Barcci Builders specializes in ADU construction across the Bay Area, offering design, permitting, and build services. With 40+ completed units, they handle JADUs, garage conversions, attached, and detached ADUs, with costs ranging from $60K to $400K+.
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Bao-Tran Builders Inc specializes in ADU construction, including detached ADUs, granny flats, JADUs, garage conversions & multi-unit properties. Expert ADU contractor delivering functional, high-quality housing solutions for property owners.
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Custom ADU builders in Palo Alto, CA, specializing in granny flats, detached ADUs & backyard cottages. Personalized design, permitting, and full construction management for quality accessory dwelling units.
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AKD Homes is a SF Bay Area ADU contractor with 20+ years of experience. They offer full-service ADU design, permits, and construction, including detached ADUs, granny flats, and custom builds ranging from 400–750 sq. ft.
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Apex Homes is a full-service ADU builder in the South Bay Area, serving Campbell, Palo Alto & South San Jose. They offer detached ADUs, granny flats & in-law suites, with pre-designed floor plans from $185,000.
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At Smith and Son Construction, they specialize in designing and building high-quality ADUs in San Leandro, CA. Whether you envision a private guest house, a rental unit, or a home office, they deliver innovative designs, expert craftsmanship, and a stress-free construction experience.
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We are a family-first, boutique residential design & build firm serving the Orinda and East Bay community. We’re not just service providers — we’re your neighbors. We understand the local permitting process, the hillside terrain, the fire-hazard restrictions, and the thoughtful planning needed to create homes that truly work for East Bay families.
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Geico Builders offers ADU services including detached ADUs, attached ADUs, Junior ADUs, garage conversions, and home additions. Ideal for rental income, family housing, or maximizing space on your existing property.
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Haus+ is a Bay Area ADU builder offering turnkey accessory dwelling units for California homeowners. They handle design, permitting, and construction using a panelized hybrid method, with all-inclusive upfront pricing and in-house financing available.
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Masterful Construction is a San Mateo ADU contractor serving the Bay Area. They build detached ADUs, garage conversions, and in-law suites, handling design, permits, and construction. Discounts available for military and first responders.
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J&A Builders Inc serves San Jose & the Bay Area with residential construction, remodeling, ADUs, second floor additions & garage conversions. Services include kitchen, bathroom, whole-home remodels & granny flats.
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Karl Kardel Company offers home remodeling, additions, and ADU construction in Oakland, Pasadena, and the Bay Area. Services include detached ADUs, garage conversions, granny flats, kitchen and bathroom renovations for residential properties.
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Custom Home is a Bay Area ADU contractor (CSLB #986048) with 160+ projects since 2005. They build detached, attached, junior ADUs & garage conversions across South Bay & Peninsula, with costs from $120K–$500K+.
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GADI Construction, led by Nadav, specializes in ADU construction, home expansions, garage conversions & granny flats. Known for detailed planning, clear communication & professional client guidance throughout every project phase.
read moreSan Mateo, California, sits at the heart of the San Francisco Peninsula, making it one of the most desirable — and expensive — housing markets in the nation. With median home prices consistently among the highest in the country, homeowners in San Mateo are increasingly turning to Accessory Dwelling Units (ADUs) as a smart way to add rental income, house family members, or increase property value. Finding experienced ADU contractors in San Mateo is the critical first step toward making this investment a reality.
San Mateo operates under both California state ADU law and its own local municipal code. The City of San Mateo has worked to align with state mandates that streamline ADU approvals, but there are still important local considerations every homeowner must understand before breaking ground:
Working with a licensed ADU contractor familiar with San Mateo's building department is essential. The city's permitting process involves plan checks, inspections, and compliance with the California Building Code, Title 24 energy standards, and local zoning ordinances. An experienced local contractor will know how to navigate the San Mateo Community Development Department, helping to avoid costly delays and revisions.
Given the variety of lot sizes and home styles across San Mateo neighborhoods — from the flat streets near downtown to hillside properties in areas like Sugarloaf — ADU contractors in San Mateo commonly build several types of units:
When selecting an ADU contractor in San Mateo, CA, look for professionals who are licensed by the California Contractors State License Board (CSLB), carry proper insurance, and have a proven portfolio of completed ADU projects in the Bay Area. Request detailed bids, check references, and confirm familiarity with San Mateo's specific permitting timelines. A qualified contractor will guide you from design and permitting through construction and final inspection, ensuring your ADU is built safely, legally, and on budget.