San Francisco is a high-cost construction environment. A simple garage-to-ADU conversion may start around $150,000-200,000. More complex excavations or structural work can move significantly beyond that. The key is understanding what the city will require before walls open. I encourage clients to speak with contractors who specialize in San Francisco ADU and permit work, because early realistic estimates prevent budget shock later. Good contractors walk the space, review permit requirements, and give you a phased cost picture before you commit.
