New Detached ADU in Tarzana - Design, Permits and Build Under One Contract

Fast, Reliable New Detached ADU Across Tarzana

A new detached ADU in Tarzana typically runs $320,000-$580,000 all-in, from permit set through final inspection, with custom builds at the higher end and prefab or modular systems landing closer to the middle. Most Tarzana projects clear plan check in 4-6 months and finish construction in 6-10 months, depending on whether your parcel sits in the flats or the hillside fringe. Call (747) 322-4648 to schedule your free estimate - every project gets a written price before any work starts, per Haven Standard Clause 1.

Call (747) 322-4648

We’re the team behind New Detached ADU projects across the San Fernando Valley, and we know Tarzana’s two faces well: the broad R1 lots south of Ventura Boulevard where a 1,200-square-foot unit fits comfortably within setbacks, and the southern hillside parcels where LA’s Very High Fire Hazard Severity Zone changes everything about what you can build and what it costs. Our crews serve Tarzana locally, with scheduling coordinated from our Los Angeles office. We’ve designed, permitted, and built over 900 ADUs since 2015, and the permit set - not the sales pitch - is what we lead with.

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

Tarzana homeowners don’t hire us because we’re nearby. They hire us because we document what we find, put the price in writing before a shovel hits dirt, and show up with a permit set that actually passes plan check. Our 365-Day Done Right Promise is in writing before the project starts - not a handshake after the fact.

We carry a strong local reputation across Tarzana’s 91356 zip, with verified reviews from homeowners in the Ventura Boulevard flats, the hillside streets off Reseda Boulevard, and the Briar Summit area. Clients mention the same things: the photo record they receive after every site visit, the written scope that doesn’t change once signed, and the live person who answers when they call. No voicemail queue. No callback that never comes.

Response time to Tarzana is same-week for initial site visits. We know the local conditions that slow other projects: aging Orangeburg sewer laterals common in 1950s-1970s ranch homes, original 100-amp panels that won’t carry a second dwelling, and the LA Fire Department’s WUI review that can add weeks to hillside permits if your designer doesn’t front-load the fire-resistant spec. We front-load it.

Our license number appears on every page. Our crews are background-checked and uniformed. And our Free Second Opinion stands if you’ve already got a written estimate in hand - we’ll tell you exactly where the scope is thin and where the pricing is optimistic.

Our New Detached ADU Services in Tarzana

Custom Built ADU

Custom builds give Tarzana homeowners full control over layout, finish, and siting - critical on irregular hillside lots where a box won’t fit and WUI compliance is non-negotiable. A custom detached ADU in Tarzana typically runs $380,000-$580,000 all-in. We produce the full permit set in-house, handle LA Department of Building and Safety plan check, and build to the drawings we signed. One contract. One written price. No designer-builder blame gap.

Prefab ADU Installation

Prefab systems from Abodu, Cover, and Plant Prefab cut site time dramatically - often 3-4 months from foundation pour to certificate of occupancy - but only if the spec matches Tarzana’s conditions. We specify coastal-grade hardware and sealed assemblies even for Valley sites because Tarzana’s UV exposure and Santa Ana wind cycles destroy inland-spec fasteners and joints within five years. Prefab detached ADUs in Tarzana typically land at $320,000-$450,000 all-in, including site prep, foundation, utility tie-ins, and the module itself. We coordinate the manufacturer, the crane, and the finish work under the same single contract.

Modular ADU

Modular construction - Dvele and Mighty Buildings are the systems we specify most - offers factory precision with site-built flexibility. For Tarzana’s larger R1 lots, modular ADUs scale cleanly to 800-1,200 square feet. The factory build happens concurrent with foundation and utility work, compressing overall timeline by 20-30%. Modular detached ADUs in Tarzana run $340,000-$480,000. We handle the state-certified modular approval process and the local LADBS site inspection as one workflow, not two competing schedules.

Studio ADU & 1-Bed/2-Bed Configurations

Studio ADUs - 350-450 square feet - fit well on Tarzana’s narrower lots or as backyard additions where setback limits pinch. One-bedroom units at 500-700 square feet and two-bedroom units at 800-1,000 square feet match the rental demand we see near Ventura Boulevard and the Tarzana Recreation Center. Every configuration gets the same permit-set rigor: Title 24 energy calculations, structural calcs for the Santa Ana wind load, and - on hillside parcels - the fire-resistant assembly documentation LAFD requires.

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Trusted Brands We Service in Tarzana

We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, Plant Prefab, and James Hardie - all within the same single contract that covers design, permitting, and construction. For Tarzana’s hillside WUI parcels, we default to James Hardie ignition-resistant siding and Class A roofing assemblies because we’ve seen standard vinyl and composite siding fail plan check at LAFD review. We don’t stock parts in a warehouse; we specify the right material for the specific parcel, source it with lead time built in, and coordinate delivery to avoid the job-site delays that kill schedules. Every brand we name appears in the written scope, with model numbers, before you sign.

Common New Detached ADU Problems We See in Tarzana Homes

• Coastal-grade fasteners corrode in Valley heat. Roofing fasteners and railings specified for mild coastal climates fail within three to five years in Tarzana’s 100-108°F summers and Santa Ana wind exposure. We specify hot-dip galvanized or stainless hardware with marine-grade finishes - the “coastal spec” that costs 15-20% more upfront and saves $8,000-$15,000 in replacement labor within a decade.
• Standard vents and siding trigger WUI rejection on hillside parcels. A detached ADU on Briar Summit or Tarzana’s southern fringe built with standard eave vents, wood siding, and Class B roofing will fail LAFD plan check. We flag the Very High Fire Hazard Severity Zone at preliminary research, not mid-permit, and spec ember-resistant enclosed vents, ignition-resistant siding, and Class A roofing from the first permit set.
• Unsealed paver joints and untreated fence posts loosen early. Tarzana’s dry heat and intense UV degrade standard concrete paver joints and untreated wood posts. We specify polymeric sand with sealant and hot-dip galvanized or stainless post hardware - details that add $800-$1,500 to a typical hardscape package and prevent the $3,000-$5,000 reset that follows failure.
• Aging electrical and sewer infrastructure stalls permits. Original 100-amp service and clay or Orangeburg sewer laterals - standard in Tarzana’s 1950s-1970s housing stock - won’t support a second dwelling. We evaluate both during preliminary site work and include replacement in the written scope if needed, so the City of LA doesn’t hold your certificate of occupancy hostage.

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 Tarzana neighbors in Encino, Sherman Oaks, Northridge, and Van Nuys. Each city carries its own plan-check quirks, hillside zones, and housing-stock patterns - we adjust the permit set and spec accordingly, never paste the same package across zip codes. If you’re comparing ADU potential across multiple properties, we’ll walk each site and give you a written price for each.

FAQs - New Detached ADU in Tarzana