How Single-Stair Reform Can Help Unlock Incremental Housing
Oak Terrace, a small apartment building in Somerville, Massachusetts.
The design of older multifamily and apartment buildings always fascinates me — the ways in which we've historically been able to create places for people to live in cities in both edifying and productive ways.
One such structure stands out to me, both as a reminder of the great multifamily housing we’ve been able to make in this country and as a promising model for the future.
It’s a small apartment building that overlooks the intersection of Elm Street and Somerville Avenue. The building is three stories tall, covered in a beige stucco, and laid out like an upside-down U curling around a small courtyard. A pear tree stands guard at the entrance, next to shrubby holly and inkberry bushes. A small sign reads, "Oak Terrace."
Oak Terrace stands out because its genus is now exceedingly rare. It does have its relatives, but this type of cloistered courtyard structure is quite hard to build today.
One key reason is that our codes are deeply out of sync with the buildings that we have and the buildings that we need. In the 95 years since Oak Terrace was built, we have determined through our zoning, building and fire codes that these types of small apartment buildings are dangerous, and that they detract from neighborhoods. Building more of them is effectively illegal.
A recent report from Harvard’s Joint Center For Housing Studies called out a chief culprit: There is a requirement in our national building code (confusingly named the International Building Code, or IBC) that calls for most new apartment buildings to have “two stairs connected by a smoke-proof and fire-rated corridor.”
Developers — like all humans — are utility-maximizing creatures. If they must put in two means of egress with an unbroken corridor in between them, then they will design a very long hallway with rooms on either side, reminiscent of most modern hotels. Instead of the old skinny and narrow structures, new apartment buildings have become long and wide. They take up a lot of land, require a lot of capital, and, in my humble opinion, are not particularly interesting to look at.
Oak Terrace, with a single stair serving half of the building, doesn’t quite fit in with these exacting corridor and egress requirements. And so, even if we were to wave a magic wand and eliminate parking requirements and dimensional and density regulations, this one rule in the IBC would prevent its construction. As the Harvard study points out, this requirement has significantly contributed to the dearth of small and midsize urban infill both here where I live in Massachusetts and across the country.
Fire deaths per capita in the United States remain quite high, regardless of our single-stair exit limits. (Source: Joint Center for Housing Studies.)
While we are quite strict with our stair requirements, we still rank rather highly in terms of fire deaths per capita (the report indicates that fire sprinklers are much more likely to be the culprit than stairs, with 99% of home fire deaths happening in homes without sprinklers). It’s safe to say that the number of staircases in a structure might not be the key variable.
In fact, many other countries with significantly lower fire deaths per capita, such as Spain, France, New Zealand, Switzerland, Great Britain and Germany, do not have this rule. Even here in the United States, both New York City and Seattle have allowed for single-stair construction for decades, with no measurable increase in fire deaths. Lowering the impacts of fires and allowing for more incremental apartment buildings are not mutually exclusive.
Let’s teleport, for a moment, to Puget Sound, where we can see exactly what we’ve been missing. For decades, builders have been taking advantage of Seattle's greater flexibility to build on smaller and narrower lots, putting in more homes in places where people want to live.
Capitol Hill Urban Cohousing, the Greta Apartments, and Jansen Court, all built according to Seattle's less stringent exit rules. (Sources: Schemata Workshop, CAST Architecture, B9 Architects.)
Take, for example, the Greta Apartments, over in the University District, with 33 units in four stories on a narrow lot. Or Jansen Court, with 10 stacked studios with a single stair in Capitol Hill. Or, nearby, Capitol Hill Urban Cohousing, with nine apartments and office space on the ground floor.
A small reform like legalizing these single-stair buildings would dramatically improve the building potential of our urban neighborhoods in two ways: They would allow for more interesting forms and for more decentralized investment. We could move away from the oblong five-over-one, which requires large lots (and deep pockets), and shift toward a model with a greater variety of people shaping their place.
Other existing single-stair structures in Somerville and Cambridge, Massachusetts, that could become much more economically feasible to build with single-stair reform.
We can look to the older structures, like Oak Terrace — buildings that are both useful and cherished — and work to ensure that we are not ruling them out. We can allow for structures that help to build a sense of community and kinship, for a greater diversity of buildings, and for the decentralization of the people building them, opening the door for Oak Terrace to be reborn.
Noah Harper is a writer, planner, urbanist and Strong Towns member focused on kickstarting incremental growth in communities. He writes regularly at powerandplace.substack.com.
