Fast, Reliable New Detached ADU Across San Fernando
A new detached ADU in San Fernando typically runs $220,000-$420,000 all-in, from the first site measure through final inspection, depending on whether you choose a custom stick-built structure, a prefab system, or a modular unit. We’re Ellery ADU Studio, and our crews serve San Fernando from our Los Angeles office, handling the full design-build sequence - drawings, permit set, construction, and utility tie-ins - under a single contract at a single written price. Call (661) 528-5298 to schedule your free estimate, or bring us any written estimate you already have for a Free Second Opinion.
Why Ellery ADU Studio Lancaster Is San Fernando’s Preferred New Detached ADU Company
We’ve designed, permitted, and built more than 900 ADUs since 2015, the year California’s ADU laws began their major shift. San Fernando properties represent a distinct subset of that work: small lots, post-WWII housing stock, and a permit counter that is not LADBS. Our familiarity with San Fernando’s Building & Safety Division saves our clients the re-submittal delays that catch contractors who assume LA City jurisdiction covers this 2.4-square-mile enclave.
Our San Fernando clients receive the same documentation we provide everywhere: a written price before any work starts (Haven Standard, Clause 1), a documented photo record on every site visit, and the 365-Day Done Right Promise in writing. If the finished ADU does not match the permitted drawings, we make it right. No designer-versus-builder blame gap exists here - the drawings and the construction are one contract, one accountable party.
A live person answers our phones 24/7. No voicemail queue, no callback that doesn’t materialize.
Our New Detached ADU Services in San Fernando
Custom Built ADU
Custom built ADUs in San Fernando typically run $280,000-$420,000 all-in. These are stick-framed structures designed to your lot’s specific constraints - setback variances, utility locations, and the grade changes common along the Maclay corridor and near Glenoaks Boulevard. We handle the full permit set through San Fernando’s Building & Safety Division, not LADBS, and we build in allowances for the electrical and structural upgrades these 1940s-1960s properties routinely need.
Prefab ADU Installation
Prefab ADU installation in San Fernando typically runs $220,000-$340,000, including foundation, utility tie-in, and finish work. We specify and coordinate systems from Abodu, Cover, and Dvele - brands whose panelized or fully prefabricated units we integrate under the same single contract. San Fernando’s narrow alley-accessed lots and tight side-yard clearances make crane access and module placement a site-specific puzzle; we survey for that in the design phase, not discover it on delivery day.
Modular ADU
Modular ADUs in San Fernando typically run $240,000-$360,000. These factory-built modules arrive near-complete and set on a permanent foundation. The advantage on San Fernando’s older lots is controlled construction time - less exposure to the 100°F+ inland Valley heat that can warp framing and delay exterior finish work. We coordinate with modular manufacturers to ensure the unit meets San Fernando’s specific ADU ordinance and Title 24 energy requirements before it leaves the factory.
Studio ADU
Studio ADUs in San Fernando typically run $220,000-$320,000. These compact detached units - usually 300-450 square feet - fit well on the small lots that dominate San Fernando’s post-WWII neighborhoods. The challenge here is not footprint but infrastructure: many of these properties have sub-100-amp electrical service and galvanized drain lines that cannot support an additional dwelling without upgrade. We identify this in the initial site assessment and write it into the contract as a line item, not a mid-project surprise.
1-Bed & 2-Bed ADU
One-bedroom detached ADUs in San Fernando typically run $260,000-$380,000; two-bedroom units run $320,000-$420,000. The jump in cost reflects not just square footage but the full kitchen, laundry, and separate HVAC zones that trigger additional Title 24 compliance. On San Fernando’s older bungalows, a 2-bed ADU often requires a main panel upgrade to 200 amps and a new sewer lateral - scope we flag and price upfront.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Fernando
We specify and coordinate prefab and modular systems from Abodu, Cover, Dvele, Mighty Buildings, and others - always within our single-contract design-build model. Our San Fernando clients benefit from our direct relationships with these manufacturers’ West Coast distribution networks, which means faster lead times on module delivery and replacement components. When a San Fernando project calls for site-built construction, we source James Hardie cladding and Tuff Shed utility structures through the same coordinated procurement system. Everything flows through one contract, one written price, one accountable team.
Common New Detached ADU Problems We See in San Fernando Homes
- Jurisdictional confusion with LADBS. San Fernando is an independent city completely encircled by Los Angeles, with its own Building & Safety Division and ADU ordinance. Contractors who submit plans to LADBS instead of San Fernando’s counter trigger costly re-submittal delays. We file directly with San Fernando’s plan checkers from day one.
