Looking for a reliable general contractor in Antioch, CA? Hamilton Exteriors brings architect-led design-build expertise to your home. We handle roofing, siding, window replacement, ADU construction, home additions, and custom homes — all with the precision of a licensed architect and the accountability of a licensed general contractor.
Our founder, Alex Hamilton Li, is both an architect and a general contractor (CSLB #1078806). That dual credential means your project benefits from design thinking and construction execution under one roof. No handoffs between an architect who designs and a contractor who interprets. We do both.
We serve Antioch from our Castro Valley base and have completed projects across Contra Costa County. Get your free quote today by calling (650) 977-3351 or contacting us online.
Why Antioch Homeowners Choose Hamilton Exteriors
Antioch presents unique conditions that a generic contractor might overlook. Here is what we account for on every Antioch project.
Hot inland summers. Antioch regularly sees summer temperatures above 100°F, according to NOAA climate data. That thermal cycling — expansion and contraction from heat to cool Delta evenings — stresses roofing materials, siding, and window seals. We specify materials rated for high-temperature environments and use installation methods that accommodate thermal movement.
Seismic risk. Antioch sits near the Concord Fault and Hayward Fault, with higher liquefaction risk in the Delta zones, per the California Geological Survey. Our structural connections, foundation work, and shear wall details meet or exceed current California Building Code seismic requirements. Every addition and ADU we build in Antioch includes engineered hold-downs and proper load-path continuity.
Fire zone awareness. While much of Antioch itself is in a Local Responsibility Area, the East Bay hills and Diablo Range to the south are designated State Responsibility Area Very High Fire Hazard Severity Zones, per CAL FIRE's FHSZ maps. Homes on Antioch's southern edge and in nearby unincorporated areas may require Chapter 7A compliant materials. We assess every property for fire-zone applicability and specify materials accordingly.
Permitting through the City of Antioch. The Antioch Building Division handles all permits for residential work. We pull permits on every project and handle the application, inspection scheduling, and final sign-off. Permit fees in Antioch typically run $250 to $800 depending on project scope.
Our Services in Antioch
Roofing
Antioch's hot summers and Delta winds demand roofing that handles thermal stress and uplift. We install:
- Asphalt shingles (GAF, CertainTeed, Owens Corning): $940 to $1,125 per square installed. Includes tear-off, synthetic underlayment, ice-and-water shield at eaves, new flashing, and ridge vent. 30 to 50 year warranties.
- Metal roofing (standing seam, stone-coated steel): $1,200 to $1,800 per square. Class A fire rated, 40 to 70 year lifespan, reflects up to 70 percent of solar energy per Oak Ridge National Laboratory research.
- Tile roofing (clay, concrete): $1,500 to $2,500 per square. Common on Spanish-style homes in Antioch's newer subdivisions. Requires structural assessment for older homes.
A typical Antioch roof replacement on a 2,000 sq ft home runs $17,500 to $21,500 for asphalt shingles. See our roofing services page for details.
Siding
Antioch's temperature swings and Delta moisture can cause wood siding to warp and paint to fail prematurely. We install:
- James Hardie fiber cement siding: $8 to $15 per square foot installed. Non-combustible, resists moisture, carries a 30 year non-prorated warranty. We are a James Hardie Elite Preferred Contractor.
- Engineered wood siding (LP SmartSide): $6 to $10 per square foot. Treated for termite and fungal resistance.
- Stucco and EIFS: $8 to $14 per square foot. Common on Antioch's Mediterranean-style homes.
See our siding services page for material options and pricing.
Window Replacement
Single-pane windows are still common in Antioch's older homes. Replacing them with dual-pane, Low-E windows reduces cooling costs during 100°F summers and heating costs during Delta winter fog. We install:
- Vinyl windows: $600 to $1,200 per window installed (Hamilton Exteriors 2024-2026 project data). Energy Star certified, dual-pane, argon-filled.
- Fiberglass windows: $800 to $1,800 per window. More dimensionally stable than vinyl in extreme heat.
- Aluminum-clad wood windows: $1,200 to $2,500 per window. Premium option for historic or custom homes.
A full-home window replacement (10 to 15 windows) runs $8,000 to $25,000. See our window replacement services page.
ADU Construction
Antioch's zoning allows accessory dwelling units on most single-family lots. We handle the full process: design, engineering, permitting, and construction. Typical costs:
- Detached ADU (400 to 800 sq ft): $150,000 to $300,000
- Attached ADU (300 to 600 sq ft): $100,000 to $200,000
- Garage conversion: $60,000 to $120,000
All prices include design, permits, foundation, shell, MEP (mechanical, electrical, plumbing), and finishes. See our ADU construction services page and Bay Area ADU cost guide for detailed pricing.
Home Additions
Adding square footage to your Antioch home increases living space and property value. We design additions that match your existing architecture and meet current code. Typical costs:
- First-floor addition (200 to 500 sq ft): $80,000 to $200,000
- Second-story addition (400 to 800 sq ft): $200,000 to $400,000
- Room addition (single room, 150 to 300 sq ft): $60,000 to $150,000
All prices include architectural design, structural engineering, permits, and construction. See our home addition services page.
Custom Homes
For homeowners who want a ground-up build, we offer full custom home construction. We handle site planning, design, permitting, and construction. Costs vary widely based on size, complexity, and finishes. Typical range: $350 to $600 per square foot (Hamilton Exteriors 2024-2026 project data).
How We Price Projects
Every Hamilton Exteriors estimate is fully itemized. You see the cost of materials, labor, permits, and cleanup as separate line items. every line itemized, no vague ranges. We quote per-square pricing for roofing and per-square-foot pricing for siding, windows, and additions.
Our pricing includes:
- All materials and labor
- Building permits pulled by us
- Tear-off and disposal (roofing, siding)
- Manufacturer warranties (materials)
- Workmanship warranty (2 years standard, 25 years on GAF roofing systems)
Pricing does not include:
- Structural repairs discovered during demolition (we quote these as a contingency)
- Interior finishes beyond scope (for ADUs and additions, we define finish scope upfront)
- Landscaping or hardscaping outside the building footprint
Antioch Building Permits: What to Expect
The Antioch Building Division requires permits for most exterior work: roof replacement, siding replacement, window replacement, ADU construction, additions, and custom homes. Permit fees in Antioch range from $250 for a simple roof replacement to $2,000+ for an ADU or addition.
We handle the entire permit process:
- Submit plans and application to the Building Division
- Coordinate with plan check (structural, energy, fire)
- Schedule inspections at each milestone
- Obtain final certificate of occupancy or completion
Typical permit turnaround in Antioch is 2 to 4 weeks for standard projects, 4 to 8 weeks for ADUs and additions.
Get Your Free Quote
Ready to start your Antioch home project? Call us at (650) 977-3351 or Get Your Free Quote online. We'll schedule an on-site inspection and provide a fully itemized estimate within 48 hours.
Hamilton Exteriors. Architect-led. Contractor-built. Serving Antioch and all of Contra Costa County.
Alex Hamilton Li, Architect & General Contractor | CSLB #1078806
