In early March’s municipal elections, San Francisco made it easier for developers to turn empty office buildings into homes with the passage of Proposition C, which offers a tax break for developers to convert up to 5 million square feet of commercial space by 2030. San Francisco Mayor London Breed championed the proposal, saying it was necessary to address the city’s lack of affordable housing and revive its struggling downtown area. The measure comes as San Francisco’s office vacancy rate hit a record 36 percent in December and is expected to keep rising, according to an analysis by CBRE Group.