Single-Stair Advocacy

Design research report & advocacy around legalizing single-stair housing in Massachusetts

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Report by Utile, Boston Indicators, and Harvard Joint Center for Housing
40 Pages
2024

Existing Code
Proposed Changes
 Nominal (Sam Naylor) was the primary co-author of a recent report on building code reform in Massachussetts. The report and research focsuses on updating our building codes to allow for small and mid-sized apartment buildings to only have one egress stair. This small change would have an outsized impact on the feasibility of missing middle housing, and would allow a greater livibility in our housing that is currently built in mostly sub-par double-loaded podium style buildings.

The report was released on October 11, 2024. Subsequently the “Unlocking Housing Production Commission” put together by Governor Healey released its report, “Building for Tomorrow,” which made suggestions for policy reforms—one of which was single-stair reform. There are now two bills in the house and senate to study this issue further. Nominal has also testified on these bills and submitted an official code request to the BBRS.



Download Full Report PDF

Current MA Bills (H.1542 - House) (S.964 - Senate)

Hearing Testimony

Official BBRS Code Change Request

See our Denver Design Proposal









Press  Coverage

 Events





Resources


  Center for Building in North America

   Second Egress CA

  Public Architecture Report

  SAR+ Single-Stair Research



Single-stair buildings or Point Access Blocks (PABs) provide much more opportunity for sunlight exposure. This allows units to be more naturally and passively lit, to be naturally cross-ventilated, and to have more bedrooms (be family sized). 




Cross ventilation and daylight are key to creating sustainable buildings that use less energy and are more resilient in the face of unkown climate futures or present emergencies. These are possible and common in PAB units, but are very rare and disincentivized in status quo double-loaded units. 




 In typical double-loaded multifamily buildings units can only grow in one dimension. This makes larger family sized units have extra space in the back—space that is not daylit, and which remains a burden on their financial performance. PAB units in contrast have more diverse arrangements possible, and can provide family sized units with just as good efficiency as smaller units.








The current development conext of Greater Boston rarely produces multifamily housing in buildings with more than 9 units or less than 45 units. This is a direct result of zoning, regulatory, and building code thresholds that make development at this scale expensive or illegal. The requirement for two staircases in buildings more than three stories or 12 units is key to this condition, and removing this barrier for modest apartment buildings will make them finally possible.


















The scale of single-stair apartment buildings being proposed by this advocacy are small. The current legal limit for a two-stair floor plan can contain far more units per stair and contains a more dangerous corridor condition due to smoke accumulation, lack of compartementalization, and length of exit access. 






Compared to the rest of the world Massachusetts (in addition to much of the US & Canada) is an outlier. Mid-rise PABs are the globally accepted norm for urban housing production. Favored because they offer livability at scale, without the downsides of hotel-style-housing. 













The current proposal in Massachussetts seeks to raise the limit from 3 stories to 6 stories for PABs. 











Raising our single-egress-stair (SES) limit to 6 stories, or around the high-rise limit, is on par with a globally accepted norm. The safety of these buildings is clear from the range of their acceptance, and a new report has also examined how even in US juristictions where they are legal, they remain just as, if not more, safe than the status quo. 




To test the applicability of this housing type across Greater Boston we analysized suitable parcels for development. Over 5,000 parcels were identified which were underutilized, too small for current building types, and which were near transit.

These parcels were then grouped into three categories by size, and analyzed for their most average size and shape.



Six total test fits (two for each parcel type) were drawn to roughly estimate unit counts. Various forms of PAB plans were tested, including: barbell, single-loaded, perimeter block, party-wall, front-back, and multi-building. 








Under this proposal, and using conservative estimates for which parcels might be built on we estimated over 130,000 new housing units could be built in the near future. This represents a massive dent in the supply shortage and also an exciting prospect for production that can be unlocked by just updating our codes to represent the future we want to build, for everyone. 



© 2025 Nominal LLC