Allowing single stairwells in multifamily buildings could foster more affordable housing

Prevailing building codes that require two separate stairwells in multifamily buildings taller than three stories are stymieing development of affordable housing, according to some design and construction professionals.

The two-stairwell rule forces developers to allot more square footage to stairs, which removes space for living areas. That wasted space can be enough to make a project financially non-viable.

The impetus for two stairways in five-to-six-story buildings—fire safety—can be addressed with fire-stopping materials, sprinkler systems, and limits on the number of units, according to advocates of single-stairwell regulations. This would emulate codes in many European and Asian countries that have allowed single-stair development for decades.

The case for single-stairwell, mid-size multifamily buildings is gaining support in the U.S. Lawmakers in at least 10 states, including California, Oregon, and Washington, have either considered or passed legislation to allow such structures.