ADU Contractor in Union City

We serve six Bay Area counties — Alameda, Contra Costa, Marin, Napa, San Mateo, and Santa Clara — covering 47 cities from Oakland to San Jose. Our crews are based in Castro Valley, putting us within 45 minutes of every city we serve. We handle permits and know the building codes for each jurisdiction, which matters because requirements and fees vary significantly between cities.

We offer $0-down financing with approved credit, 12-month same-as-cash plans, and extended terms up to 15 years for larger projects. You only pay for completed, inspected work — we never ask for full payment before the job is done. Your project manager will walk you through every option during your estimate appointment. We also accept checks, ACH, and all major credit cards.

Yes. CSLB License #1078806 — verify it anytime at cslb.ca.gov. We carry $2M general liability, full workers’ comp, and are bonded per California law. We hold GAF Master Elite, Owens Corning Preferred, CertainTeed ShingleMaster, and James Hardie Elite Preferred certifications — each requires annual training and quality audits to maintain. We’re happy to provide proof of insurance before any work begins.

Most exterior projects in the Bay Area require a building permit. Fees vary by city — Oakland runs $200–$600, Peninsula cities often more. We handle the entire permit process: application, plan submission, and scheduling inspections. Permit fees appear as a separate line item in your estimate so you’ll see every cost upfront. For homes in WUI fire zones (Berkeley Hills, Oakland Hills, parts of Marin), we ensure full compliance with local fire-rated material requirements.

ADU costs in Union City typically range from $150,000 to $350,000 depending on size, finishes, and whether it's a new build or garage conversion. With median home prices at $1,050,000, an ADU can add significant value. We provide free consultations with detailed estimates.

California's ADU laws make it possible to build on most residential lots in Union City. Alameda County has streamlined the permitting process. We evaluate your property's potential during our free consultation, including setbacks, utility access, and local zoning.

From design to move-in, most ADU projects in Union City take 8-12 months. The Alameda County permitting process typically takes 60-90 days, and construction runs 4-6 months. Our 60-day permit guarantee keeps your timeline on track.

Yes. We handle all ADU permitting in Union City and throughout Alameda County — architectural plans, structural engineering, Title 24 energy compliance, and city submissions. Our 60-day permit guarantee means we manage the entire process.

In Union City, you can build detached ADUs (up to 1,200 sq ft), garage conversions, attached additions, and junior ADUs (up to 500 sq ft). Many homeowners in Hillview are choosing detached ADUs for rental income or multi-generational living.

ADU construction in Union City typically ranges from $150,000-$350,000 depending on size, finishes, and site conditions. A 400 sq ft studio starts lower, while an 800+ sq ft two-bedroom with full kitchen runs higher. Hamilton Exteriors provides detailed estimates after site evaluation.

ADU permits in Union City require plan submittal through the city's building department. California AB 68 and SB 9 streamlined ADU approvals statewide. Hamilton Exteriors handles architectural drawings, engineering, permit applications, and all inspections from start to finish.

Most single-family lots in Union City qualify for at least one ADU under current California law. Minimum lot size requirements have been largely eliminated by state legislation. Key factors include setback compliance, utility access, and lot coverage. We evaluate your property's eligibility during a free consultation.

Yes. California law allows ADU owners to rent to long-term tenants. Union City may have specific regulations regarding short-term rental platforms. An ADU typically generates $1,500-$3,000+ monthly rental income in Alameda County, making it a strong investment.

California state law limits rear and side setbacks to 4 feet for detached ADUs. Union City may have additional guidelines for specific zones. Attached ADUs follow the primary dwelling's setback rules. Hamilton Exteriors designs each project to maximize usable space within code requirements.