Contact Us: City Hall Address: 2263 Santa Clara Avenue Alameda, CA 94501 Floor Area: Show dimensions, size, height, conceptual floor plan, and total square footage of floor area in existing and proposed buildings.Once a complete set of plans has been prepared the next step is to submit them for review and approval. Plan Details ; Heated Space. Upper Floor328 sqft. Explore the design process in detail in our ADU Guidebook. Your go-to, in-depth guide to building an ADU in Alameda County, from inspiration to move-in. For an appointment or additional information, please call .