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Stone and Stryder work on Accessory dwelling units continues. Here we share our work on converting a garage to an ADU at 3440 20th Street, San Francisco, CA.
As owner's representative we provided a comprehensive range of services for the project, including a feasibility study, financial underwriting, project planning, design management, permitting and approvals, contracting, financial management, construction management, and closeout.
The building, originally constructed in 1965, comprised four stories and 39 existing units. The total rentable square footage was 22,545 square feet, with an average unit size of 578 square feet. The first floor featured a large garage with 40 parking spaces, a trash room, a laundry room, and the building's mechanical systems.
For the construction of the ADUs, the project involved repurposing the garage and storage areas while relocating the water heaters and communication equipment. Within the 7,640 square foot area, nine new ADUs were developed, consisting of four 2-bedroom and 1-bathroom units, three 1-bedroom and 1-bathroom units, and two studios. This resulted in total new rentable square feet of 6,248, with an average unit size of 694 square feet.
The project encountered several challenges, such as adhering to Residential Transit Oriented zoning regulations, which necessitated specific unit mix design considerations. Other challenges included relocating leased parking spaces, replacing a significant portion of the building's perimeter foundation, and relocating multiple support columns. Additionally, complexities arose from the relocation and upgrade of the main electrical panel, involving the installation of a new transformer in a street vault. The project also encompassed the relocation and replacement of the building's water heaters and the building’s communication equipment.
The addition of the nine new units increased the building's unit density by 23%. Based on a 5% stabilized cap rate, this created a net increase in the building's value of nearly $2,900,000.
