Detached ADU
A separate building on the lot. Consider siting, construction access, privacy and new utility routes. The most independent physical arrangement often means more site work.
Accessory dwelling units · Greater Los Angeles
ADU construction shaped by your property.
KB Remodeling builds around the real conditions of the site, not a one-size-fits-all floor plan. A detached unit, attached unit, garage conversion or junior ADU brings different structure, utility, access and review questions; the scope must account for the chosen unit’s site work, building systems, review sequence, construction access and closeout.
Discuss your ADU site
01
Four paths, different starting conditions
These describe common configurations, not a promise that any particular parcel qualifies. A JADU is a distinct category with its own state rules, not simply a small detached ADU.
Attached ADU
Connected to the primary home. Shared walls and existing services may affect design, fire separation and construction while the house is occupied.
Garage conversion
Reuse an existing garage shell only after reviewing foundation, height, openings, moisture, utilities and prior permits. Existing walls do not necessarily mean simple work.
Junior ADU (JADU)
A smaller unit formed within qualifying space of a single-family residence. State JADU rules differ from ADU rules; confirm the applicable standards and owner-occupancy conditions with the reviewing agency.
A good fit when
- You want a second residential unit and are ready to test a specific parcel.
- Access, existing buildings and utility routing can be studied before choosing the unit type.
- The main home's occupancy and the new unit's intended use are part of the brief.
Compare another route when
- Changing the primary home rather than adding a unit may call for whole-home remodeling.
- Reusing a garage and building a new detached shell require different investigations; neither is automatically simpler.
What changes with the ADU path
A scope framework, not a finding that a particular parcel is eligible or a guarantee about required permits.
| Construction path | Physical work to test | Decision record |
|---|---|---|
| New detached unit | Footprint, ground work, site access, new envelope and utility routes | Site plan, service assumptions and consultant questions |
| Attached unit | Connection to the home, openings, shared services and occupied access | Interface drawings and household protection assumptions |
| Garage conversion | Existing slab, shell, moisture, openings and service upgrades | Condition findings and retain-or-rebuild scope |
| JADU | Qualifying space within the residence and applicable distinct standards | Existing-plan review and agency questions |
02
Compare the practical tradeoffs
The right path depends on the actual property; these are questions to investigate, not guaranteed outcomes.
| Path | Potential advantage | Early constraint to test |
|---|---|---|
| Detached | Separation and privacy | New building footprint, access and utility runs |
| Attached | Relationship to existing home | Shared-wall design and household disruption |
| Garage conversion | Existing structure may be reused | Condition, height and services of the shell |
| JADU | Uses qualifying space within the residence | Different state rules and occupancy conditions |
03
A parcel-specific feasibility conversation
Who reviews this address?
City limits, unincorporated county areas and special review zones can change the agency and applicable standards. Start with jurisdiction, not a city name on the mailing address.
Where can people and trades get in?
Measure usable access, existing structures, easements and possible construction staging; note privacy and the route from street to unit.
How will utilities reach it?
Trace water, sewer and electrical paths and investigate capacity, meters or upgrades with the appropriate providers before treating them as solved.
The ADU decision and build sequence
- 01
Site review
Gather survey or plans, existing permits and utility information; flag any unknown boundaries or conditions.
- 02
Feasibility and concept
Compare unit types against site geometry, access, services and the intended living arrangement.
- 03
Design and approvals
Coordinate design and needed consultants, submit plans to the responsible agency and respond to corrections.
- 04
Construction and closeout
Plan site protection, utilities and trade sequencing; complete applicable inspections and collect closeout records.
Questions to bring
- Is the property inside city limits or county jurisdiction?
- What existing structures and permits are on file?
- Where would construction equipment enter?
- Where are existing water, sewer and electrical services?
- Will the main home remain occupied?
What a feasibility review should clarify
- Candidate unit type and unresolved site constraints
- Survey, engineering and utility questions
- Approving agency and permit steps to verify
- Concept layout and access assumptions
- Scope items still unknown before a construction proposal
Planning resources for your ADU
Start with California guidance and the building department responsible for your property. Requirements depend on the site and jurisdiction.
ADU questions
What types of ADU can be built?
Detached ADUs, attached ADUs, conversions of existing space such as a garage, and junior ADUs of up to 500 square feet inside the main house. Which type fits depends on the lot, access and existing structures.
How long does an ADU permit take?
Under state law, once an ADU application is complete the local agency must approve or deny it within 60 days. Design, consultant work and corrections before that point, and construction after, are separate.
What affects the cost of an ADU?
Type and size, foundation and soil conditions, utility connections and distance to existing lines, site access for equipment, fire-separation needs and finishes. Utility and agency fees are set by each provider.
Is a garage conversion automatically easier than a new ADU?
No. Reusing a shell may help, but foundation, height, waterproofing, utilities and permit history can change the amount of work.
When can we choose a design?
After the reviewing jurisdiction and key site conditions are known. An attractive plan alone cannot establish parcel eligibility or utility capacity.
Does a JADU follow the same rules as a detached ADU?
No. California treats JADUs as a separate category with distinct location and occupancy requirements. Verify the current state and local rules for the property.
Explore an ADU path
Prepare your project brief
Keep the property questions, priorities and your own figures together before reaching out.
Open the planning studio ↗KB Remodeling · Greater Los Angeles