We specialize in ADUs
If you’re a homeowner in the East Bay looking to maximize your property’s potential, finding the right partner is essential. Accessory Dwelling Units (ADUs) have become a popular solution for property owners who want to add extra space, whether for multi-generational living, rental income, or simply creating a private space for family members.
At Type Five, we specialize in designing and building customized ADUs and single-family home construction projects throughout the East Bay. Type Five's approach combines innovative modular design with high quality craftsmanship and transparent pricing to bring your vision to life.
As a full-service architecture firm and general contractor based in Berkeley, Type Five is deeply rooted in the East Bay community. We hold in-depth expertise on local regulations and the unique challenges of adding an accessory dwelling unit on the same lot as your main home. Our team’s local experience ensures that your ADU project complies with San Francisco Bay Area requirements while maximizing your property’s value. Many homeowners trust Type Five because of our honest, professional approach and commitment to clear communication throughout the entire construction process.
Your ADU project partner
Choosing the best ADU builder in the East Bay means partnering with a team that values your vision and needs. At Type Five, we guide you through every step of your ADU building journey, from initial planning to move-in day. Our focus and experience with accessory dwelling units ensures your new home is both functional and made to last.
Whether you’re interested in generating passive income through a rental unit or creating a private space for out-of-town guests, we tailor our services to meet your goals. Our design options accommodate various square foot requirements and can includes customized kitchen and bathroom designs to ensure a comfortable, functional living area. Type Five prioritizes transparent communication, so you always know where your project stands, helping you avoid surprises and delays common in construction.
What sets Type Five apart?
Type Five stands out among East Bay ADU builders because of our software-enabled modular design system. Our novel software allows you to configure your design online, choosing the layout, finishes, and features that suit your needs. Our team’s dedication to honest, professional service makes us one of the top ADU specialists in the East Bay. With every Type Five home, we aim to prioritize the following outcomes:
- A seamless process: transparent design and construction pricing and timelines from the jump. No guesswork, no runaway budgets, no stress.
- Thoughtful design: creative and practical expertise to give build an ADU that will maximize space and increase your property value
- Quality craft: our obsessive attention to detail makes luxury accessible for all, giving you more space to live comfortably.
- A hundred-year home: we’re a leading Bay Area ADU builder for a reason—our accessory dwelling units excel in both form and function that stand the test of time.
What our clients say
Don’t just take our word for it—our clients love our professionalism, quality of work, and seamless project management. Read more in-depth client testimonials.
“I feel like we got all the benefits of a custom build, without the uncertainty.”
"The design process with Type Five felt more streamlined, and the experience allowed us to stay focused and avoid being overwhelmed by too many options."
"Type Five was really attractive because that's what they were offering: a full-service construction company with an established design system."
Tell us more about your ADU project
Every ADU project is unique, and we want to hear about your vision. By understanding your lifestyle and budget, we help turn your dream ADU into a reality. Schedule a free consultation to discuss your ADU project, and learn more about working with us.
How our process works
Our customized experience sets the standard for ease, transparency, and quality.
FAQs about ADU building in the East Bay
Here’s what most people want to know about our process and services.
Are you a prefab ADU company?
No. We’re a design‑build firm that constructs every ADU on‑site. Your Type Five ADU is built from the ground up in your backyard – no cranes or oversized trucks – letting us customize to your property and needs while still capturing some prefab‑style efficiencies.
Can I build an ADU on my property? How many ADUs can I have?
State law guarantees at least one ADU on a single‑family lot. You’re also allowed one Junior ADU (JADU) inside the existing house. Multifamily lots may add up to two detached ADUs plus JADUs in unused interior space, so many owners can build two units in total.
How long does it take to design, permit and build an ADU?
Design phase ≈ 1 month (faster if you’re decisive).
Permitting phase ≈ 2–4 months once we submit plans.
Construction phase ≈ 6 months on‑site.
Most projects take about 10–12 months from first design meeting to move‑in.
What are the advantages of working with a design-build contractor like Type Five?
One point of contact from concept to keys.
Plans in hours, not weeks, using proprietary software.
Guaranteed pricing because design and construction live under one roof.
No finger‑pointing – we own the result and the warranty.
What types of permits and city approvals do I need to build an ADU?
Type Five secures everything: planning approval, building permit, fire‑department sign‑off, utility coordination, and any other agency reviews. You just sign an authorization form and we handle the rest.
What financing options do homeowners have for an ADU?
Common options include cash‑out refinance, HELOC, home‑equity loan, construction loan, or personal/family financing. We can connect you with lenders experienced in ADU projects.
How will building an ADU affect my property taxes?
Your main house assessment stays unchanged under Prop 13. The assessor adds the ADU value separately, typically increasing your annual bill by about 1 % of the ADU’s construction cost.
Can I use an ADU for generating rental income?
Yes, you can absolutely use an ADU to generate rental income, and in many East Bay cities it’s one of the most common reasons homeowners build one.
What is the difference between an ADU and a tiny home?
An ADU is a permanent, permitted residential structure on your property, while a tiny home may not meet local building codes or be allowed as a legal dwelling.