Designing, permitting, and building detached ADUs, garage conversions, and Junior ADUs across the City of Los Angeles — San Fernando Valley, Westside, Eastside, Hollywood, and hillside. LADBS permits handled in-house. CSLB License #972213.
Hillstar Construction is a licensed Los Angeles ADU contractor. We've built detached ADUs, garage-conversion ADUs, above-garage units, and Junior ADUs (JADUs) for LA homeowners across the San Fernando Valley (Woodland Hills, Encino, Sherman Oaks, Studio City, Tarzana, Van Nuys, North Hollywood), the Westside (Mar Vista, Palms, West LA, Mid-City), the Eastside (Silver Lake, Echo Park, Highland Park, Eagle Rock, Atwater Village), Hollywood and the Hollywood Hills, and the hillside neighborhoods of Mount Washington, Los Feliz, and Sunland-Tujunga. Our office is on Ventura Boulevard in Woodland Hills — we've walked into the LADBS Valley branch office for our own projects more times than we can count.
Every LA City ADU project starts with a free on-site consultation, a clear written scope, and a straight answer about what your lot can actually support under LADBS, the LA Baseline Hillside Ordinance, HPOZ, and Protected Tree rules where they apply.
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An ADU inside the City of Los Angeles is not the same project as an ADU in Calabasas, Beverly Hills, or Pasadena. The permit authority is different (LADBS, not an independent city building department), the overlays are different (the LA Baseline Hillside Ordinance, not a local hillside rule), historic review runs through LA City's HPOZ system (not a city-specific Landmark Commission), and the protected-tree ordinance is species-specific (oak, sycamore, walnut, bay laurel) rather than lot-scale.
What also makes LA City different: the size. The city spans 469 square miles and almost every residential zoning category. A contractor who only works in one pocket of LA misses what an ADU on a flat R1 Mar Vista lot does not need — but a hillside-overlay lot in Laurel Canyon absolutely does. We scope every LA City ADU from the lot out: zoning, overlay, HPOZ, protected trees, fire zone, transit proximity for parking waiver, and the LADBS ADU Standard Plan options that might apply.
When a detached ADU isn't realistic for a given LA parcel — because of BHO grading, HPOZ review, a protected tree, or a tight envelope — a home addition or scoped home remodel is sometimes the cleaner path.
ADU rules are set by California state law plus the Los Angeles Municipal Code (LAMC). The baseline rules below apply to virtually every LA City lot. The specific envelope on your property depends on zoning, Baseline Hillside Ordinance status, HPOZ designation, protected-tree inventory, and fire-zone classification — which is what the first site visit covers.
State law requires Los Angeles to allow a detached ADU of at least 850 square feet for a studio or one-bedroom, or at least 1,000 square feet for two or more bedrooms. LA permits detached ADUs up to 1,200 square feet. Attached ADUs and garage conversions follow the same state minimums. The full 1,200 square feet is usually achievable on flat R1 Valley and Westside lots; hillside, HPOZ, and protected-tree parcels may support a smaller footprint.
State law limits required side and rear setbacks to no more than four feet for a new detached or attached ADU. No setback is required where you convert an existing garage to an ADU in its existing footprint.
ADU permits in the City of Los Angeles are issued through LADBS, coordinating with LA City Planning on zoning and LADWP on utility service. State law requires LADBS to determine application completeness within 15 business days and approve or deny a complete ADU application within 60 days. LADBS also runs the ADU Standard Plan Program — a library of pre-approved ADU plans that short-circuit much of plan check and can cut permitting weeks from the schedule where the plan fits the lot. The Los Angeles permit guide covers the broader LADBS flow.
The LA Baseline Hillside Ordinance (BHO) applies to parcels in designated Hillside Areas — a large footprint covering the Hollywood Hills, parts of the Santa Monica Mountains inside LA city limits, Mount Washington, Silver Lake and Echo Park hills, Eagle Rock foothills, Sunland-Tujunga, and hillside portions of Woodland Hills, Encino, and Sherman Oaks. BHO adds height, grading, and design provisions on top of standard ADU rules.
