Roofing
Full roof replacements and repairs with GAF-certified shingles and a 50-year warranty. Most jobs done in 3–5 days.
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CSLB #1078806 · Architect & General Contractor · Building Northern California homes since 2018
Napa County’s Top Design-Build & Exteriors Contractor
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Factory-certified by our manufacturer partners
What We Build 
Custom Home & Exterior Services in Napa County
Siding
James Hardie fiber cement siding that protects your home and looks great for decades. We handle dry rot repair and full replacements.
Windows
Energy-efficient window replacements that transform comfort and curb appeal. Double-hung, casement, bay, and more.
ADUs
Detached ADUs, garage conversions, and junior ADUs. Design, permits, and construction from start to finish.
Custom Homes
Ground-up custom home construction tailored to your vision. From foundation to finishing touches.
Additions
Seamless room additions that match your home’s existing style. We handle permits, design, and construction.
Building in Napa County: What Homeowners Need to Know
Napa County blends wine country charm with demanding construction requirements. The county’s Wildland-Urban Interface (WUI) zones extend across much of the valley’s hillsides, from the slopes above Calistoga and St. Helena to the eastern ridges near American Canyon. After the 2017 Atlas and Tubbs fires and the 2020 Glass Fire, Napa County adopted some of California’s strictest fire-resistant building standards. New roofing in WUI zones must meet Class A fire ratings, and siding materials must comply with SFM 12-7A-1 ignition-resistance testing.
Permit requirements vary significantly across Napa County’s jurisdictions. The City of Napa processes roofing permits in 3–5 business days for straightforward replacements, while unincorporated county areas — where many vineyard estates and rural homes are located — may require additional environmental review, particularly for properties adjacent to Napa County Agricultural Preserve land. St. Helena and Calistoga both have design review requirements for exterior modifications visible from their historic main streets.
Napa’s climate is hotter and drier than the rest of the Bay Area, with summer temperatures regularly exceeding 95°F in the upper valley. This heat drives material selection toward cool-roof-rated shingles that reflect solar radiant heat and reduce attic temperatures by up to 30°F. We install GAF Timberline CS shingles with Cool Series technology for Napa homeowners seeking both fire resistance and energy efficiency. For siding, James Hardie’s ColorPlus factory-finished panels resist Napa’s UV exposure better than field-painted alternatives.
The architectural character of Napa County ranges from Victorian-era homes in downtown Napa to Mediterranean-style estates in Yountville and rustic modern farmhouses in St. Helena. Hamilton Exteriors works with each community’s aesthetic, ensuring that roofing and siding selections complement the neighborhood character. Our team has completed projects throughout the valley — from post-fire rebuilds in the eastern hills to full exterior renovations on Yountville cottages and American Canyon tract homes.
Rated 4.8 ★ from 39 Verified Northern California Homeowners
What Homeowners Say About Our Work
Real reviews from verified Northern California homeowners.
deborah maxey
a week ago
Great job and very professional the 1st photo is before and the other 2 is upon completion of work.
E
Eric W.
via Yelp
Hamilton Exteriors did an amazing job on my roof. The team was professional, and the quality of work was top-notch. Highly recommend!
R
Robert H.
via Angi
From the very first consultation, we knew we'd made the right choice. The team was knowledgeable and genuinely listened to our concerns about energy efficiency and design. We've already noticed a drop in our energy bills.
L
Laura G.
via Nextdoor
Hamilton Exteriors repaired extensive dry rot damage on our home's exterior. Their attention to detail and commitment to quality were evident throughout the project. Our home looks better than ever.
Our Advantage Why Choose
Why Choose
Hamilton Exteriors?
Transparent Pricing
Every estimate is itemized line by line — materials, labor, permits, cleanup. You see exactly where your money goes before we start.
Factory Trained Installers
Every crew member is manufacturer-certified and vetted — licensed, bonded, insured, and background-checked before they touch your home.
50-Year Warranty
50-year manufacturer warranty backed by our own workmanship guarantee for the full duration. If anything fails, we fix it — free.
Your Own Project Manager
One dedicated point of contact from first call to final walkthrough. You’ll always know who to reach.
Frequently Asked Questions
Didn't find the answer to your question? Call Now (650) 977-3351
What areas do you serve?
We serve Northern California across three regions: the San Francisco Bay Area (six counties from Alameda to Santa Clara), Greater Sacramento (Sacramento out to Roseville, Folsom, and Davis), and the Central Valley (Stockton to Modesto). Our crews are based in Castro Valley. We handle permits and know the building codes for each jurisdiction, which matters because requirements and fees vary significantly between cities.
How does billing and financing work?
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.
Are you licensed and insured?
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.
Do I need a permit for my exterior project?
Most exterior projects in Northern California 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.
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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 →