Resources for Reformers: Single-Stair Midrise Buildings

As a sense of urgency builds around North America’s housing affordability crisis, researchers have begun to look beyond zoning and permitting for ways to build more housing for less money. In the wake of a movement to bring more mass timber buildings to the US and Canada, some have turned their attention to the role of building codes. 

The first building code issue to receive sustained grassroots attention is the requirement, listed in the International Building Code (despite the name, a code mostly in use in the US), for buildings over three stories to have two exit staircases connected by a corridor. This requirement has long been in effect in most of the United States, with the exception of New York City, Seattle, and recently Honolulu and Knoxville (and a few other areas with modified versions of the requirement, as detailed in this Niskanen Center report.) Architect Sean Jursnick and developer Peter LiFari’s policy brief for Mercatus is a good general survey of the issue; for a discussion of local reforms that also interviews many of the key players, also read Patrick Sisson’s article in The Architect’s Newspaper. 

State legislators in Tennessee, Washington, Oregon, California, Connecticut, Virginia, and Minnesota have passed legislation directing their states’ building councils to consider – or simply approve – single-stair buildings up to six stories. Bills to similar effect were also introduced but not passed last year in New York and Pennsylvania; this year, bills are being considered in Colorado, Hawaii, Kentucky, Maryland, Massachusetts, Montana, New Jersey, and Texas. Los Angeles city councilmember Nithya Raman has also introduced a motion to update the building code there, and Austin is debating such a motion as well.

Mechanisms of reform

A policy brief for HUD’s Cityscape journal by Stephen Smith of the Center for Building in North America (and of this blog) and Eduardo Mendoza of the Livable Communities Initiative overviews the issue, with detail on the history of point access blocks and the specific regulations which have shaped the built environment in the US and Canada. Key points include:

• It is difficult to put building codes on a solid empirical grounding, since they are usually shaped in response to individual, thankfully rare tragedies.
• There’s a feedback loop between the national building codes and state and local building codes, whose innovations can shape what makes it into national standards, as was the case with mass timber construction.
• Stair redundancy rules are only one of several paths to building safety; others include compartmentation (using fire-resistant walls and floors to restrict fire from spreading beyond its origin), fire sprinklers, and materials restrictions.

Responses to fire concerns

Since fire safety is the rationale for the second staircase requirement, much of the resistance to reform has come from fire departments. The National Fire Protection Association (NFPA) has reasonably impartial coverage of the debate, including in a feature for their journal by Jesse Roman, as well as the report NFPA put out from their symposium on the issue on September 11-12, 2024. Speaking in favor of reform was Stephen Smith, as one of the leaders of the reform movement. Smith’s presentation at the NFPA symposium features ideas which can also be found in the report he compiled along with researchers for Pew Charitable Trusts. The Pew report contains the most robust empirical evidence that allowing midrise single-stair buildings need not compromise fire safety, but there are also theoretic and broad-strokes reasons not to be dissuaded by fire safety concerns.

Empirical evidence:

• The Pew study, by Smith along with Sandip Trivedi and Pew researchers Seva Rodnyansky, Alex Horowitz, Liz Clifford, and Dennis Su, examined all fire death records in New York City in midrise buildings since the city began permitting single-stair buildings up to six stories. The authors found no difference in death rates between single-stair and multiple-stair buildings of the same size, and no death could be blamed specifically on the absence of a second stair.
• Authors also reference a Dutch study on preventing deaths from the spread of smoke (Fire Service Academy, “Smoke Propagation in Residential Buildings,” 2020) which did not find a second staircase to be a relevant factor in slowing the spread of smoke. Smith points out in the NFPA presentation that smoke spread is a bigger issue in contemporary fires than fire spread, due to sprinkler requirements and the increased use of plastics in consumer products which are toxic when burned.

Besides the review of fire deaths, researchers advance some other responses to fire safety concerns: 

• Because multifamily buildings have other fire safety requirements that are more stringent than those for single-family homes, discouraging multifamily construction could be counterproductive for fire safety.
• In some cases, the second staircase itself could be bad for fire safety, since if the idea is for firefighters to block off one staircase to attack the fire, that doubles the distance someone right next to that stair would have to cross to evacuate.
• Overall, the United States and Canada have worse fire safety outcomes than many countries which allow single-stair multistory buildings – in some cases much higher than six stories. (Many writers cite this FEMA report.) It’s worth noting that building out of wood is much more common in the US and Canada than in those countries, but the overall safety record is nevertheless proof that tall single-stair buildings need not be death traps.
• US cities that allow single-stair midrise buildings do not have fire department response times significantly longer than other cities.
• Most current North American codes also do not distinguish between combustible and non-combustible building materials when imposing the second-stair requirement.
• There are other restrictions which can deliver fire safety at lower cost, such as sprinkler requirements, already in place currently.