LA's HPOZ system covers designated historic districts — Angelino Heights, Vinegar Hill, Spaulding Square, West Adams Terrace, Highland Park, Jefferson Park, and others. Exterior work on HPOZ parcels typically requires Certificate of Appropriateness review under the district's Preservation Plan. The ADU design needs to respond to that plan.
The LA Protected Tree Ordinance covers Coast Live Oak and Valley Oak, Western Sycamore, California Black Walnut, and California Bay Laurel at 4 inches diameter and above. An ADU sited in the root-protection zone of a protected tree can require a Tree Report and a tree-protection plan, or a shift in the building envelope.
Hillside portions of LA City inside a Very High Fire Hazard Severity Zone are treated as Wildland-Urban Interface (WUI) under Chapter 7A of the California Building Code — ignition-resistant siding and soffits, dual-pane tempered or multi-pane glazing, ember-resistant vents, Class A roof assembly, and defensible-space compliance.
State law waives ADU parking requirements on any lot within a half-mile walking distance of public transit — a threshold that covers much of LA given Metro's rail network (Red, Purple, Expo, A, Crenshaw) and major bus corridors including the Orange/G Line busway. Where parking is required, it's limited to one space per unit or bedroom, tandem on an existing driveway allowed.
LA City is too big for one ADU recipe. The right build for a flat R1 Mar Vista lot is not the right build for a Laurel Canyon hillside parcel, an Angelino Heights HPOZ bungalow, or a Woodland Hills foothill estate. Here's how we match ADU type to neighborhood context in practice:
Detached new-build ADUs dominate the Valley. Flat lots in Woodland Hills, Encino, Sherman Oaks, Studio City, Tarzana, and Valley Village frequently support the full 1,200 square-foot envelope, with LADBS Standard Plans available on many lots. Hillside-overlay pockets south of Ventura Boulevard along the Santa Monica Mountains trigger BHO review.
Mar Vista, Palms, West LA, Mid-City, and Sawtelle have tighter R1 and R2 lots, but Metro's Expo Line and the Purple Line extension put a large share of parcels inside the half-mile transit waiver for ADU parking — often unlocking a detached or above-garage unit that would otherwise lose yard to replacement parking.
Silver Lake, Echo Park, Highland Park, Eagle Rock, and Atwater Village have a high proportion of lots with original detached garages — excellent garage-conversion candidates — and a high concentration of HPOZ-designated blocks where Certificate of Appropriateness review is the governing constraint. Sensitive garage conversions often pass HPOZ review more cleanly than new detached builds.
Hollywood Hills, Los Feliz, Laurel Canyon, and the broader hillside streets sit inside the Baseline Hillside Ordinance and, frequently, a Very High Fire Hazard Severity Zone. These projects are more design-intensive — BHO grading, Chapter 7A fire-zone materials — but they remain buildable on most qualifying lots, and ADU values on these blocks are high.
On HPOZ parcels where exterior expansion is constrained, on protected-tree lots that limit the detached envelope, on tight R1 Westside lots, or where a broader home remodeling project is already underway, a Junior ADU (JADU) — up to 500 square feet carved from the primary home — is often the cleanest path. JADUs continue to have owner-occupancy requirements under state law.
A realistic LA City ADU timeline from first site visit to certificate of occupancy is roughly 6 to 12 months for a standard flat-lot build. BHO hillside review, HPOZ Certificate of Appropriateness review, Chapter 7A detailing, and protected-tree plans add time where they apply. LADBS Standard Plans shorten time where they fit the lot. Construction itself runs 3 to 6 months for most detached builds once ground is broken.
Cost depends on ADU type, finishes, site conditions, BHO requirements, HPOZ detailing, and Chapter 7A materials where applicable. Our cost and ROI guide for building an ADU in Los Angeles lays out the numbers. What we commit to on every LA City project is a written scope, a clear price, no surprise change orders unless construction uncovers something that genuinely requires one, and direct access to your project manager from kickoff through final LADBS inspection.
