San Francisco infill boom

San Francisco’s latest building push is splitting in two directions at once: small infill on neighborhood lots and bigger towers on long-stalled sites. (sfyimby.com) (therealdeal.com) In the Castro, Golden Pacific Properties is floating a seven-story project at 2317-2335 Market Street that would add 24 apartments behind five two-story shophouses with retail at street level. The March 26 feasibility study says the rear addition would rise about 84 feet and include 22 one-bedrooms, two two-bedrooms, and two low-income deed-restricted units. (sfyimby.com) A few blocks from the city’s core, the One Oak site at 1500 Market Street is back before planners with a larger design: a 400-foot tower with 541 market-rate homes. Emerald Fund took over the project, removed the planned 2,500 square feet of retail, and argued that more units are needed to make the numbers work. (therealdeal.com) Mission Bay is moving on a different track, with housing and lab space rising side by side. A 2025 proposal for Mission Bay Block 4 East would build 400 affordable apartments in 16-story and 23-story buildings, while Gladstone Institutes signed a 105,000-square-foot lease at 1450 Owens Street for 30 new labs. (sfyimby.com) (therealdeal.com) City Hall is trying to make both kinds of projects easier to build. Mayor Daniel Lurie signed a downtown financing district on February 12, 2026 to support office-to-housing conversions, and San Francisco’s Family Zoning Plan took effect on January 12, 2026 after the city adopted it in December 2025. (sf.gov) (sfplanning.org 1) (sfplanning.org 2) The pressure behind that push is straightforward: San Francisco must zone for 82,000 additional homes under state housing law, and officials say the rezoning plan was required by January 31, 2026. The Planning Department’s housing inventory for 2025 also says it tracks projects that are completed, authorized, under review, or still in the pipeline. (sf.gov) (sfplanning.org 1) (sfplanning.org 2) Downtown’s office market is another reason developers are chasing odd-shaped parcels and alternate uses. CBRE said San Francisco’s overall office vacancy rate was 30.4% in the first quarter of 2026, while the city’s own dashboard says vacancy has not returned to its pre-pandemic level after hitting a record low of 4.70% in the second quarter of 2019. (cbre.com) (sf.gov) The biotech side is less simple than the cranes suggest. Gladstone’s expansion is one of the year’s larger leases, but the institute said it is growing even after a 10% drop in National Institutes of Health funding last year, a sign that some Mission Bay demand is holding while other life-science projects face tighter financing. (therealdeal.com) Developers and city officials are also not describing the boom the same way. Dan Sider, a city spokesperson, told The Real Deal that San Francisco was ready to keep approving One Oak, while a source close to the project said the tower’s feasibility still depends on future rent growth. (therealdeal.com) That leaves San Francisco with a building cycle defined less by one skyline-changing megaproject than by many bets at different scales: 24 units behind Castro storefronts, 541 units at Market and Van Ness, 400 affordable homes in Mission Bay, and 105,000 square feet of new lab space on Owens Street. (sfyimby.com) (therealdeal.com) (sfyimby.com) (therealdeal.com)