L SQUAREDESIGN & BUILD
A separate backyard home planned around your property, privacy goals, utilities, access and local permit path by a licensed Orange County and Los Angeles design-build team.
A detached ADU is an independent dwelling in a separate backyard structure, with its own entrance, kitchen, bathroom and living space. It provides more physical separation than an attached ADU, while requiring a new building footprint, foundation, utility routes and property-specific access planning. L Square evaluates, designs and builds detached ADUs across Orange County and Los Angeles.
There is no reliable universal price per square foot or total price range for a custom detached ADU. A final written quote follows review of the property, site conditions, design, utilities, access and construction scope.
Review current ADU cost planning and property-specific cost drivers →
A detached ADU in Los Angeles follows the state-law framework but still requires the correct local review path. Properties inside the City of Los Angeles generally work through LADBS and City Planning where applicable; unincorporated Los Angeles County and independent cities use different agencies. Hillside, coastal, fire-access, utility, existing-structure and construction-access conditions can change feasibility, design and review. Confirm the jurisdiction and property conditions before selecting a plan or representing a schedule, and review Los Angeles ADU permitting and construction for the broader local process.
California law protects detached ADU pathways but does not make every maximum size or design available on every property. Start with the official California HCD ADU Handbook and Government Code section 66321, then confirm the local ordinance and property conditions.
A detached unit uses a separate building footprint, so the first review covers placement, setbacks, privacy, grading, drainage, utility routes, construction access and fire or life-safety conditions. Window, entry and outdoor-space decisions should protect privacy for both dwellings.
A detached ADU is a separate backyard building; an attached ADU shares a wall or structure with the primary home; a garage conversion reuses an existing structure. The better fit depends on usable footprint, privacy, structural work, utilities, access and project goals.
A coordinated ADU design-build scope connects feasibility, architecture, engineering, agency submittals, plan-check responses, construction and inspections. Review the Orange County ADU permit guide and confirm the responsible jurisdiction before relying on a plan.
One licensed design-build team coordinates detached ADU feasibility, architecture, engineering, permits, construction and inspections under one defined scope (CSLB #1095476). Property conditions and agency requirements are reviewed before the design and written construction scope are finalized.
Licensed · Insured · Bonded · CSLB #1095476 · Orange County & Los Angeles
Choose a detached ADU builder by asking for proof before promises. Confirm the active contractor license and exact business entity, then ask how the builder will review the jurisdiction, lot, access, utilities, privacy, drainage, fire or life-safety issues, and inspection path before design is treated as final. A reliable proposal should identify written assumptions, inclusions, exclusions, allowances, and who is accountable for design, engineering, permits, construction, corrections, inspections, and closeout. Real proof matters most when it matches the type of work being discussed.
A detached ADU price is reliable only after the property and scope have been reviewed together. A final quote should follow review of the intended unit, site access, foundation assumptions, utility routes, grading and drainage, finish level, agency path, engineering needs, and known exclusions. Early figures can help planning, but the contract price should come from a defined scope, not a generic detached-ADU average.
| Input | Why it matters |
|---|---|
| Jurisdiction and parcel basics | Confirms which city or county agency reviews the ADU and which local standards apply. |
| Footprint and privacy | Shows whether the unit, access path, windows, entries, outdoor space, and neighbor privacy can work together. |
| Utilities, electrical, sewer, and water | Identifies routing, capacity, trenching, and coordination issues before a quote is treated as reliable. |
| Grading, drainage, and soil | Flags foundation, runoff, elevation, and site-prep issues before plans are locked. |
| Fire, life-safety, and construction access | Affects placement, staging, review, inspections, and whether equipment can reach the work area. |
| Intended use | Family use, long-term rental, privacy, storage, and accessibility goals can change layout and scope. |
These completed projects and construction photos show different parts of L Square's detached ADU work; every property still requires its own feasibility and scope review.
Rosemead project walkthrough is the primary completed detached example. The page states a finished 1,188 sq ft detached two-story ADU in Rosemead, with 3 bedrooms and 2 bathrooms, designed and built by L Square. It includes seven project images and a 48-second walkthrough.
Pasadena project walkthrough is secondary completed detached proof. This finished 700 sq ft detached ADU in Pasadena was designed and built by L Square, with six project images and a 56-second walkthrough.
ADU foundation article is construction-process proof, not completed-project proof. The linked article documents this project's Orange County detached ADU slab sequence: forms and plumbing, base/barrier/sand, pre-pour, pour, and finished slab. The displayed photo shows a construction stage, not a completed ADU. Foundation details vary with the approved plans, soils or geotechnical conditions, structural requirements, jurisdiction, and inspector.
State law establishes minimum detached ADU protections, while the responsible local agency and property conditions determine the usable size, height, placement and design path. For an Orange County address, use the official city resources below together with the state sources in this page’s rules section; Los Angeles properties require the correct City, County or independent-city review path.
Get a free, no-pressure quote from a licensed Orange County design-build team — and a plan drawn around your lot.