







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Garage Conversion Contractor Across Simi Valley
Looking for a garage conversion contractor in Simi Valley who will give you a real number before work starts? A full garage conversion to living space in Simi Valley typically runs $85,000 to $165,000 depending on whether you’re adding a bathroom, upgrading the slab, and how much structural correction the existing garage needs. Our crew knows Simi Valley’s hillside lots, its aging tract housing, and the permit office on Tapo Canyon Road. Call (831) 230-7250 and you’ll reach a live person who can talk through your specific garage, not a voicemail.
We’re Lodgewick ADU Ventura, the ADU company of the Kingswell family. We specialize in garage conversions, accessory dwelling units, and home additions across Simi Valley, from the flats off Los Angeles Avenue to the canyon neighborhoods east of Yosemite. The Kingswell Way means a written price first, a real arrival window, a clean job site, and a guarantee in writing on every project.
Why Simi Valley Homeowners Choose Lodgewick ADU Ventura for Garage Conversions

Simi Valley homeowners call us after they’ve been burned by a bid that changed at the door or a contractor who stopped answering the phone. Our answer is simple. The Kingswell Guarantee puts four commitments in writing before any work begins: a written price, a defined arrival window, a clean job site, and a written guarantee on the finished conversion. If something isn’t right within 365 days, we come back and make it right. That’s the 365-Day Done Right Promise, and it’s in writing on every project we do in Simi Valley.
Russ Delmar leads Lodgewick ADU Ventura. He’s spent years working on garage conversions throughout Ventura County, including the specific challenges that come with Simi Valley’s older tract homes. When Russ walks a garage on a street near Santa Susana Knolls, he’s checking the slab thickness, the footing depth, the rear yard setback, and whether the existing structure can carry a second story. That’s the difference between a bid that holds and one that falls apart during rough inspection.
Our technicians are background-checked and uniformed. You’ll know exactly who’s on your property and when they’re arriving. Our scheduling is coordinated from the brand’s Los Angeles office, with local crews serving Simi Valley every week. And every call, including at 2 a.m. when you can’t sleep thinking about your budget, is answered by a live person. Not a chatbot. Not a voicemail loop.
Garage Conversion ADU in Simi Valley
A Garage Conversion ADU in Simi Valley means converting an existing attached or detached garage into a legal accessory dwelling unit with its own kitchen, bathroom, and private entrance. In Simi Valley this typically runs $110,000 to $165,000 for a one-bedroom unit with a full bath, though a basic studio conversion without major slab work can come in closer to $85,000. The cost driver isn’t the square footage – it’s what’s under the slab and inside the walls. Most Simi Valley garages built before 1990 were poured at 3 to 4 inches with no rebar, which fails current shear inspection requirements.
Slab and footing corrections
Simi Valley sits on a mix of alluvial soil and hillside terrain. Garages on the flat grid streets around Sinaloa Road often sit on thin post-war slabs. Garages in the canyons or on lots sloping toward the Arroyo Simi frequently have settling issues we find only after pulling the permit and starting demo. When the slab doesn’t meet spec, we pour a thickened-edge footing or new stem wall before framing begins – and because we’re a Garage Conversion Contractor that writes the price first, any structural correction gets discussed before a single nail is driven.
Attached garage conversion specifics
An attached conversion shares a fire-rated wall with the house, which means Simi Valley inspectors will look for proper separation and, in most cases, a sealed combustion HVAC unit. That’s a cost many flatland contractors outside Simi Valley never budget for. We do. The same goes for relocating the water heater and any gas line that runs through the garage ceiling.
Garage Apartment Conversion in Simi Valley

