ADU Builder Union City
Custom, High-Quality Accessory Dwelling Units
Are you looking to build an Accessory Dwelling Unit (ADU) in Union City, CA?
Keep Your Family Close with a Custom ADU
Whether you want to create a comfortable space for aging parents, independent living for adult children, or a guest house for extended family, ADU Builders Group is your trusted ADU builder Union City, California.
With over 20 years of experience, we specialize in designing and constructing high-quality, custom-built ADUs that strengthen family bonds, enhance multigenerational living, and improve your lifestyle while ensuring compliance with local building regulations.
Build with Peace of Mind
We are the only ADU company in Union City that offers a three (3) years project warranty on our services with complementary annual project inspection. All of this on top of the ten (10) years warranty on structural components.
✔ 3 Years Project Warranty
✔ Complimentary Annual Inspection
✔ 10 Years Structural Warranty
Why Choose Us?
1. Peace of Mind with Industry-Leading Warranties
✅ 3 Years Project Warranty – We stand by our craftsmanship, ensuring any issues within the first three years are addressed promptly and professionally.
✅ Free Annual Inspection – Our commitment to quality extends beyond project completion, we provide a free annual inspection, for the first three years after project completion, to ensure your ADU remains in excellent condition.
✅ 10 Years Structural Warranty – Our ADUs are built to last, and we back them with a decade-long structural warranty, giving you confidence in the longevity of your investment.
2. Expert Guidance & Hassle-Free Process
✅ Permitting & Compliance Experts – Navigating Sunnyvale's ADU regulations can be complex, but our experienced team ensures a smooth approval process, handling all paperwork and city requirements to prevent costly delays.
✅ 20+ Years of Construction Expertise – With decades of expertise in the construction industry and a dedicated focus on ADUs for over five years, we bring the knowledge, efficiency, and craftsmanship necessary to deliver high-quality results every time.
✅ Fast & Efficient Construction – Our streamlined process and skilled project management ensure your ADU is completed on time without unnecessary disruptions to your daily life.
3. Superior Craftsmanship & Custom Designs
✅ Aging-in-Place & Accessibility Features – Our ADUs are designed with the future in mind, incorporating accessibility features such as wider doorways, step-free entrances, and senior-friendly layouts for long-term convenience.
✅ Tailored Solutions for Every Home – Every family’s needs are unique, which is why we create custom ADU designs that maximize space efficiency, match your home’s aesthetics, and fit your lifestyle.
✅ High-Quality Materials & Precision Engineering – We use only top-tier materials sourced from our trusted, high-quality suppliers, ensuring that your ADU is durable, safe, and built to last for generations.
4. A Lifestyle Solution for Your Family's Needs
✅ Keep Loved Ones Close – Give elderly parents or adult children a private yet nearby living space, ensuring family members stay connected while maintaining their independence.
✅ Multigenerational Living Made Easy – Whether it's providing a comfortable home for aging parents or giving young adults a head start, our ADUs foster a supportive and practical living arrangement.
✅ Enhance Your Home’s Functionality – More than just extra space, an ADU can serve as a dedicated home office, personal gym, creative studio, or even a guest house for visiting relatives and friends.
About Us
Partners and Affiliations
ADU Builders Group Inc.
ADU Builders Group is a local, family-owned company dedicated to providing innovative solutions to California’s housing crisis, with passion for helping multigenerational families. Having high regards to family-oriented values, our work reflects a deep commitment to creating practical, high-quality custom ADUs that bring loved ones closer while respecting privacy and independence. With heart, craftsmanship, and a focus on community, we build homes that inspire and unite.
✔ Proudly Local
✔ Family-Owned
✔ Licensed and Insured
A Partner & Sister-Company of
Imagine Unique Remodels
Our Services and Expertise
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What's The Best Type of ADU for You?
Our Process
Consult with our ADU Experts
1
To start, discuss your needs, goals, and vision for your ADU with our experts. Start by having a phone consultation with us at (408) 413-3373. We'll set your schedule for the in-person meeting during the call. You'll receive expert recommendations and estimate for your ADU during the consultation phase at no cost.