- Title 24 energy compliance failures on garage conversions. San Fernando’s inland Valley location means regular 100°F+ summer days. Detached garage shells with thin walls, uninsulated concrete slabs, and former roll-up door openings almost always fail energy compliance without significant insulation build-out and a properly sized mini-split system. We engineer for this in the permit set.
- Unremediated 1971 Sylmar earthquake damage. San Fernando was the named epicenter of that earthquake. Many older detached garages still show cracked foundations, shifted mudsills, or deteriorated anchor bolts. We budget for structural repair discoveries that would be far less common a few miles west in Sherman Oaks or Van Nuys.
- Outdated electrical and plumbing infrastructure. The post-WWII bungalows that dominate San Fernando’s housing stock commonly have 60-100 amp service, cloth-wrapped wiring, and galvanized or cast-iron drain lines. These cannot support a second dwelling without upgrade. We identify this in our initial site assessment and write it into the contract.
Pricing for New Detached ADU in San Fernando, CA
New detached ADU pricing in San Fernando breaks down as follows:
| ADU Type | Typical All-In Range |
|---|---|
| Studio ADU (custom) | $220,000 - $320,000 |
| 1-Bedroom ADU | $260,000 - $380,000 |
| 2-Bedroom ADU | $320,000 - $420,000 |
| Prefab ADU (installed) | $220,000 - $340,000 |
| Modular ADU | $240,000 - $360,000 |
What moves the number: foundation condition (especially earthquake damage), electrical service capacity, sewer lateral capacity, and the extent of utility trenching required. San Fernando’s small lots often mean longer trench runs to the main house, which we measure and price before signing. Under Haven Standard Clause 5 (No Surprises), the scope is locked at signing; any discovery after demolition is priced in writing and approved before we proceed. Call (661) 528-5298 for your written estimate - they’re always free.
We Also Serve Cities Near San Fernando
Our crews work throughout the northern San Fernando Valley and Santa Clarita Valley, including San Fernando, Sylmar, Tujunga, Santa Clarita, and Stevenson Ranch. Each city has its own permit authority and ADU ordinance; we file correctly the first time. If you’re comparing options across these markets, our New Detached ADU hub page outlines our full design-build process and Haven Standard protections.
Serving San Fernando, CA - Our Local Coverage Area
We’re based in the San Fernando area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - New Detached ADU in San Fernando
They go to San Fernando’s own Building & Safety Division, not LADBS. San Fernando is an independent city of 2.4 square miles completely surrounded by Los Angeles, and it maintains separate plan checkers, inspectors, and ADU ordinances. Submitting to LADBS is a common and expensive mistake that triggers re-submittal and weeks of delay. We file directly with San Fernando’s counter on every project. Call (661) 528-5298 if you have plans in hand and want to verify the filing path.
These properties almost always need electrical, plumbing, and structural upgrades that newer homes don’t. Sub-100-amp service, galvanized drain lines, and stucco-over-wood framing require substantial work to meet current California ADU permitting thresholds. We identify these conditions in our initial site assessment and write them as line-item allowances in the contract, not as open-ended contingencies. Call (661) 528-5298 for a written estimate with allowances spelled out.
We inspect for it before demolition and write repair allowances into the contract. Cracked foundations, shifted mudsills, and deteriorated anchor bolts are field conditions we expect on San Fernando’s post-WWII stock, not exceptions. If we find damage after framing comes off, we pause work, photograph the condition, price the repair in writing, and require your approval before proceeding. This is Haven Standard protocol on every site. Call (661) 528-5298 to schedule an assessment.
No. San Fernando’s inland Valley climate - regular 100°F+ summer days - means thin garage walls, uninsulated concrete slabs, and former roll-up door openings fail energy compliance without significant modification. We engineer insulation build-out, proper air sealing, and a right-sized mini-split system into every garage conversion permit set. The compliance path is known and priced before construction starts. Call (661) 528-5298 for a free estimate.
We stop work, document with photos, price the repair in writing, and require your signed approval before touching anything. Our crew opened up a 1950s stucco-over-wood bungalow on Glenoaks Boulevard near the Maclay corridor to tie a new detached ADU into the main panel and uncovered a 100-amp service with cloth-wrapped wiring and a shifted mudsill from the 1971 Sylmar earthquake. We paused the job, priced the panel upgrade, reframed sill, and galvanized supply swap in writing, got sign-off before touching anything, and only then set the James Hardie-clad detached unit on its new slab. The client approved the change order in a day instead of discovering it mid-framing as a surprise invoice. That’s how we work on every San Fernando project. Call (661) 528-5298 to schedule your free estimate.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving San Fernando since 2015.