ADU Construction Contractor
in Richmond, CA
Building a new accessory dwelling unit from the ground up gives you the most flexibility of any ADU option — you're not limited by an existing garage footprint or the layout of your current home. You choose the size, the placement on your lot, and the finishes, and you end up with a unit purpose-built as a home from day one rather than a converted structure.
Richmond has approved 372 ADUs since 2019, and ground-up construction accounts for a growing share of that as more homeowners with larger lots opt for detached, standalone units instead of converting existing space.
What's Involved in New ADU Construction
- Site evaluation — placement, setbacks, utility access, soil conditions
- Custom floor plans and 3D renderings before anything breaks ground
- Foundation, framing, roofing, and full exterior build-out
- Plumbing, electrical, and HVAC installed from scratch
- Interior finishing — flooring, cabinetry, fixtures, appliances
- Final inspections and certificate of occupancy
Because you're building new rather than converting, there's more upfront design work — but also more control. We handle placement to maximize privacy, sunlight, and yard usability rather than just fitting the unit wherever it's easiest to build.
Lot Size and Setback Requirements
Under California Government Code §65852.2, Richmond must allow at least one ADU per single-family lot regardless of lot size, though setbacks still apply — typically 4 feet from rear and interior side property lines for detached units. Height limits generally cap at 16 feet for detached ADUs, though additional height is allowed in some cases if the unit is within a half-mile of transit. We pull your specific lot's zoning during the initial site visit rather than quoting generic numbers that may not apply to your parcel.
Permitting in Richmond
New ADU construction goes through the same Planning Division and Building Division review as any other ADU project, but with more documentation since there's no existing structure to reference — full structural calculations, foundation plans, and Title 24 energy compliance are all required from scratch. Richmond is required by state law to approve or deny a complete application within 60 days. We prepare and submit the entire package and manage all communication with the city, so you're not the one chasing down plan check comments.
Richmond also offers free pre-approved ADU plans for qualifying projects — using one can shave real time off the design and review phase. We'll tell you during your consultation if your lot is a good fit.
ADU Construction Cost in Richmond
Ground-up ADU construction in Richmond typically runs $150,000–$360,000, depending on size, foundation type, and finish level. This is the most expensive path of the four ADU options since you're paying for a full foundation and structure — but it's also the only path that gives you complete control over layout and design.
Richmond's ADU grant program offers up to $40,000 toward pre-development and non-recurring closing costs, which is worth applying for before you lock in a budget.
ROI: A well-placed, well-built detached ADU tends to add more resale value than a conversion, since buyers see it as genuinely new square footage rather than repurposed space. Many Richmond homeowners recoup costs within 5-8 years through rental income alone.
Why Build New Instead of Converting
- No compromise on layout — designed as a home, not adapted from one
- Full privacy from the main house with its own entrance and yard access
- Better long-term durability since everything is new construction
- Most flexibility for future use — long-term rental, family housing, or resale value
Frequently Asked Questions:
New ADU Construction in Richmond, CA
Do I need a permit for new ADU construction in Richmond?
Yes — full building permits are required before any site work begins. Plans go through Planning Division review for zoning compliance, then Building Division review for code compliance. We handle the complete submission: architectural drawings, structural calculations, Title 24 forms, and site plans.
How big can my ADU be?
Detached ADUs in Richmond can be built up to 1,200 sq ft for a single-family lot, though actual buildable size also depends on setbacks, lot coverage limits, and how much of your yard you want to give up. We'll walk your specific lot to give you a realistic max.
How long does new ADU construction take?
Typically 6-18 months from initial design to move-in, depending on size and complexity. That includes 4-8 weeks for permit review and several months of construction. New builds take longer than conversions because there's a full foundation and structure to build rather than repurpose.
Can I build an ADU if I have a small backyard?
Often, yes. Setback requirements are typically just 4 feet from rear and side property lines for detached units, which leaves more buildable area than most homeowners expect. We'll assess your specific lot during the consultation — sometimes a smaller, well-placed unit works better than trying to maximize square footage.
Do I need to add parking for a new ADU?
Under California Government Code §65852.2, no additional parking is required if your property is within a half-mile of a public transit stop — which covers most of Richmond given BART and AC Transit coverage. We confirm this for your address before finalizing plans.
What's the difference between building new and converting a garage?
New construction gives you full design freedom and typically higher long-term value, but costs more and takes longer since you're building a foundation and structure from nothing. A garage conversion reuses what's already there, which is faster and cheaper but limits you to the existing footprint. We'll walk you through which makes more sense for your goals and lot during the consultation.
Will a new ADU increase my property taxes?
Yes — new construction triggers a reassessment, but only on the value of the new unit, not your existing home. Your primary residence's assessed value stays the same. Check with the Contra Costa County Assessor for details specific to your parcel.
What happens if I want to sell my property after building an ADU?
A permitted, well-built ADU typically adds resale value and can be marketed as additional legal square footage or rental income potential. Unpermitted units create disclosure problems and can complicate a sale — which is exactly why full permitting matters even though it takes longer.
Related Services
Ready to talk through what a new ADU could look like on your lot? Schedule a consultation or call 510-890-0106.