A Garage Apartment Conversion in Simi Valley is a detached garage turned into a rentable, self-contained unit – essentially a small house on your existing lot, which is exactly what the name Lodgewick means. Detached conversions in Simi Valley run $95,000 to $155,000 depending on the condition of the structure, whether we need to bring utilities from the main house, and the level of finish. A converted garage apartment with a bedroom, bath, and kitchenette on a flat lot near Big Sky will cost less than the same unit on a hillside where we’re correcting drainage and shoring the downhill side.
Simi Valley’s zoning code allows a 10-foot rear yard setback reduction for garage conversions when the original garage already encroaches into the required yard. That’s a significant local provision – if your garage sits close to the rear property line, which many 1960s and 1970s tract homes do, you can often preserve the full garage footprint in the conversion. Contractors who don’t do regular Simi Valley work miss this provision and tell homeowners the conversion won’t fit. It usually will.
Detached garage conversion timeline
Once permits are issued, a typical detached garage apartment conversion in Simi Valley takes 9 to 14 weeks. That includes the slab correction, framing, rough MEP, drywall, finish work, and final inspection with the Ventura County Building and Safety office serving Simi Valley. Weather plays a small role – Simi Valley’s dry, hot summers are actually ideal for exterior work and concrete curing, which means crews can keep to schedule better than they can in coastal cities with marine layer delays.
Utility and drainage considerations
Detached garages in Simi Valley rarely have water, sewer, or adequate electrical service. Running a new sewer lateral from the main house to a detached garage on a sloped lot can add $8,000 to $15,000 to the project, especially if we’re trenching through your driveway. We sleeve any aging utility lines we encounter, like the corroded water main our crew found under a driveway off Katherine Road – they sleeved it before inspection, which is why the inspection passed the first time.
Trusted Brands We Service in Simi Valley
We work hands-on with leading ADU brands and materials, including Abodu and Cover for prefabricated garage conversion kits, and James Hardie for fiber cement siding that holds up to Simi Valley’s hot, dry summers without warping or fading. For homeowners who want a faster build, a Cover prefab ADU can shave several weeks off a detached conversion, and we handle the site work, slab correction, and utility connections in Simi Valley around their factory-built panels. We match the system to your lot, budget, and the specific demands of your hillside or flatland site, not the other way around.
Common Garage Conversion Contractor Problems We See in Simi Valley Homes
- Thin slabs without rebar. Pre-1980 garages in Simi Valley’s older tracts, especially around the Sinaloa area, were often poured 3 to 4 inches thick with no steel reinforcement. That slab will crack under the point loads of interior walls and a new bathroom, and it’ll fail shear inspection. We check this before quoting, which is why our numbers hold.
- Hillside drainage issues. Canyon lots and any property sloping toward the Arroyo Simi collect water against the garage foundation. We see rusted base plates, efflorescence on stem walls, and slabs that have settled on the downhill side. A proper conversion needs a drainage correction and sometimes a new stem wall, not just a cosmetic fix.
- Missing the rear yard setback provision. Simi Valley allows garage conversions to keep encroaching into a required rear yard, provided the original garage already encroached. Homeowners who get a bid from a contractor unfamiliar with local code sometimes hear the conversion won’t pass. It will, when the plans are drawn by someone who knows the provision.
- Unplanned HVAC and fireplace costs. Attached garages share walls with the house, and Simi Valley inspectors require sealed combustion HVAC in most converted attached garages. That means relocating or replacing a furnace or water heater, which can add $4,000 to $9,000. We put that in the written price, not as a change order after demo starts.
Pricing for Garage Conversion Contractor in Simi Valley, CA
A garage conversion in Simi Valley is a significant investment, and you deserve a number you can plan around. Here’s what we see in the current Simi Valley market:
- Basic studio conversion (no kitchen, existing slab in good shape): $75,000 – $95,000
- One-bedroom ADU with bathroom and kitchenette: $110,000 – $145,000
- Detached garage apartment with full utilities: $95,000 – $155,000
- Structural slab correction where required: $8,000 – $20,000 added, identified before work starts
The factors that move the number: slab condition, hillside drainage work, whether we need to trench a sewer line through the driveway, whether HVAC relocation is required, and finish level on the interior. We walk your garage, check the slab, look at your rear yard setback, and then give you a written price before any work begins. No price changes at the door. Call (831) 230-7250 to schedule a free estimate.
We Also Serve Cities Near Simi Valley
Our Simi Valley crews work throughout the surrounding communities, including Moorpark, Newbury Park, Fillmore, and Somis. If you’re in one of those cities and want the same written-price-before-work approach with a Simi Valley level of hillside and slab expertise, call (831) 230-7250. We’ll get you on the schedule.
Serving Simi Valley, CA - Our Local Coverage Area
We’re based in the Simi Valley 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 About Garage Conversion Contractor in Simi Valley
A legal ADU in Simi Valley requires a minimum interior ceiling height of 7 feet. Many older garages in Simi Valley’s 1950s and 1960s tracts sit right at or just below that mark after you account for floor leveling and insulation. If your garage ceiling is 6 feet 10 inches, we need to raise the roof or drop the floor, and that changes the price. Call (831) 230-7250 and we’ll measure it during the free estimate.
Yes, for a legal garage conversion ADU in Simi Valley, the garage door comes out and gets replaced with a properly insulated, shear-rated wall system that matches the existing exterior. The opening becomes either a window, a French door, or a blank wall depending on your floor plan. If you want to keep a roll-up door for a workshop feel, that’s not a legal bedroom or ADU condition, and it will fail inspection.
After permit issuance, a typical attached garage conversion ADU in Simi Valley takes 8 to 12 weeks, while a detached unit with new utilities takes 9 to 14 weeks. The variance comes from how much slab work is needed and whether you’re using a prefab system like Abodu or Cover, which can compress framing time. For an exact timeline on your specific garage, call (831) 230-7250.
Sometimes. If the slab is at least 4 inches thick with rebar and shows no significant cracking or settling, it can often be built over. But most pre-1980 Simi Valley garage slabs are 3 to 4 inches with no rebar, and those fail shear inspection for an ADU. We check the slab during the estimate and tell you before quoting whether you’ll need a thickened-edge correction. That’s the only way to give you a written price that holds.
In Simi Valley, the Simi Valley Unified School District levies a school impact fee on residential construction, including detached ADUs over a certain square footage threshold. Attached garage conversions that stay under 750 square feet are typically exempt, but a detached garage apartment of 800 square feet or more will likely trigger the fee. During your free estimate we’ll tell you if your project falls under the threshold and, if not, exactly what the fee will add to the total. Call (831) 230-7250 to get your number in writing.
Written by Russ Delmar, Owner at Lodgewick ADU Ventura, serving Simi Valley with garage conversions, ADUs, and home additions under The Kingswell Guarantee.




