Stacked Flats With Single Entrances: Just As Safe in a Fire

Stacked Flats = AWESOME

In 2024, I wrote that “humble stacked flat” is one of the most important tools for increasing housing capacity in cities. It turns out that the most common objection to this building type–fire risk–is totally unwarranted. 

Stacked flats provide much more housing for the building footprint than do most new American apartments, because they waste far less space on excessive hallways and stairwells. They do this so well, in fact, that we can vastly increase our capacity to produce homes (more affordably!), make more of them family sized, and do a much better job than we are today when it comes to green space and trees.

They use space so well because they have a single entrance with stairs and, depending on the circumstances, an elevator. This means they don’t have two entrances and a big hotel style hallway down the middle. By wasting much less space–you build a lot of housing more cheaply. 

A study of the Boston area estimated that these could create 130,000 new homes on vacant lots a short walk from transit.

These homes also have more access to air and light. Most units are single story, which makes them better for families, seniors, and people living with disabilities. They are common in Europe, and this is (one reason why) European cities are much better for families and seniors than American cities. 

Because of their efficient use of building space, and their stackability, they can produce a lot more housing while taking up a lot less land. Using an example from the architect Mike Eliason, I compared a Seattle block to a block from Hamburg Germany. Hamburg’s has more space for more than twice as many people, and more space for trees, simply because single stair buildings (with no setback rules). 

However, these amazing buildings are not allowed in most US jurisdictions. 

The reason has always been–but what if people are trapped in a fire? (Why this is never raised for townhomes or detached single family homes is beyond me).

Proponents of stacked flats have long pointed out that death rates in stacked flat buildings– which are common in Europe–are no higher than in other buildings. But opponents always waived this away with the standard “but that’s Europe so it is just magically different somehow” objection that is far too common in US planning (and tax, and healthcare, and childcare) policy conversations.

Well, we have US data now, and it turns out, US single stair buildings are as safe as their hallway-filled peers. It turns out that all those intuitions about fires were wrong. Single stair buildings do not have a higher rate of fire deaths compared to other building types. In addition, in the extremely few fire deaths that did occur in the thousands of US single stair buildings during the more than decade long study period, none were related to the lack of a second stairway. It even turns out that the second stairwell and the hallway in traditional US buildings add smoke related safety risks. 

Right now, we have a system that does not produce enough housing for everyone, so people are left bidding up the scraps of what is available. If we made these modest, livable, lovely buildings legal in every neighborhood near public transportation, commercial areas, schools, or parks, we could create an affordable path to ending this bidding war by building the homes everyone needs.