Detached ADU near Castro Valley, CA

CDU Inc. offers expert ADU construction & remodeling in the Greater Bay Area. Services include new builds, garage conversions, electrical, plumbing & custom design to boost property value & functionality.

HDR Remodeling is a Bay Area Design Build firm since 1987, specializing in kitchen remodels, bathroom renovations, and home improvements across Oakland, Berkeley, Alameda, and the East Bay, backed by an experienced team of architects and designers... read more

Diagram Architecture & Diagram Design Build completed a 871 sq ft detached ADU with 2 beds, 1.5 baths, open floor plan, stainless appliances, custom closets & natural light—maximizing compact living through integrated design-build expert... read more

Whether you’re planning a rental unit, a guest house, or a private suite for family, RenoRevive will help you design and build a fully functional ADU that fits your needs, your lot, and your long-term goals.

Samara's Backyard ADU offers prefab accessory dwelling units for California homeowners. Five sizes available, including the 950 sq ft XL 10. Factory-built, fire-resistant, energy-efficient, with full-service permitting, installation & flexible... read more

ENE Smarthome, Inc. is a Bay Area contractor offering home remodeling, ADU construction, smart home upgrades, and accessibility improvements. Services include garage conversions, granny flats, aging-in-place remodels, and SB9-compliant ADU project... read more

Bay Area general contractor Design and Construction by M&M specializes in ADUs, remodeling, room additions, and custom builds. Serving Burlingame, Los Altos, and Campbell, they manage design, permitting, and construction. Free consultations av... read more

Wise Builders is a Bay Area ADU contractor with 20+ years of experience in accessory dwelling units, garage conversions, and attached or detached ADU construction across San Jose, Sunnyvale, and Silicon Valley. Free estimates available.

Wellmade is a California prefab ADU builder specializing in panelized accessory dwelling units. Founded in 2020, they've completed 200+ projects, reducing construction waste by 85%. Serving CA, OR, and WA with all-inclusive pricing.

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.

Apex ADU Builders is a Los Angeles-based contractor specializing in accessory dwelling unit construction. Services include new builds, garage conversions, permitting, and design. Costs range from $80K–$400K, with potential ROI 35% higher than ho... read more

Jaws Construction Services builds ADUs, garage conversions, and JADUs. They handle permits, HOA coordination, and offer site-built or prefab options. East Bay ADUs rent for $1,500–$3,500+/month, potentially boosting property value.

prefabADU is a Bay Area ADU builder with 16+ years of experience offering affordable kits and plans from under $45K. With 12 state-approved plans valid across California, they simplify permits, design, and installation for homeowners.

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.