15-17 Castillo St, San Francisco, CA 94134

The two-unit residential building at 15-17 Castillo Street in Visitacion Valley, owned by David Tang, is a two-story flats and duplex structure built in 1948. The property's most significant recent improvements occurred in 2013, when substantial renovations were completed to enhance safety and living conditions.

These improvements included the installation of fire-rated walls between the garage and habitable areas, along with the construction of new living spaces comprising a playroom, exercise room, and bathroom on the ground floor. During this renovation phase, comprehensive updates were made to the building's mechanical systems, including the installation of two new furnaces with flue pipes, complete electrical system upgrades with the installation of lighting, outlets, and smoke detectors, as well as plumbing improvements including new bathroom facilities.

Prior to these renovations, the building underwent an electrical system upgrade in 2005, which included a 200-amp service upgrade and the installation of additional electrical infrastructure. The 2013 renovations, which carried a reported cost of $35,000, were particularly focused on improving safety through fire separation measures and modernizing the building's systems, including a complete electrical and plumbing overhaul along with HVAC improvements. All permits for these modifications show a "Complete" status, indicating successful completion of the work.