(Illustration via Pixabay by Peggy Marco)

THE HOUSING AFFORDABILITY crunch is an easy metric to quantify in broad terms, but it’s harder to express its human impact.

For me, it has meant friends and co-workers have either left the state for lower-cost areas, or they have put life on hold by putting off the possibility of switching careers, starting a business, or raising kids because they are not able to save enough money for their own home. High costs and inflexible options have meant they either have to leave their community or compromise on quality-of-life decisions — an American dream forestalled.

Massachusetts single-family home prices have increased over the last 50 years more than those in any other state, and the average price of a home in Greater Boston today is close to $750,000 — meaning a family needs to make double the median income to afford the average home. A major reason our housing continues to grow further out of reach for more people each year is that we do not build enough of it.

While many obstacles get in the way of building more housing, including zoning, permitting, and construction costs, the state building code itself remains an underappreciated factor in lagging development. One requirement of the building code — to have two staircases in any multifamily structure above three stories — is finally being acknowledged as a major obstacle to housing production and design in our communities and around the country.

This requirement stems from the 1800s and predates many modern safety features like sprinklers, fireproof construction, and fire detection technology. It is a uniquely North American requirement, and is the primary reason why we alone build multifamily housing in bulky, hotel-style configurations, while the rest of the world constructs more flexibly sized, ventilated, and naturally lit housing.

Raising the height threshold for single-stair buildings — those with just one staircase — from three stories to six or seven would save money on the stairway itself, but also open more living space. Indeed, it would unlock the math on many developments deemed unbuildable today, and open up the opportunity for more family-sized home layouts, which are currently hard to build when two staircases and a hallway take up all the space.

A single stair for a small building can cost up to $300,000, and its removal would both save costs and add back that space (typically around 7 percent of the floor area) to the rentable or salable side of the ledger. This allows single-stair buildings to save approximately 6 percent to 13 percent in construction costs compared to two-stair developments of the same size.

In 2024, I co-wrote with Utile, Boston Indicators, and the Harvard Joint Center for Housing Studies a report outlining how allowing single-stair mid-rise buildings could add both more and better-designed housing in Massachusetts. It showed how single-stair buildings fit more efficiently on our cozy New England-sized parcels, unlocking the potential for new homes that currently remain out of reach. It also detailed how these kinds of buildings have more daylight, access to natural ventilation, and can create family-sized homes.

While that report covered safety issues briefly through comparative data and case studies, two recent reports now address in greater detail both the risk assessment of proposed single-stair buildings and the historical record of fire safety for these buildings.

A draft report released in December, commissioned by the State of Minnesota and conducted by a consortium of fire protection engineering firms, compared typical two-stair, hotel-style buildings with comparable single-stair buildings. The study found that proposed single-stair buildings of up to seven stories would be overwhelmingly safe. Importantly, it found that the greatest risk of smoke blocking the way out of the building is not related to the number of stairs, but rather the length of the corridor, which might fill with smoke if a fire is not contained.

The findings also showed that the kinds of multifamily we build most of, where many homes share a common internal corridor, is actually vastly more dangerous than single-stair buildings, which are smaller and have fewer residents per corridor or stair. In their analysis, single-stair buildings of seven stories would put 80% fewer occupants at risk than a two-stair building of similar height. The report goes on to outline how simple safety upgrades, such as more smoke detectors or better sprinkler inspection, testing, and maintenance, could make mid-rise single-stair buildings as safe as low-rise single-stair buildings, making them almost 10 times safer than their mid-rise two-stair alternative.

The second recent report, from the Pew Charitable Trusts in 2025, looked at the safety record of existing single-stair buildings in Seattle and New York City, which have allowed single-stair buildings over three stories for decades. Their study found that there was not a single fire-related death in a building fire in either city that could be attributed to the lack of a second exit. Fire data consistently show that the greatest danger of life safety is within older and smaller buildings, particularly houses and duplexes.

As the population grows and housing in Greater Boston becomes more expensive, the number of new homes permitted is far below historic levels. High interest rates, trade frictions, and difficult market conditions raise construction costs, threatening our ability to build the homes we need at accessible prices. Allowing new single-stair development — combined with upzoning initiatives — enables us to provide more residents with safer homes in amenity-rich, transit-oriented neighborhoods across all our cities and towns.

Cities and states across the country have started to change their building codes. Nearly every other state in New England — Vermont dating back decades, and Maine, New Hampshire, and Connecticut more recently — has either changed or committed to changing its building code to allow four stories to be served by a single stairway. Texas, Colorado, Tennessee, and Oregon have or will soon allow cities to permit these kinds of buildings up to five or six stories; Minnesota is moving towards a statewide allowance of four stories.

Last month, Gov. Healey signed an executive order to explore allowing single-stair buildings up to six stories. The order was a welcome move that built on our work on bills filed in the Massachusetts House and Senate that would have established a similar commission to study single-stair buildings. Meanwhile, I have submitted a proposal to the same effect to the state’s Board of Building Regulations and Standards, which is currently reviewing it. Yet, this change could still take over a decade to implement. Even if the appointed group finishes its work this year and the state code is changed the next, a built example that implements the new standard is still, conservatively, 15 years out from being inhabited, assuming a consistent lag in code adoption, plus permitting and construction.

Families in Massachusetts can’t afford to wait 15 more years for solutions. If the state’s official process needs more resources to safely evaluate and hasten changes, we should invest in that process right now. If that same process also needs more voices to diversify issues in housing design and construction, we should also institutionalize participation from a wider pool of people so that the code development process integrates weighs the cost and benefits of our regulations against their real-world impact.

Our initial report made it clear that the hotel-style buildings we’ve long relied on to create new homes don’t fit on New England’s smaller lots and don’t allow for the family-style apartments that generations can live fulfilling lives in. Now, these new reports dispel the notion that two-stair buildings are safer, and in fact, are most likely more dangerous than proposed single-stair alternatives.

In addition to the safety benefits, we know that single-stair buildings have more opportunities for daylight, fresh air, and floorplan layout diversity — all in smaller building footprints where more intimate residential communities can form. I know which kind of building I would rather raise my family in, and which building creates a future where we can afford to live. Unfortunately, it’s the same kind of building that does not yet exist.

But this future is entirely within our control, and it doesn’t have to take more than a decade or two to make homes like this a reality. We can study the issue, we can work with urgency, we can update our codes – or we can continue with business as usual. Let’s get to work, for my family and yours.

Sam Naylor is an architect and partner at Nominal, a Boston- and Minneapolis-based architecture firm, and an adjunct associate professor in practice at the University of Minnesota.