Labeled by Fast Company as “Goldilocks” zones, the sweet spot for office buildings with the potential to become residential are ones that are mid-rise, built pre-WWII, with at least two sides facing open areas or streets near, but not within, a city’s financial core. According to San Francisco-based architect and structural engineer Charles F. Bloszies, the challenge with converting some office buildings lies in their large floor plates and lack of street exposure. Bloszies and his firm have been using publicly accessible data from the San Francisco Planning Department to identify offices that meet the ideal conversion characteristics.

This approach could be done in almost any city says Bloszies, and with higher office vacancies, greater housing demand, and lower real estate costs, this is an opportune moment to convert offices. There’s even the potential to make use of larger, downtown office buildings, which, through updated urban planning policies, could transform into logistics facilities or data sites. New zoning laws and policy changes will allow for new ways to repurpose spaces for in-demand uses. Bloszies likens this trend to the way tech companies occupied vacant warehouse buildings in San Francisco after light and heavy industry had left the city.