural Resource Information System (MACRIS). Blue areas represent documented areas; red are National Register of Historic Places districts; and green are local historic districts. From MassMapper.

But the law has become controversial in many communities. While some have quickly adapted their zoning, others have made it clear that they are refusing to comply. At the time of writing, the Town of Milton and the Attorney General’s office have begun a court case to decide if the state can actually impose such zoning requirements on communities. And many communities have expressed concerns about increasing population and the issues that brings, such as more students in their school systems and traffic on the roads. Not to mention the potentially significant changes to the landscape, as many MBTA stations are located in historic downtowns.

What is often missing from the conversation, though, is that many Massachusetts communities have had low-density multi-family housing since the 19th century. Until the development of streetcars, and later cars, walking was the most common form of transportation in communities. There was no concept of spatial mismatch – where living, working, and service spaces are all in different locations. Everything had to be in one place and within easy reach. So communities naturally densified, providing more housing options near large places of employment such as mills, factories, and downtown cores, with services such as stores, schools, and churches located nearby.

This historic multi-family housing comes in a variety of forms, with a corresponding variety of architectural styles applied to them. Housing ranges from various configurations of two-family dwellings up to several-unit row houses. These house forms provided for multiple individual family units on one lot, providing a mid-level of density for a community that kept residents within walking distance of employment and services.

Small side-by-side duplexes near the Stanley Woolen Mills in Uxbridge

Of the two-families, perhaps the most common is the duplex: two units mirrored side-by-side, with paired entry doors centered on the building. The smallest form was often only one or one-and-a-half stories tall, with knee wall construction providing more livable space in the upper story. Many of these multi-family house forms were expanded at the rear by ells, additions that most commonly provided space for a kitchen.

Various other forms of two-family dwellings offered a bit more privacy and separation than the traditional side-by-side doors. Some two-families were constructed with the units back-to-back, with entry doors on separate side walls creating space between the units. Or, entry doors were moved to the outside of the façade.

In more urban areas, the two units of a two-family house were often stacked, one over the other with the same plan on each floor. These buildings may have one or two entry doors. Often only one door was used, to help the building better blend in to a neighborhood of single-family houses; the only tell that the building is a multi-family dwelling may be the repeated fenestration configuration on both floors or the presence of multiple mailboxes.

A line of classic triple-deckers in Worcester, where thousands of the housing form were built beginning in the late 19th century

And perhaps the most famous of Massachusetts’ multi-family housing forms is the triple-decker, or three-decker. With three flats stacked on top of each other, the long, rectangular footprint of the triple-decker provided an ideal form for long, narrow urban lots while giving families space and privacy. Urban areas throughout Massachusetts were filled with rows of triple-deckers into the early 20th century, when public safety laws ended their construction.

Many of these multi-family forms were often combined into larger forms. Two-families eventually became four-families, or even longer row houses. Triple-deckers were placed side-by-side, providing essentially a small six-unit apartment building. But these were often still done at a relatively small, human scale, and with common materials and styles, blending them in to a surrounding residential neighborhood of similar or smaller buildings.

As communities work to update their zoning and add more density, they should look to these historic multi-family neighborhoods in their own community. These early multi-family housing forms were found throughout Massachusetts, in communities large and small, urban and rural. What forms of gentle density already exist? Can these be encouraged and permitted, to densify the community in a way that is historically compatible? Not only will these multi-family forms provide additional housing opportunities, but they will also maintain the historic character of a community and the human-scale that many communities have long had, before cars and highways were introduced.