Sunnyvale / Accessory dwelling units
ADU Builder in Sunnyvale
Sunnyvale splits ADUs into a streamlined building-permit path and a path that needs a Miscellaneous Plan Permit first. The line the City publishes is 800 square feet for a new unit on a single-family lot. Conversions are listed with the streamlined group. For a Sunnyvale project, call our Cupertino office at (650) 562-6324.
Streamlined, or Miscellaneous Plan Permit first
On the City’s accessory dwelling unit page (opens in a new tab), a streamlined ADU needs a building permit and does not need a planning permit. The City lists new construction ADUs up to 800 square feet on single-family lots, conversion ADUs, junior ADUs, ADUs entirely within a new basement, and detached new construction on multifamily lots.
A new ADU larger than 800 square feet on a single-family lot is non-streamlined. The City says you apply for a Miscellaneous Plan Permit first. After Planning approves that permit, you submit the building permit. The City’s ADU brochure (opens in a new tab) describes the same split and points to Sunnyvale Municipal Code Chapter 19.79.
The brochure also says up to 800 square feet of each ADU is excluded from floor area and lot coverage, and it shows a 4-foot minimum side and rear setback for new construction ADUs. Chapter 19.79 is the code chapter to read with those summaries. Standards still depend on the lot and the unit type.
A plans gallery, not a shortcut around the lot
Sunnyvale offers a pre-approved ADU plans gallery from the same ADU page. A gallery plan can shorten drawing time. It does not decide whether your project is streamlined. Measure the proposed unit and confirm the permit path on the City page before you lock a design.
Which R&B number to use
Sunnyvale is served from our Cupertino office at 10080 N Wolfe Road, Suite SW3-200, Cupertino, CA 95014. The number on this page is (650) 562-6324. Our San Jose headquarters remains 84 W Santa Clara St, Suite 700, San Jose, CA 95113, and is listed on locations.
Questions homeowners ask
Is my Sunnyvale ADU streamlined?
Conversions and new ADUs ≤800 sq ft on single-family lots typically are. Over 800 sq ft new construction on single-family lots generally needs a Miscellaneous Plan Permit first.
What number should I call?
(650) 562-6324. That is the Cupertino office number we use for Sunnyvale projects.
Official sources
City rules change. The links below are the pages and documents these notes were checked against. Your address can still differ.
Talk with R&B
R&B Master Construction Inc. · CSLB #1158657. Email info@rbmasterconstruction.com. Headquarters: 84 W Santa Clara St, Suite 700, San Jose, CA 95113. Hours: Monday–Sunday, 7:00 AM–5:00 PM Pacific Time.