The full ADU construction process — site evaluation, design, LADBS submission, build, final inspection — is covered step-by-step in our construction guide.
Hillstar was great! We did a garage conversion and Lior was the best. He helped us plan every detail.
— Jeffrey Rhodes, January 2019Lior was such a pleasure to work with for our guest house remodel. He was so easy to get in touch with, incredibly responsive and finished the job early.
— Amy Christine, February 2019Almost every single-family Los Angeles lot qualifies. California state law (Government Code §65852.2) requires LA to allow at least one ADU on single-family residential lots, and LA permits additional ADUs on many multi-family lots. What changes per lot is the type and size of ADU that fits — not whether you can build one. On the same block you may find an R1 flat lot that supports a 1,200-square-foot detached new-build and a hillside-overlay lot next door that only supports a smaller garage conversion. We confirm exact zoning, Baseline Hillside Ordinance status, HPOZ designation, protected-tree inventory, and fire-zone classification at the first site visit.
Yes. ADU permits in the City of Los Angeles are issued through the Los Angeles Department of Building and Safety (LADBS), coordinating with LA City Planning on zoning and LADWP on utility service. State law requires LADBS to determine application completeness within 15 business days and approve or deny a complete ADU application within 60 days. LADBS also runs the ADU Standard Plan Program — a library of pre-approved ADU plans that short-circuit much of plan check and can cut permitting weeks from the schedule. We submit through LADBS end to end, use Standard Plans where they fit the lot, and manage plan-check corrections, utility coordination, and final inspection from first drawing to certificate of occupancy.
It can. The LA Baseline Hillside Ordinance (BHO) applies to parcels in designated Hillside Areas — a large footprint covering portions of the Santa Monica Mountains within LA city limits, the Hollywood Hills, Mount Washington, Silver Lake and Echo Park hills, Eagle Rock foothills, Sunland-Tujunga, and the hillside portions of Woodland Hills, Encino, Sherman Oaks, and the San Fernando Valley. BHO adds height, grading, and design provisions on top of standard ADU rules. Hillside ADUs take longer to design and permit but remain buildable on most qualifying lots.
Yes. LA City Historic Preservation Overlay Zones (HPOZs) — including Angelino Heights, Vinegar Hill, Spaulding Square, West Adams Terrace, Highland Park, Jefferson Park, and others — do not block ADUs, but exterior work typically requires Certificate of Appropriateness review. The ADU design needs to respond to the HPOZ district's Preservation Plan — roof form, siding, window type, setback, and how the unit reads from the street and the alley. A sensitive garage conversion often moves through HPOZ review more cleanly than a new detached build. We design HPOZ ADUs to pass Certificate of Appropriateness review the first time.
They can. The LA City Protected Tree Ordinance covers four native species — Coast Live Oak and Valley Oak, Western Sycamore, California Black Walnut, and California Bay Laurel — at 4 inches diameter and above. Siting an ADU in the root-protection zone of a protected tree can require a Tree Report, a tree-protection plan, or a shift in the building envelope. This is common on older hillside parcels and parts of the Valley. We inventory protected trees at the first site visit and locate the ADU to respect their root-protection zones from the first drawing.
California state law requires LA to allow a detached ADU of at least 850 square feet (studio or one-bedroom) or 1,000 square feet (two or more bedrooms). The City of Los Angeles permits detached ADUs up to 1,200 square feet. On most flat R1 Valley and Westside parcels the full 1,200 square feet is achievable. Hillside Area lots, HPOZ parcels, protected-tree lots, and tight buildable envelopes may support a smaller footprint, which we scope at the first site visit and confirm at LADBS plan submittal.
Tap your LA neighborhood for local zoning, hillside, HPOZ, and protected-tree details:
Encino · Sherman Oaks · Studio City · Tarzana · Valley Village · Woodland Hills
Different city, different building department. If your property is in one of these neighboring cities, permitting goes through their own department — not LADBS:
