Home Additions in Orinda, CA
Get a Free Orinda Addition Consultation
Growing an Orinda Home on a Hillside Lot
Orinda homes often have room to grow on the lot but not on flat ground. We design additions that work with the slope: step-down family rooms, primary suites over garages, second stories and bump-outs that open the house to decks and views.
Additions We Built
Will Your Addition Need Design Review?
In Orinda, design review is required for:
- New second stories
- Additions over 1,000 sq ft
- Projects on lots with an average slope of 20% or more
- All new homes
A modest single-story addition on a flatter lot can often skip design review and go from Planning approval straight to County plan check.
The Orinda Addition Permit Path
Orinda City Hall, Planning Department
22 Orinda Way, Orinda, CA 94563 · (925) 253-4200
Planning applications and building permit authorizations are filed online through the City’s Cloudpermit portal.
- Zoning check at City Hall. Orinda Planning confirms setbacks, height, floor area, and whether your project needs design review.
- City planning review in Cloudpermit. Orinda reviews the project before the County will issue anything. Additions that trigger design review go through that review before the building permit.
- Fire district review by the Moraga-Orinda Fire District (MOFD) where the project requires it.
- County plan check through ePermits, with the City-approved plans.
- County inspections through construction, then final sign-off.
Contra Costa County Department of Conservation and Development
30 Muir Road, Martinez, CA 94553 · Permit Center (925) 655-2700
Submittals are digital through the County ePermits Center. The County’s Lamorinda field office closed in March 2023. Inspections are requested through ePermits or the County inspection line, (925) 646-4108.
Other Orinda Factors
- Wildfire: new exterior walls, roofs, vents and windows must meet California’s wildfire building standards, because MOFD treats its whole district as a Wildland-Urban Interface community.
- Sprinklers: under Contra Costa County’s building rules, additions to a home without sprinklers do not trigger them unless the project removes or replaces at least 50% of the wall length and 50% of the roof within a year. We confirm with MOFD early.
- Oaks and creeks: protected oaks and creek setbacks can limit where an addition can go.
Addition or ADU?
If you want separate living space with its own kitchen and entry, an Orinda ADU is reviewed ministerially and can be faster to approve than a large addition. Read ADU vs. home addition.
Keep Exploring
More Axiom services in Orinda: ADU Builder · Bathroom Remodeling · Kitchen Remodeling · New Home Construction · Orinda overview
Nearby: Lafayette · Moraga · Walnut Creek · All service areas
See our home additions page.
Orinda Home Additions FAQ
Does an addition in Orinda need design review?
New second stories, additions over 1,000 sq ft and projects on lots averaging 20% slope or more do. Smaller additions often do not.
Will an addition require fire sprinklers in my Orinda home?
Under County rules, not unless the work removes or replaces at least half of the wall length and half of the roof within a year. MOFD can have its own requirements, so we confirm early.
Can I add a second story in Orinda?
Often, yes, with design review. Views, privacy and height are part of that review.
Where do I apply?
Planning review starts with the City of Orinda through Cloudpermit. The building permit is issued by Contra Costa County.