An ADU permit — not a room-addition permit — creates a second legal dwelling.
Attached ADU in Los Angeles — Adding a Unit to Your Existing Home
An attached ADU is new square footage built onto your existing home — sharing a wall, but with its own entrance, kitchen, bathroom, and, under a correctly filed permit, its own legal identity as a separate dwelling. We file it as an ADU from the first submission, under CSLB License #1071589.
CSLB #1071589Correct Permit ClassificationLicensed Since 2020
A Second Legal Dwelling
An Attached ADU Creates a Second Legal Dwelling — A Room Addition Does Not
An attached ADU is new square footage built directly onto your existing home.
It shares at least one wall with the primary structure. But it has its own entrance, its own kitchen, its own bathroom — and under a correctly filed permit, its own legal identity as a separate dwelling unit. That last part is what separates an attached accessory dwelling unit from a room addition. Both involve construction; both expand your home’s footprint. Only one creates a unit you can legally rent, legally occupy as a second household, or legally list on a certificate of occupancy. The distinction starts at the permit application — and it has to be right from the first submission.
The Right Permit Classification
Los Angeles Attached ADU Projects Start With the Right Permit Classification
Filing the wrong permit type costs more to fix than getting it right upfront. Here’s what many homeowners don’t realize: a room addition permit and an attached ADU permit are not interchangeable names for the same application. They follow different review tracks at LA DBS, carry different setback rules, trigger different inspection sequences, and produce completely different legal outcomes for your property.
A room addition permit creates additional square footage within your existing home. It does not establish a second dwelling unit. If you install a kitchen in that space and rent it, the unit is unpermitted as a residence — regardless of how finished the construction is. We file attached ADU projects under the correct classification from the start: the application identifies the project as an ADU, which is what produces a legal dwelling, a compliant inspection sequence, and the ability to rent once the certificate of occupancy is issued.
When An Application Comes Back
What I See When an Attached ADU Application Comes Back for Corrections
— Uzi Ezra, Founder & CEO, US LA Home Remodeling Inc
I reviewed a project last year where a homeowner had already started construction — they’d expanded the back of the house with new framing, a roof tie-in, and plumbing roughed in. The work looked solid. The problem was the permit application: it had been filed as a room addition, not an attached ADU. So they had a nearly complete unit with no legal path to being rented. The permit on record didn’t create a dwelling — it created square footage.
The correction process meant reviewing whether the existing permit could be amended or whether a new ADU application had to be filed in parallel; a LA DBS review of the fire wall condition — the shared wall has to meet a specific fire-resistance rating when the space functions as a separate dwelling, and it hadn’t been framed or finished to that standard because no one had designed for ADU use; and restarting the inspection sequence in certain phases. That homeowner spent money twice — once to build it, once to bring it into compliance.
“When I file an attached ADU permit, the application identifies the project as an ADU from page one — tie-in drawings, fire wall spec, separate entrance, and metering all in the initial submission. LA DBS reviews it as an ADU. The certificate of occupancy creates a legal unit.”
Filed Correctly, First
Your Attached ADU Permit Is Filed Correctly Before Any Framing Begins
The permit classification is confirmed before design starts, not discovered after construction. Every homeowner asks some version of the same question — how do I know the permit will hold up? The answer is straightforward: we confirm the correct permit type before we commission any drawings.
CSLB License #1071589 authorizes structural additions to existing residences and direct permit filing with LA DBS as the contractor of record. When the application goes in, it identifies the project as an attached ADU — not a room addition, not an addition with a kitchenette. The difference shows up at every stage: how LA DBS routes the review, which inspector signs off on which phase, and what document gets issued at the end. The certificate of occupancy for a permitted ADU is what makes the unit legally occupiable. We don’t correct that problem later — we prevent it at submission.
Our Standards
Our Standards for Attached ADU Construction in Los Angeles
Every attached ADU we build in Greater Los Angeles meets the same structural, fire-separation, and utility standards.
