About the Founder
Alexander Hamilton Li
Architect & General Contractor • CSLB #1078806 • Castro Valley, CA
Background
I founded Hamilton Exteriors in 2018 in Castro Valley, California, with a simple idea: Bay Area homeowners deserve a contractor who brings an architect's eye to every project. Before starting the company, I worked in architecture and construction management, which gave me a deep understanding of both the design and execution sides of building.
Today, Hamilton Exteriors is a full-service design-build contractor serving homeowners across Alameda, Contra Costa, Marin, Napa, San Mateo, and Santa Clara counties. We have completed more than 500 projects — from single-day roof repairs in Oakland to ground-up custom homes in Palo Alto.
Credentials & Certifications
- CSLB License #1078806 — California Contractors State License Board. Verify on CSLB.ca.gov
- GAF Master Elite Contractor — Only 2% of roofers in the country qualify. Factory-certified installer with enhanced manufacturer warranty eligibility.
- Owens Corning Preferred Contractor — Platinum-level certification for roofing excellence.
- CertainTeed ShingleMaster — Advanced certification in shingle roofing systems.
- James Hardie Elite Preferred Contractor — Certified installer of James Hardie fiber cement siding.
- Licensed, Bonded & Insured — General liability and workers' compensation coverage on every project.
What I Do at Hamilton Exteriors
I oversee every project from the initial inspection through final walkthrough. My background in architecture means I think about how materials, design, and craftsmanship come together — not just whether the shingles are nailed straight. Every estimate I write is fully itemized line by line, and every project gets a dedicated project manager who reports to me directly.
Our services include roofing (asphalt, metal, tile, and flat), James Hardie fiber cement siding, energy-efficient window replacements, ADU construction, home additions, and custom homes. We handle all Bay Area building permits and know the codes for every jurisdiction we serve.
What Makes Bay Area Roofing and Exteriors Different?
The Bay Area has unique building challenges that national contractors often miss. Wildland-Urban Interface fire zones in the Oakland Hills, Berkeley Hills, and Marin require specific Class A fire-rated materials and installation methods that comply with California Chapter 7A standards. Coastal fog in San Francisco and Pacifica accelerates roof wear differently than the inland heat of Walnut Creek and San Ramon — salt-laden marine air corrodes exposed flashing and can halve the life of untreated metal components. Older housing stock in Oakland — roughly 60% built before 1960, according to the U.S. Census Bureau American Community Survey — often needs structural reinforcement before new materials go on. Every Bay Area jurisdiction also has its own permitting requirements, from San Francisco's historic district overlays to Marin County's defensible space inspections. I have worked in all six counties we serve, and our crews know how to handle every condition.
Get in Touch
Have a question about your home exterior project? I am happy to talk through it.
Phone: (650) 977-3351
Email: support@hamilton-exteriors.com
Office: 21634 Redwood Rd Unit F, Castro Valley, CA 94546
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21634 Redwood Rd Unit F, Castro Valley, CA 94546
Serving Oakland, Berkeley, Fremont, San Jose, Palo Alto, Walnut Creek, San Rafael, Napa, Redwood City & more across Alameda, Contra Costa, Marin, Napa, San Mateo & Santa Clara counties. All 47 cities →