New Detached ADU in Tarzana - One Fixed Price, Permits Handled

Fast, Reliable New Detached ADU Across Tarzana

A new detached ADU in Tarzana typically runs $220,000-$380,000 all-in, from permit set through final inspection, with most projects clearing LADBS in 8-14 months depending on hillside zoning and electrical conditions. We serve Tarzana from our Los Angeles office, and our crews know the difference between a flat-lot ranch off Ventura Boulevard and a hillside parcel on the north slope where fire-zone rules and soils reports add mandatory steps. Call (424) 551-7706 to schedule your free estimate - we’ll walk your lot, check your panel, and give you a written price before any work starts.

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Why Ellery ADU Studio Los Angeles Is Tarzana’s Preferred New Detached ADU Company

We’ve designed, permitted, and built ADUs across Tarzana since 2015 - the year California’s ADU laws opened up - and our permit sets are built for LADBS plan checkers, not just for show. Our Tarzana clients receive a documented photo record on every visit, a written price locked at signing under Haven Standard Clause 1, and the 365-Day Done Right Promise in writing before construction begins.

Dispatch and scheduling run from our Los Angeles office, but the crews on your Tarzana property are local and know the Valley’s permit rhythm. We’ve handled the 100-amp panel upgrades on Tampa Avenue ranches, the hillside fire-zone packages off Corbin Avenue, and the oversized RE-11 lots where a full 1,200 sq ft detached ADU fits without a variance. A live person answers our line 24/7 - no voicemail queue, no callback that doesn’t materialize.

Nadia Ellery, who leads our studio, reviews every Tarzana permit set personally before it hits LADBS. That matters here, because Tarzana’s mid-century housing stock throws the same three conditions at nearly every project: outdated electrical, aging waterproofing, and framing that doesn’t meet current shear-wall standards. We’ve seen enough of them to price the allowances correctly upfront.

Our New Detached ADU Services in Tarzana

Custom Built ADU

Custom built ADUs in Tarzana run $260,000-$380,000 all-in and give you full control over layout, materials, and finish level. On the ranch homes that dominate Tarzana - single-story, 1950s to 1970s, often 10,000-15,000 sq ft lots - a custom detached unit lets you match the existing roofline, siding, and window rhythm so the ADU reads as original to the property. We design the permit set in-house, build from our own drawings, and hold one contract for the entire project. No designer-builder gap.

On hillside parcels, custom build is often the only practical path. The slope, the retaining wall, and the fire-resistive envelope requirements don’t play well with standard prefab dimensions. We engineer for the specific Tarzana hillside, price the soils report and geological review into the contract, and coordinate with LADBS’s Hillside Section from day one.

Prefab ADU Installation

Prefab ADU installation in Tarzana typically costs $220,000-$310,000, including site prep, foundation, utility tie-ins, and LADBS final. We specify and coordinate prefab systems from Abodu, Cover, and Dvele - brands whose modules we’ve already run through LA’s plan check process. The advantage is factory precision and a compressed construction schedule on site. The constraint is your lot: flat parcels with clear crane access work best. Hillside lots with tight setbacks or utility conflicts usually push back toward custom.

We handle the brand coordination under our single contract, so if the module arrives with a finish mismatch or a dimension tolerance issue, we don’t point at the factory - we fix it. That’s Haven Standard Clause 5: no surprises, no scope creep, no door-side upsells.

Modular ADU

Modular ADUs in Tarzana fall in the $240,000-$330,000 range and occupy the middle ground between full custom and prefab: factory-built structural modules, finished on site with your chosen cladding and fixtures. We work with modular systems that have cleared California’s factory inspection program, which LADBS accepts in lieu of some field inspections. On Tarzana’s larger RE-15 lots north of the boulevard, modular can make sense when you want faster occupancy but need the footprint flexibility that prefab doesn’t offer.

Studio ADU

Studio ADUs in Tarzana run $180,000-$260,000 and suit homeowners who want rental income or guest space without the full bedroom-and-kitchen investment. On a typical 10,000 sq ft Tarzana lot, a 400-500 sq ft studio detached ADU clears setbacks easily and still leaves room for the main house, driveway, and required landscaping. We size the mini-split for Tarzana’s summer reality - 100°F+ days are standard, not exceptional - and spec the insulation package to pass Title 24 without the upgrade gymnastics that cheaper bids skip.

1-Bed & 2-Bed ADU

One-bedroom detached ADUs in Tarzana typically cost $220,000-$300,000; two-bedroom units run $280,000-$380,000. These are the formats that turn an ADU into a real rental asset or long-term family housing. On Tarzana’s RE-11 and RE-15 zoned lots, a 750-1,000 sq ft 2-bedroom detached unit is often achievable by-right, with no variance needed. We confirm that at the initial site visit, check the specific setback and lot-coverage math against your parcel map, and write the finding into your estimate so there’s no permit denial surprise six months in.

Trusted Brands We Service in Tarzana

We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, and James Hardie - all within the same single contract that covers design, permitting, and construction. For Tarzana’s climate and fire-zone conditions, we often lean on James Hardie fiber-cement cladding for the exterior envelope: it meets LA’s Very High Fire Hazard Severity Zone requirements without the maintenance cycle of wood siding, and it holds up to the Valley’s thermal expansion stress better than vinyl. When a Tarzana client chooses a Cover or Dvele module, we verify the factory spec against LADBS’s current fire-resistive material checklist before the order goes in, not after it arrives.

Common New Detached ADU Problems We See in Tarzana Homes

• 100-amp electrical service triggers a mandatory panel upgrade. Nearly every Tarzana ranch built between 1950 and 1975 carries 100-amp service, and LADBS plan checkers now condition detached ADU permits on upgrading to 200 amps. We price this as a line item in every Tarzana estimate, not as a mid-project change order.
• Hillside parcels north of Ventura Boulevard hit fire-zone and soils requirements. The Very High Fire Hazard Severity Zone and Hillside Area Construction Regulations add fire-resistive material standards, extended setbacks, and often a soils or geological report. Flat-lot Valley assumptions don’t apply here, and we flag the distinction at the first site visit.
• Failed waterproofing and undersized framing surface during tie-in work. Opening walls on a 60-year-old Tarzana ranch for the ADU utility connection regularly reveals dry rot, termite damage, or original 2×4 framing that doesn’t meet current shear-wall standards. We build a re-framing and waterproofing allowance into every contract, with a written trigger price if the damage exceeds the allowance.
• Title 24 energy compliance forces mini-split and insulation upgrades. Tarzana’s 100°F+ summer heat load means garage conversions and detached ADUs alike need properly sized HVAC and attic insulation that older homes never had. We model the energy compliance in the permit set, not as an afterthought that kills the project at plan check.

Pricing for New Detached ADU in Tarzana, CA

We Also Serve Cities Near Tarzana

Our crews work throughout the central and east San Fernando Valley, including New Detached ADU projects in Encino, Sherman Oaks, Van Nuys, and Studio City. Each city has its own LADBS plan check quirks and neighborhood housing stock - Encino’s larger estate lots, Sherman Oaks’s denser infill conditions, Van Nuys’s broader zoning mix - and we adjust the permit set and pricing accordingly. The same written-price guarantee and 365-Day Done Right Promise apply across every project.

FAQs - New Detached ADU in Tarzana