Additions 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.

Second-story additions in Union City cost $275 to $400 per square foot. An 800 sq ft upper floor with two bedrooms and a bath typically runs $220,000 to $320,000 including structural reinforcement. Union City's mid-range labor market keeps costs lower than Oakland or Alameda.

Yes. Most 1970s-80s Union City homes have foundations designed for single-story loads. Adding a second story requires new footings at load-bearing points and steel moment frames. The flat terrain and stable soils in Union City simplify this work compared to hillside communities.

Union City's building division typically processes residential addition permits in 8 to 14 weeks. There is no historic design review requirement for standard homes, which saves 2 to 3 months compared to some East Bay cities. Hamilton Exteriors submits complete permit packages to avoid revision delays.

Second-story additions preserve your yard and avoid lot coverage limits. Ground-floor extensions are less expensive but consume outdoor space. For Union City's 1970s ranches on 5,000 to 6,000 sq ft lots, going up is usually the better investment because the lots are not large enough for significant ground-level expansion.

Yes. Adding a primary suite or bonus room over the garage is one of the most popular second-story additions in Union City. The garage foundation often needs reinforcement, but the work does not disrupt the main living areas. Typical cost for a 400 sq ft room over the garage is $120,000 to $180,000.

For most of the 5 to 7 month construction period, you can stay in the home. The exception is a 2 to 3 week window when we remove the existing roof and frame the upper floor. We install temporary weather protection and recommend short-term relocation during this phase.

Union City allows a maximum building height of 35 feet in most residential zones. A two-story home with 9-foot ceilings and standard roof pitch fits comfortably within this limit. We confirm your parcel's specific zoning during the initial consultation.

Alameda County reassesses only the value of new construction. An 800 sq ft second-story addition at $300/sq ft construction value adds approximately $2,400 to $3,000 per year in property taxes. Your existing home's assessed value does not change.

Yes. Split-level homes have a partial upper level that can be extended to cover the lower sections. This is often more straightforward than adding a full second story to a ranch because the structure already handles some vertical load. We design the extension to integrate with the existing split-level roofline.

Yes. We prepare architectural drawings, structural engineering plans, Title 24 energy calculations, and all required documentation. We submit to Union City's building division, respond to plan check comments, and schedule all inspections throughout construction.