- Structural tie-in — new framing connects to the existing foundation; shear-wall requirements in the engineering drawings
- Fire wall compliance — the shared wall framed, insulated, and finished to code on both sides, not just the ADU side
- Separate entrance — the ADU has its own exterior entry, not the primary home’s front door
- Separate electrical metering — LADWP coordination for an independent meter when the unit is rented
- Permit type accuracy — filed as an ADU, so inspections, setbacks, and the certificate of occupancy reflect a legal dwelling
How We Build
How We Build an Attached ADU in Los Angeles
Three stages, run in the permit’s inspection order — nothing finished before the rough inspections pass.
Diagnostics
Before any design, we review the property’s existing conditions — the foundation system the new framing will tie into, the current roof structure at the point of attachment, and the setback conditions on the specific lot. We also confirm the permit classification upfront: your address, zoning designation, and existing structure type determine which LA DBS review track applies, so the drawings are designed to the right standard from the start.
Implementation
Construction follows the permit’s inspection schedule: demolition and site prep, then foundation work at the addition footprint, then new framing tied into the existing structure per the engineer’s drawings. The fire wall is framed and finished before rough systems; electrical, plumbing, and mechanical rough-ins each require sign-off before walls close. The separate entrance is established in this phase. Finish work comes last.
Post-Service Testing
Final inspections with LA DBS cover every trade system — electrical, plumbing, mechanical — plus the structural tie-in and fire wall, each signed off independently. The final building inspection closes the permit, and LA DBS issues the certificate of occupancy: legal confirmation that the unit is a permitted dwelling, following the title permanently. If separate metering was coordinated, meter installation is scheduled after the permit closes.
Areas We Serve
Attached ADU Construction Across Greater Los Angeles
We work across the San Fernando Valley, the Westside, the South Bay, the San Gabriel Valley, and surrounding LA County neighborhoods. Our Tarzana office gives us direct access to both City of LA DBS district offices and unincorporated LA County DPW for properties outside city limits.
San Fernando ValleyWestside LASouth BaySan Gabriel ValleyTarzanaCity of Los AngelesUnincorporated LA CountyLos Angeles County
Ready to Start?
Build a Legal Attached ADU — Start With the Right Permit
An attached ADU adds a legal dwelling to your property — with a certificate of occupancy that holds up at rental, resale, and refinancing. That outcome starts with one thing: filing the correct permit type before construction begins. Tell us your property address and project scope, and we’ll outline what your attached ADU will require.
1-800-508-0259 · info@uslaremodeling.com · 5530 Corbin Ave, Tarzana, CA 91356
FAQ
Frequently Asked Questions About Attached ADUs in Los Angeles
What’s the difference between an attached ADU and a room addition?
Both add square footage that shares a wall with your home, but only an ADU permit creates a second legal dwelling — one you can rent, occupy as a separate household, or list on a certificate of occupancy. A room addition permit adds space to your existing home; install a kitchen in it and rent it, and the unit is unpermitted as a residence regardless of how finished the construction is. The distinction starts at the permit application.
Can I convert a room addition that’s already built into an ADU?
Sometimes — but it’s the expensive path. The existing permit has to be reviewed for whether it can be amended or whether a new ADU application must be filed in parallel; the shared fire wall has to be reviewed against the required fire-resistance rating; and certain inspections restart because rough sign-offs happened under a different permit type. Filing as an ADU from the first submission avoids paying twice.
What is the fire wall requirement on an attached ADU?
The shared wall between the ADU and the primary residence must meet a specific fire-resistance rating under California Building Code — framed, insulated, and finished to that standard on both sides of the wall, not just the ADU side. We include the fire wall specification in the engineering drawings and build it before rough systems go in.
Does an attached ADU need a separate electrical meter?
When the unit will be rented to a separate tenant, we coordinate with LADWP for an independent meter so the ADU can be billed separately. Meter installation is scheduled during the final phase, after the permit closes.
What makes an attached ADU legally rentable?
The certificate of occupancy issued for a permitted ADU. Without it, the space is finished construction — not a legal home. The C of O is what holds up at rental, resale, and refinancing, and it follows the property’s title record permanently.