Note: Resources specific to single-stair that I’ve seen don’t address the fire safety implications of fewer new buildings being built. I can’t speak to a direct fire safety comparison between buildings built to new vs. old standards, but at the very least: crowding, people using invalid lodgings like basements as housing, people living somewhere where the building management doesn’t know they’re there, substandard insulation leading people to rely on space heaters, and homelessness (via homeless people relying on propane tanks for heat and cooking) would all seem to increase fire safety risks – and all of those increase as housing supply gets more constrained. Then there are the costs of building or upgrading fire stations and employing a fire brigade, which I would guess also increase when buildings are hard to build.

Cost comparisons

One of the primary benefits of allowing single-stair midrise buildings is it would get more buildings built, especially on dense urban infill lots, because the second stair is an expensive use of space which can’t be rented out. 

• The Pew study provides a quantitative estimate for these cost savings of 6-13%, based on a case study of a building in Jersey City, where rents are high enough to justify building even with the second stair.
• In addition, they note small apartments are often where the lowest rents can be found.
• Michael Eliason, a Seattle-based architect and principal partner at architecture firm Larch Labs, is one of the most influential voices in, and arguably the founder of, the movement to legalize point access blocks in North America. In his 2021 report for the city of Vancouver, “Unlocking Livable, Resilient, Decarbonized Housing with Point Access Blocks,” Eliason estimates an average cost savings of CAN$37,500 per floor (USD$26,180).
• Eliason also notes that allowing midrise single-stair buildings could make vertical additions to existing buildings more feasible.
• Smith and Mendoza point out the high cost of lot assembly in Los Angeles for larger buildings (driving up the price of land by up to 40% according to a 2016 study); single-stair buildings are easier to build on existing lots.

Livability impacts

As an architect, Eliason’s primary focus is building good buildings. His 2021 report and 2023 policy brief lay out his case for the benefits of midrise single-stair buildings beyond being cheaper to build, as do Jursnick and LiFari in their brief for Mercatus.

Key points:

• More flexible floor plates allow for more possible unit configurations, including more three-plus-bedroom apartments suitable for families.
• This diversity of unit configurations also allows for units which get light and ventilation on multiple sides, and makes it easier to shield bedrooms from noise and air pollution.
• The compactness of the building design makes them more energy-efficient.
• The space not used for the second staircase could be used as a common area, and the flexibility of form makes it more possible for the stairway itself to be a social space.
• The possibility of a mixed-use building with a smaller footprint than what’s currently common opens up opportunities for more small businesses, rather than just grocery stores and similar, to avail themselves of ground-floor retail space.

Coverage of jurisdictions that have made or are considering changes

Reports have been commissioned for Massachusetts and British Columbia specifically. 

• The BC report, compiled by PUBLIC Architecture, contrasts point access blocks with other building types. 
• The Massachusetts report, by Utile Architecture & Planning, has a comprehensive alternative set of fire safety standards, proposes additional reforms, and estimates that allowing midrise point access blocks could conceivably result in an additional 130,000 units built in Greater Boston (vs. the region’s goal of 200,000 new homes by 2030).
• In addition, Conrad Speckert, an architect in Canada and another of the leading lights of the movement, maintains a timeline on his website of research and legislation.
• Sean Jursnick’s Mercatus brief about Seattle includes many photos of point access blocks as well as a history of how the “Seattle Special” came to be.

Examples of single-stair architecture

Both Speckert and Eliason provide visualizations of midrise single-stair developments in jurisdictions that allow them and blueprints for such developments. Speckert’s “Manual of Illegal Floor Plans” gathers many of these in one place. Eliason’s 2021 article for Treehugger, “The Case for More Single Stair Buildings in the US,” goes into detail on how European (especially German) cities ensure fire safety, and also shows several examples of European single-stair buildings.

Broader efforts to reform building codes

Smith’s organization, the Center for Building in North America, researches the cost and livability impacts of building codes generally, including research on elevator codes. For the Cato Institute, Emily Hamilton makes an argument for reforms to the International Code Council’s way of doing business, including benefit-cost analysis and a more technocratic update process.