Fast, Reliable Garage Conversion ADU Across Granada Hills
A garage conversion ADU in Granada Hills typically runs $95,000-$165,000 all-in, from measured drawings through final LADBS inspection. Most attached garage conversions we handle in Granada Hills move from signed contract to permit in 8-12 weeks, though detached conversions or properties with post-1994 seismic work can add 3-6 weeks for engineering review. Call (747) 294-4817 to schedule your free estimate - we bring a written price, not a sales pitch.
We serve Granada Hills from our Los Angeles office, with crews who know the difference between a 1956 ranch on Balboa Boulevard and a post-Northridge rebuild near the Santa Susana foothills. That local knowledge matters because Granada Hills garage conversions hit complications that don’t show up in other San Fernando Valley cities - undocumented seismic repairs, fire-hazard zone cladding rules, and on northern lots, horse-keeping overlays that complicate setback calculations. Our Garage Conversion ADU team has navigated these specific LADBS requirements for Granada Hills properties since 2015.
Why Ellery ADU Studio Santa Clarita Is Granada Hills’s Preferred Garage Conversion ADU Company
Granada Hills homeowners find us after they’ve already talked to a designer who can’t build, or a contractor who can’t draw. We’re neither. Ellery ADU Studio operates as a single-contract design-build studio - the permit set, the construction documents, and the build itself are one scope at one written price, governed by The Haven Standard. No designer-builder blame gap, no change orders born from drawing errors.
We’ve designed, permitted, and built 900+ ADUs since 2015, every one with a written price before work started and a documented photo record when complete. That includes dozens of garage conversions in Granada Hills proper - from attached two-car garages on Knollwood Street to detached structures near O’Melveny Park. Our license number appears on every page; it’s verified, not claimed.
Nadia Ellery leads the studio, and our crews are background-checked, uniformed, and briefed on Granada Hills-specific conditions before they arrive. A live person answers calls 24/7. If you already have a written estimate in hand, we’ll give you a Free Second Opinion - no obligation, no pressure.
Our Garage Conversion ADU Services in Granada Hills

Attached Garage Conversion
Attached garage conversions are the most common ADU we permit in Granada Hills. The typical 400-500 sq ft two-car garage on a mid-century ranch converts to a one-bedroom, one-bath unit with kitchenette and separate entrance. In Granada Hills, these almost always trigger LADBS scrutiny of the shared wall and roof tie-in - especially if the original structure predates 1971 and lacks documented shear-panel nailing. We handle the structural calculations in-house, submit the permit set as a complete package, and price any seismic upgrade as a line item before demo, not after.

Detached Garage Conversion
Detached garages in Granada Hills often sit on generous lots - 8,000-12,000 sq ft is typical - which gives flexibility on setbacks and parking replacement. But detached conversions here carry a specific risk: the 1994 Northridge earthquake damaged or destroyed hundreds of detached garages in this ZIP code, and post-quake repairs were frequently done without permits. We pull the LADBS record before we quote. If the stem wall or cripple-wall bracing lacks documentation, we flag it early, engage a structural engineer, and price the fix in writing. No surprises at plan check.

Carport Conversion
Carport conversions in Granada Hills face a straightforward challenge - most carports lack foundations adequate for habitable space. The slab is often thin, un-reinforced, or sloped for drainage. We assess the existing condition, design a stem-wall or grade-beam foundation as needed, and include that scope in your written quote from day one. For carports near the Santa Susana foothills, we also verify fire-hazard zone status early; noncombustible cladding and ember-resistant vents add cost but are non-negotiable for LADBS sign-off.

Garage Partition & Bathroom Add
Some Granada Hills homeowners want to keep parking and add a studio - we partition the garage, insulate and finish one bay as a habitable unit, and add a bathroom with proper venting and drain tie-in. The 3-inch cast-iron drain lines common in 1950s-70s Granada Hills homes often can’t handle new fixtures without replacement or trenching to the main. We camera the line during pre-construction and price the drain work as a separate allowance, visible in your contract.

Garage JADU
A Junior ADU - under 500 sq ft, sharing utilities with the main house, no separate meter - can be the fastest path to rental income in Granada Hills. The JADU rules are stricter on owner-occupancy and exterior door requirements, but the permit timeline is typically shorter. We verify your lot qualifies under LA’s JADU ordinance, confirm the electrical panel has capacity, and deliver a permit set that meets LADBS standards without revision cycles.

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.
- 3
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 Granada Hills
Ellery ADU Studio specifies and coordinates prefab and modular systems from Cover, Dvele, and Mighty Buildings within the same single-contract framework we use for stick-built conversions. For Granada Hills properties in LA’s Very High Fire Hazard Severity Zone, we frequently specify James Hardie noncombustible cladding as part of the exterior package - it’s a material we know, stock locally, and can source without the lead times that stall other projects. Every brand choice is documented in the permit set and priced in your written quote before work begins.
Common Garage Conversion ADU Problems We See in Granada Hills Homes

