Questions
Common ADU questions
Straight answers from our architect and builder. Don't see yours? Ask at a free site evaluation.
What is an Accessory Dwelling Unit (ADU)?
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a single-family residential lot. It can be attached to the main house, such as a basement apartment, or detached, like a small cottage in the backyard. ADUs add living space and can house family members, earn rental income, or serve as a home office.
What are the benefits of building an ADU?
An ADU increases property value and gives you flexibility for multigenerational living. It can also be a source of rental income to help offset mortgage costs, and it makes better use of land in urban areas.
What should I consider when designing an ADU?
Consider size, layout and how you'll use the space. Make sure the design complements the existing home and follows local zoning laws. Think about accessibility, energy efficiency, future changes, and privacy for both the ADU and the main house.
How much does it cost to build an ADU?
Costs vary with location, size and design. In the Bay Area, expect anywhere from about $100,000 for a garage conversion to upwards of $600,000 for a maximum-size ADU, including construction, permits and utility connections. Our configurator shows an all-in price for each of our plans.
What permits are required to build an ADU?
Most ADUs need a building permit, and some need a zoning permit or a variance if the project departs from local rules. We handle permitting for every A Mayberry ADU.
What are my financing options for an ADU?
Common options include home equity loans, personal loans, construction loans and refinancing your mortgage. Talk with a financial advisor about what fits your situation and project.
How do I maintain my ADU?
Plan routine inspections of plumbing, electrical and roofing, and keep up the landscaping around the ADU. A regular maintenance schedule helps prevent costly repairs.
What are the rental regulations for ADUs?
Rental rules vary by city. You may need a rental license and must follow occupancy limits and safety rules. A real estate attorney can help you stay compliant.
Do I need insurance for my ADU?
Yes. Insurance protects against damage, liability claims and loss of rental income. Review your homeowner's policy with your agent so it covers the ADU.
How can I make my ADU more sustainable?
Use energy-efficient appliances, solar panels, sustainable materials and water-saving fixtures, design for natural light, and landscape with native plants.
Is there anything I can do to speed up the process?
Yes. Get a hydrant flow letter from your water purveyor and a survey of your property, so we can quickly place the ADU and locate utilities. A topographic survey also helps place the ADU within the right boundaries.
How much can I build?
Under state law, an ADU can be 800 sq ft by right, and local agencies may not charge impact fees for ADUs under 750 sq ft. Height limits are 16 ft in all cases, 18 ft within half a mile of public transit or where the property already has a two-story multi-family dwelling, and 25 ft if attached to the main house, depending on local zoning. In San Jose, 18 ft single-story and 24 ft two-story ADUs are allowed.
Who is my water purveyor?
In San Jose, look it up with the city's utility services lookup. Once you know which of the three purveyors serves you, request a hydrant flow letter from them. In other cities, check the utilities department or your water bill.
How long is the construction timeline?
Our ADUs generally take about 6 months to build after the contract is signed in San Jose. Planning and permitting in other cities or counties typically add about 2 months for approvals.
Can I see your showroom?
We build each home in a client's yard, so we don't keep model homes. We do have 3D BIMx models of every plan so you can explore the space virtually, with VR walkthroughs coming soon. You're also welcome to visit our construction office to see materials and details.
What is the difference between Pre-Designed and Streamlined ADUs?
All our plans are pre-designed: the building drawings are complete with basic exterior finishes. Streamlined plans have also been through plan check with the city, which cuts permit time and hassle and sometimes city fees. Streamlined plans are available in San Jose, Napa and Sonoma Counties, Davis and Bakersfield. Contact us to see if your city has been added.
What about the interior finishes?
Choose one of our curated interior vibes and your project stays on our standard timeline. If you want to customize the plan or upgrade finishes, which may add cost, we schedule your project after you've selected every finish and approved the budget change.
I already have a builder or want to build it myself. Can I just get the plans?
We'll help you get the building permits, but we're selective about who builds an A Mayberry ADU so it looks right and lasts. That's why every client gets our warranty after construction.
Can I make changes to a Streamlined ADU?
Yes, but changes add cost and may affect the permit timeline.
I'm ready to move forward. What do I do next?
Configure your ADU in the configurator, then book a free site evaluation or email us at hello@amayberryadu.com. We'll respond right away.