Detached ADUs in San Diego County
A separate backyard living space starts with the property and the way you want to use it.
Discuss your ADU projectPlan a separate space for the way you live
Kingstone Building builds detached backyard ADUs and coordinates residential construction from early planning through completion. The first conversation establishes the property, intended use, timing, and the type of space you want to create.
Family living space and future flexibility are part of the existing ADU offering. The right design and construction scope depend on your property.
Make the first plan useful
The ADU planner lets you choose a starting size, layout, finishes, and known site conditions. It returns a preliminary planning range or flags the project for review when the property needs a closer look.
Location, access, utilities, and existing conditions influence the construction path. Final pricing follows a site visit, confirmed plans, and a written proposal. See our process for the steps described on the website.
Considering an existing garage instead?
A garage conversion begins with the existing structure, access, utilities, and scope. Discuss both options before choosing a direction. Find your community on the service areas page.
Start with your property.
Request a consultationADU questions before you build
Get clear answers about ADU budgets, timing, permits, and rental planning. For guidance specific to your property, request a consultation.
How much does an ADU cost?
For a detached ADU with standard finishes and straightforward site conditions, use $250,000 to $350,000 as an initial planning budget. The ADU planner calculates a size-specific preliminary construction price, which can fall outside that range. This planning budget excludes major grading, utility upgrades, and agency fees. We confirm final pricing after a property review, confirmed plans, and a written proposal.
What is the typical ADU timeline?
Plan for about 12 months: three months for planning and design, three for permit review, and six for construction. The final schedule depends on your property, project scope, and approvals.
What permits are needed for an ADU in San Diego?
The permit process moves through design preparation, application review, any required corrections, approval, construction inspections, and final sign-off. The responsible city or San Diego County agency confirms the requirements, fees, and review process for your property.
How does a garage conversion compare with a detached ADU?
A garage conversion works within an existing garage footprint; a detached ADU is a separate backyard unit. Garage conversions depend on the existing structure, access, utilities, and scope. Kingstone Building reviews the property before presenting project pricing. The right approach depends on the property and intended use.
What rental income could an ADU generate?
At a monthly rent of $2,500, an ADU generates $30,000 a year in gross rent. Vacancy, maintenance, insurance, financing, and other expenses reduce net income. The rent achievable for your ADU depends on the unit, location, and rental market.