ADU costs in the Bay Area range from $100,000–$180,000 for garage conversions, $150,000–$250,000 for attached ADUs, and $200,000–$400,000+ for detached ADUs. The wide range depends on size, finishes, site conditions, and city. Barcci Builders provides a detailed fixed-price quote after your feasibility assessment — no surprises.

A typical ADU project takes 8–14 months from design to move-in: 1–2 months for design and engineering, 2–4 months for permits (California law now requires cities to approve ADUs within 60 days), and 4–8 months for construction depending on size and complexity.

Under California law, detached ADUs can be up to 1,200 sq ft. Attached ADUs can be up to 50% of the existing home's living area (with a minimum of 800 sq ft allowed). Junior ADUs (JADUs) can be up to 500 sq ft and must be within the existing home's footprint.

Yes. ADUs require building permits from your city or county. However, California's ADU laws (AB 68, SB 13, AB 881) have dramatically streamlined the process — cities must approve or deny ADU applications within 60 days, and many fees have been reduced or eliminated. Barcci Builders handles the entire permitting process for every project.

Yes. ADUs in California can be rented as long-term rentals (30+ days) on any property, including single-family and multifamily lots. In the Bay Area, ADUs typically rent for $2,200–$4,500/month depending on size, location, and amenities. Some cities allow short-term rentals; check local ordinances.

A Junior ADU (JADU) is a unit up to 500 sq ft created entirely within the existing footprint of a single-family home — typically converting a bedroom, garage attached to the main house, or unused space. JADUs require a separate entrance, an efficiency kitchen, and a bathroom (which can be shared with the main house). They're the fastest, lowest-cost ADU option.

California state law sets a minimum standard: 4-foot rear and side setbacks for detached ADUs up to 16 feet in height. Some cities apply stricter rules or allow reduced setbacks in specific zones. Front setback rules for the main house still apply. Barcci Builders knows the exact setback requirements for every city we serve.

Most single-family and multifamily properties in California can have at least one ADU. Properties with a single-family home can have one ADU plus one JADU. Multifamily properties can convert unused non-livable space into ADUs and may be able to add detached ADUs in parking areas. Some properties have restrictions — we assess your specific lot during the free feasibility consultation.

A detached ADU is a completely separate, new structure built in your backyard. A garage conversion repurposes your existing attached or detached garage into livable space. Garage conversions cost significantly less ($100K–$180K) because the structure already exists, but you lose parking. Detached ADUs cost more ($200K–$400K+) but preserve parking and add more square footage.

Yes, significantly. In the Bay Area, a well-built ADU typically adds $200,000–$500,000+ to your home's appraised value, while costing $150,000–$350,000 to build. ADUs also generate rental income that can offset your mortgage. According to Zillow, homes with ADUs sell for 35% more than comparable homes without them in high-cost metros like the Bay Area.