2
Design with our Architect
Need to customize your ADU based on your needs and requirements? Design your own ADU and turn your ideas into an architectural plan with our Architect.
4
Construct & Pass Inspections
Our Project Managers will be in constant communication with you during construction and will ensure that your projects pass all inspections.
3
Obtain Permits Effortlessly
Our Liaison Officer will take care of the permits for you and work with the city to ensure that all paperworks are in place quickly and efficiently.
5
Enjoy and Maintain your ADU
Live the lifestyle you want and be worry-free. We'll continue to provide support and care to your project with our warranties and annual project inspection.
Local ADU Regulations in Union City
Below is an overview of ADU regulations in Union City. If you need more details about how these rules apply to your property, contact us to get connected with an ADU expert.
Where ADUs Are Allowed
ADUs are generally permitted on residential properties, though there may be exceptions. Your property must have an existing or planned single-family home or a multi-family building, such as a duplex, triplex, or apartment complex. Reach out to us to determine if your property qualifies for an ADU.
Minimum Lot Size
There are no minimum lot size requirements—any property, regardless of its dimensions, may be eligible for an ADU.
Number of ADUs Allowed
Most single-family homes can accommodate one or two ADUs. Multi-family properties may qualify for multiple ADUs depending on the number of existing units and the type of ADU being built. Get in touch with our team to find out how many ADUs your property can support.
Parking Requirements
Conversion and junior ADUs generally do not require additional parking. However, attached and detached ADUs typically require at least one parking space unless an exemption applies. Reach out to us for expert guidance on Union City’s ADU parking regulations.
Featured Project
ADU Builder Union City FAQs
How long does it take to build a backyard home in Union City?
Most projects take 8 to 12 months from planning to completion. This includes 1–2 months for design, 2–4 months for permit approval, and 4–6 months for construction. Properties with unique site challenges or older infrastructure may require additional time.
What’s the average cost to build a compact second unit?
Homeowners typically spend $450 to $500 per square foot, depending on layout, materials, and site conditions. A 750 sq. ft. in-law suite or guest house might start around $340,000, while larger builds can exceed $475,000. Be sure to account for permit fees, utility connections, and site preparation.
Can the new living space use existing utilities?
Yes, most backyard cottages and other small dwellings can share water, sewer, and electrical lines with the primary home. That said, separate meters may be required for rentals or preferred for managing usage. Some older homes may need panel upgrades or plumbing improvements.
Are there sustainability incentives for energy-efficient construction?
Yes! Union City residents can access BayREN rebates, as well as programs for solar panels, EV chargers, and energy-efficient appliances. All new construction must meet California Title 24 energy codes, and units under 750 sq. ft. are typically exempt from impact fees.
Why are more homeowners adding secondary dwellings?
These smaller units offer flexible living space for aging family members, young adults, or tenants. They’re also a smart investment for those seeking rental income or a private work-from-home space—without needing to move or expand the main house.
Is there demand for these kinds of homes in Union City?
Yes, especially with rising housing costs and limited rental availability in the area. Many property owners are choosing to build garage conversions, detached units, or basement suites to support multigenerational living or generate income.
What design styles are popular locally?
Homeowners often choose modern studios, traditional guest cottages, or energy-efficient one-bedroom layouts. Features like open floor plans, large windows, smart home tech, and outdoor patios are frequently requested for both comfort and functionality.
Where can I get help understanding local building requirements?
The Union City Planning Division provides online access to zoning info, permit guides, and development standards. You can also schedule a pre-application consultation with staff to review your specific lot and design ideas.
Will adding a second unit change the look of my neighborhood?
Not drastically. The city enforces clear rules around setbacks, building height, privacy, and design compatibility to ensure that new homes fit well within existing neighborhoods while adding subtle, much-needed housing options.
Do I have to provide extra parking?
Not always. If your compact home is within ½ mile of public transit, part of a garage or basement conversion, or meets other state exemptions, no additional parking is required. Otherwise, you may need to provide one off-street space.
Service Areas
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