Fast, Reliable Garage Conversion ADU Across West Hills
Garage conversion ADUs in West Hills typically run $95,000-$165,000 all-in, from measured drawings through final LADBS inspection, with most projects completing in 6-10 months. Because a large share of West Hills parcels fall within LA’s Very High Fire Hazard Severity Zone, your garage conversion must meet WUI ignition-resistant construction standards even when the existing walls stay standing, adding material cost and plan-check scrutiny that non-fire-zone neighbors simply don’t face.
We’re Ellery ADU Studio, a design-build practice founded in 2015, and our Garage Conversion ADU team serves West Hills from our Los Angeles office. Nadia Ellery and our crew know the difference between a Woodland Hills lot on flat valley floor and a West Hills parcel tucked against the Santa Susana foothills where the VHFHSZ line cuts through. That local knowledge shows up in your permit set before we submit to LADBS, not after the first correction cycle.
Call (820) 444-6584 to schedule your free estimate. Every project starts with a written price under Haven Standard Clause 1, and we offer a Free Second Opinion on any written estimate already in your hands.
Why Ellery ADU Studio Simi Valley Is West Hills’s Preferred Garage Conversion ADU Company
We’ve designed, permitted, and built more than 900 ADUs since 2015, and a growing share of them sit in West Hills neighborhoods like Orcutt, Hidden Lake, and the streets bordering Bell Canyon. These homeowners came to us after learning that their 1960s ranch’s original 100-amp panel and cloth-wrapped wiring wouldn’t pass modern load calculations, or after another contractor missed their VHFHSZ status and got flagged on first plan check.
Our crews are background-checked, uniformed, and licensed, with our license number on every page. Dispatch and scheduling are coordinated from our Los Angeles office, but the crew that opens your garage wall knows West Hills: the Santa Ana wind patterns that drive rain against north-facing garage doors, the 100°F summer days that make Title 24 energy compliance a real engineering exercise, and the LADBS plan checkers who now expect ignition-resistant construction callouts on every West Hills submittal.
Under The Haven Standard, you receive a written price before any work starts, a documented photo record on every visit, and our 365-Day Done Right Promise backed in writing. A live person answers calls 24/7. No voicemail queue. No callback that doesn’t materialize.
Our Garage Conversion ADU Services in West Hills
Attached Garage Conversion
Attached garage conversions are the most common ADU type we build in West Hills, and they’re also where the most surprises hide. Your garage shares a wall with the house, which means the existing electrical panel, sewer lateral, and foundation all become part of the scope. On a 1968 ranch in the Orcutt neighborhood of West Hills, our crew opened the attached garage wall and found cloth-wrapped wiring, a 100-amp panel already at capacity, and a sill plate that had rotted from a failed slope - plus the parcel’s VHFHSZ status meant ember-resistant vents and ignition-resistant cladding had to be spec’d before we framed. We priced the panel upgrade, sill replacement, and WUI details as written allowances, got the homeowner’s signed approval before demolition, and passed LADBS plan check on the first submittal after front-loading the fire-zone callouts.
Because a large share of West Hills parcels sit inside LA’s Very High Fire Hazard Severity Zone, a garage conversion ADU here must meet WUI ignition-resistant standards (Class A roofing, ember-resistant vents, ignition-resistant cladding) even when the garage walls stay standing - so an attached garage conversion in West Hills can cost more in fire-rated details than a full detached build on a non-VHFHSZ lot in Woodland Hills. We confirm fire-zone status before drafting a single sheet.
Detached Garage Conversion
West Hills lots run generous by LA standards, often a quarter-acre or more, so detached garages are common along streets like Roscoe Boulevard and Fallbrook Avenue. Converting one to an ADU gives you more flexibility on utilities - separate electric meter, separate sewer connection - but it also means running new trenching across a yard that may carry mature oak roots or undocumented irrigation lines. We map the full utility path in the permit set, not discover it with a backhoe.
Garage Partition & Bathroom Add
Not every West Hills homeowner wants a full ADU. Some need a guest suite with bath, a home office with powder room, or a rental unit that keeps the garage bay for storage. We partition the space, add the wet wall, and engineer the plumbing tie-in to your existing sewer lateral - which, on older West Hills homes, may need replacement before the city issues certificate of occupancy. We price that possibility as a written allowance before we cut concrete.
Garage JADU
A Junior ADU (JADU) lives inside your existing garage footprint, shares your house’s kitchen and bathroom or gets its own efficiency kitchen, and must be owner-occupied. For West Hills homeowners who want rental income without the full ADU investment, a garage JADU caps out at 500 square feet and can share utilities. The catch: your existing 100-amp panel and original sewer lateral still need to handle the load, and VHFHSZ rules still apply to exterior modifications. We model both constraints in the initial permit set.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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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 Coordinate in West Hills
Ellery ADU Studio specifies and coordinates prefab and modular systems from Dvele, Mighty Buildings, and Plant Prefab within the same single contract that covers your design, permitting, and construction. For West Hills homeowners considering a hybrid approach - say, a Plant Prefab unit dropped onto a new foundation while the existing garage becomes the JADU - we engineer the site prep, utility tie-ins, and LADBS coordination as one scope at one written price. No designer pointing at the builder, no builder blaming the drawings.