- Undocumented seismic repairs from the 1994 Northridge earthquake. We regularly open garage walls in Granada Hills and find reworked stem walls or mismatched cripple-wall bracing with no permit on file. LADBS stops the permit until a structural engineer signs off. We pull records early and price the engineering scope before demo.
- Failed 3-inch cast-iron drain lines. The 1950s-70s housing stock in Granada Hills used cast-iron drains that corrode from the inside. New ADU fixtures overload them. We camera every drain during pre-construction and replace as needed, with the scope in your written contract.
- Slab-on-grade moisture intrusion. Garage floors in Granada Hills were rarely built with proper vapor barriers. Once we demo, efflorescence and spalling appear. We test for moisture, design a floating floor or epoxy seal system, and price it as a line item - not a mid-project surprise.
- Very High Fire Hazard Severity Zone cladding requirements. Properties near the Santa Susana foothills must use noncombustible exterior materials and ember-resistant vents. We verify zone status at the first site visit and specify compliant materials from the start, avoiding plan-check rejection.
Pricing for Garage Conversion ADU in Granada Hills, CA
Garage conversion ADUs in Granada Hills typically run $95,000-$165,000 all-in, drawings through final inspection. Attached conversions on straightforward slabs with no seismic complications trend toward the lower end. Detached conversions, properties requiring foundation work, or those with undocumented post-Northridge repairs move toward the higher end. Properties in the Very High Fire Hazard Severity Zone add $8,000-$15,000 for noncombustible cladding and vent upgrades.
| Scope Element | Typical Range in Granada Hills |
|---|---|
| Attached garage conversion, no seismic issues | $95,000-$125,000 |
| Detached garage conversion, standard foundation | $110,000-$145,000 |
| Seismic engineering + retrofit (undocumented repairs) | $12,000-$28,000 |
| Drain line replacement (cast-iron to ABS) | $4,500-$9,000 |
| Fire-hazard zone cladding upgrade | $8,000-$15,000 |
| Slab moisture remediation + floating floor | $3,500-$7,500 |
Every project is quoted with a written price before any work begins - Haven Standard, Clause 1. If we open walls and find conditions we couldn’t predict, we document with photos, price the fix in writing, and get your approval before we proceed. No door-side upsells. No scope creep. Call (747) 294-4817 for your free estimate.
We Also Serve Cities Near Granada Hills

Our crews work throughout the northern San Fernando Valley, including Garage Conversion ADU in Granada Hills and neighboring Mission Hills, San Fernando, Northridge, and Sylmar. Each city has its own LADBS district office quirks, and we know which ones require pre-submission meetings, which accept virtual plan check, and where the seismic review backlog sits. That local intelligence saves weeks on your permit timeline.
Serving Granada Hills, CA - Our Local Coverage Area
We’re based in the Granada Hills 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 - Garage Conversion ADU in Granada Hills

Not every garage conversion needs new seismic work, but many in Granada Hills need engineering verification of existing repairs. Because this area was in the maximum-destruction zone, undocumented post-quake structural changes are common - mismatched cripple-wall bracing, reworked stem walls, unpermitted shear-panel additions. LADBS will not issue an ADU permit without engineer sign-off if any of these are present. We pull LADBS records and inspect the structure during our pre-construction survey, then price any needed engineering scope in your written quote before demo begins. Call (747) 294-4817 for a free estimate.
The most common surprises are failed waterproofing on slab-on-grade floors, corroded 3-inch cast-iron drain lines, and undocumented structural modifications from the 1994 earthquake. Off a Granada Hills street near the Santa Susana foothills, we opened the walls of a 1962 attached two-car garage for a conversion and found the stem wall had been reworked after Northridge with no permit on file - LADBS wanted engineering sign-off before it would issue. We pulled the record, had a structural engineer detail the cripple-wall bracing, and priced the fix as a written change order before we touched a single stud. Because the lot sits in LA’s Very High Fire Hazard Severity Zone, we also swapped the exterior to James Hardie noncombustible cladding and ember-resistant vents so the sign-off wouldn’t come back a second time. Call (747) 294-4817 to schedule your site survey.
Yes, for properties near the Santa Susana foothills in northern Granada Hills. LA’s Very High Fire Hazard Severity Zone triggers Chapter 7A of the California Building Code, requiring noncombustible exterior cladding, ember-resistant vents, and specific eave and soffit details. These are not optional upgrades - LADBS will reject plans that don’t comply. We verify zone status at the first site visit, specify compliant materials from the start, and include the cladding package in your written quote. Call (747) 294-4817 for an exact assessment of your property.
They can. Parts of northern Granada Hills carry a horse-keeping overlay (Very Low II zoning), where lots often exceed 15,000-20,000 sq ft. That square footage gives exceptional ADU headroom under LA’s lot-coverage rules, but existing corrals, accessory barns, or unpermitted tack rooms can encroach on required setbacks and stall the ADU permit until resolved. We survey the full lot, identify conflicts with the parcel map, and work with LADBS to legalize or relocate encroachments before submitting the ADU plan set. Call (747) 294-4817 to review your lot’s specific conditions.
Opening walls for an ADU conversion triggers current code for everything exposed - electrical, plumbing, insulation, egress, and structural. In Granada Hills, this commonly means upgrading to AFCI/GFCI protection, adding shear-panel nailing where the garage shares a wall with the house, and bringing ventilation up to current standards. We inspect before we quote, photograph existing conditions, and write allowances into your contract for likely upgrades. Under Haven Standard Clause 5 (No Surprises), any condition we couldn’t predict is documented, priced in writing, and approved by you before we proceed. The scope is locked at signing. Call (747) 294-4817 for a written quote with allowances explained line by line.
Ready to convert your Granada Hills garage into a permitted, income-producing ADU? Call (747) 294-4817 to schedule your free estimate. We’ll bring a measuring tape, a camera, and a written price - not a sales binder.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving Granada Hills since 2015.