Common Garage Conversion ADU Problems We See in West Hills Homes
- 100-amp panel and cloth wiring fail load calculations. The 1950s-1970s ranch homes that dominate West Hills commonly carry original electrical systems that cannot handle the ADU’s HVAC, kitchen appliances, and lighting load. We find this on inspection, price the service upgrade as a written allowance, and get your signed approval before touching the panel.
- VHFHSZ status missed in initial drafting. Contractors who skip pulling the VHFHSZ map before submitting ADU plans to LADBS routinely get flagged on first plan check for missing ignition-resistant construction callouts. We confirm fire-zone status on every West Hills parcel before drafting a single sheet, front-loading the WUI details into the permit set.
- Garage slab and sill plate compromised by decades of weathering. West Hills sits at the valley’s western inlet, where Santa Ana wind-driven rain and 100°F temperature swings have already damaged original framing before walls are opened. Our inspection documents the condition; our contract includes a written allowance for sill replacement and slab remediation if needed.
- Title 24 energy calculations demand aggressive insulation and HVAC sizing. West Hills summer temperatures routinely top 100°F, so a garage conversion ADU needs robust attic insulation and high-efficiency mechanical systems to pass energy compliance. We run the calc during design, not during inspection, and spec equipment that handles the load without change orders.
Pricing for Garage Conversion ADU in West Hills, CA
Garage conversion ADUs in West Hills typically run $95,000-$165,000 all-in, drawings through final inspection. Attached garage conversions on VHFHSZ parcels trend toward the upper half of that range because of ignition-resistant cladding, ember-resistant vents, and Class A roofing requirements. Detached garage conversions on non-fire-zone lots can land lower, though new utility trenching may offset the savings.
What moves the number: panel and service upgrades ($8,000-$18,000), sewer lateral replacement ($6,000-$14,000), foundation repair or sill plate replacement ($4,000-$12,000), and WUI compliance details on VHFHSZ parcels ($5,000-$15,000). We price every line item in writing before work starts, per Haven Standard Clause 1. No call-for-a-quote. No scope creep.
Call (820) 444-6584 for your exact number. Estimates are free, and we offer a Free Second Opinion on any written estimate already in hand.
We Also Serve Cities Near West Hills
Our crews work throughout the west San Fernando Valley, including Garage Conversion ADU in West Hills and neighboring Canoga Park, Winnetka, Calabasas, and Chatsworth. Each city carries its own LADBS or LA County plan-check path, its own fire-zone mapping, and its own vintage housing stock. We adjust the permit set accordingly.
Serving West Hills, CA - Our Local Coverage Area
We’re based in the West 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 West Hills
Yes. If your parcel sits within LA’s Very High Fire Hazard Severity Zone, WUI standards apply to the entire ADU envelope, including existing walls that remain. That means ember-resistant vents, ignition-resistant exterior cladding, and Class A roofing must be specified even for a partial conversion. We pull the VHFHSZ map before drafting and front-load these callouts into the permit set to avoid a correction cycle at LADBS. Call (820) 444-6584 to confirm your parcel’s status and get a written quote.
Original 100-amp panels and cloth-wrapped wiring from the 1950s-1970s cannot handle the combined load of the main house plus an ADU’s HVAC, kitchen, and lighting. When we open the wall and find this, we document it with photos, price the upgrade as a written allowance under Haven Standard Clause 5 (No Surprises), and get your signed approval before touching the panel. Call (820) 444-6584 to schedule an inspection and written estimate.
The calc demands high-efficiency HVAC sized for extreme cooling loads, plus robust attic and wall insulation to reduce heat gain. In West Hills, we typically spec 16+ SEER mini-split systems and R-38 attic insulation minimum. We run the energy model during design, not after framing, and include the equipment in your written price. Call (820) 444-6584 for a project-specific calc and quote.
Often yes. Original sewer laterals in 1950s-1970s West Hills homes are frequently clay or cast iron with root intrusion or slope failure. The city will not issue certificate of occupancy if the ADU’s plumbing ties into a compromised lateral. We camera-inspect during our initial site visit, price replacement as a written allowance if needed, and coordinate the work before drywall. Call (820) 444-6584 to schedule an inspection and written estimate.
A JADU may share the house panel and water heater if the existing systems have adequate capacity, but in practice, most West Hills homes from the 1960s and 1970s do not. We model the actual load during design and give you a written price for either shared or separate utilities, with the decision locked at contract signing under Haven Standard Clause 5. Call (820) 444-6584 to review your specific system capacity and get a written quote.
Written by Nadia Ellery, Owner at Ellery ADU Studio, serving West Hills since 2015.