







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 Castaic
A garage conversion in Castaic typically runs between $85,000 and $160,000 for a full dwelling unit with a bathroom and kitchenette, before permit fees. The job usually takes 10 to 14 weeks from permit submittal to final inspection, assuming the HOA and County reviews don’t stall each other. Fielding ADU Builders handles the whole sequence – drawings, permit submittal, HOA packet, framing, mechanicals, finishes – under one written price. Call (361) 315-4177 for a free estimate and a line-by-line scope you can actually read.
Why Fielding ADU Builders Is Castaic’s Preferred Garage Conversion Contractor Company

Our crew has pulled permits and passed inspections on garage conversions throughout Castaic – off Hasley Canyon Road, in the Ridge, Kennedy Drive, and Hidden Lake Drive – and we know what the County plan checkers flag most often. That matters more than a vague claim about quality. When a Castaic homeowner asks us to convert a garage, we show up knowing which unincorporated LA County building & safety office will review the plans, what the inspectors want to see at each phase, and how to keep an HOA architectural committee from derailing a schedule.
We lead with a written price before any work starts. That price covers the scope from the first page of drawings to the final inspection sign-off, and the number you approve on day one is the number on the final invoice. If something fails in the workmanship, our 365-Day Done Right Promise says we return and correct it at no charge. No fine print, no renegotiation at the door. Reed Calloway runs our operation, and his name is on the guarantee.
Castaic homeowners call us because they’ve already been through a remodel that missed the schedule or moved the price mid-job. We don’t run our business that way. The Garrison Code is how we operate: show up in the window, price in writing, build by the book, leave it clean, stand behind it for a year.
Garage Conversion Contractor Work We Do in Castaic
We convert attached garages into bedrooms, home offices, in-law suites, and rental apartments. We convert detached garages into backyard ADUs with separate addresses and their own utility meters. Every project starts the same way: we walk the garage, check the slab, the roof structure, the electrical panel, the sewer line path, and the HOA rules if there are any, then we write the scope and price. No handshake estimates we’ll “firm up later.” Our Garage Conversion Contractor team handles framing through finishes, including the permits and the inspections in between.
Garage Apartment Conversion in Castaic

Garage Apartment Conversion in Castaic means turning a garage into a fully self-contained dwelling – a bedroom, a bathroom, a kitchenette, and its own entrance – often on an unincorporated lot where the County, not the City of Santa Clarita, has jurisdiction. A Castaic homeowner typically needs this when a parent moves in, an adult child returns, or a rental unit makes sense on a hillside property where a detached ADU would fight the grade.
A well-scoped garage apartment conversion in Castaic runs $110,000 to $160,000 before permit fees. That figure assumes the garage has a sound slab, the electrical service can handle a new subpanel, and the sewer line is accessible. Prefab walls from Cover or Dvele can trim framing time by three or four weeks on a tight lot, and conventional framing works better when an HOA demands a specific exterior material.
Attached Garage Apartment Conversion
An attached garage conversion shares walls and roof with the main house, which cuts foundation and roofing costs but raises the stakes on soundproofing and fire separation. The County requires a one-hour fire-rated separation between the garage apartment and the main dwelling, which affects the wall assembly and the door between the two spaces.
Detached Garage Apartment Conversion
A detached garage conversion is usually quieter to build – the crew doesn’t work through the main house – but it brings its own costs: a longer utility trench, a dedicated foundation check, and sometimes a new address assignment from the County. In Castaic’s unincorporated areas, a detached garage apartment is often classified as a full ADU, which changes the permit path.
Garage Conversion Permit in Castaic
Garage Conversion Permit in Castaic is a dual-track process in most of this community. If your property sits in unincorporated Los Angeles County territory – which covers much of Castaic – you need a Los Angeles County building permit, not a City of Santa Clarita permit. If your home is in an HOA tract like Hasley Canyon, you also need HOA architectural approval before the exterior design gets locked.
A Castaic garage conversion permit package includes architectural drawings, structural calculations for the new wall and any header work, Title 24 energy calculations, and a site plan showing setbacks from property lines. County plan check on a garage conversion typically runs 4 to 8 weeks. HOA review can add 2 to 6 weeks on top of that if the committee meets monthly. Fielding ADU Builders sequences both tracks side by side so the calendar doesn’t stall.
Unincorporated LA County Permitting
In unincorporated County territory near Castaic, a garage conversion is almost always a full building permit with plan check, not a same-day over-the-counter permit. The County reviews the project for structural safety, fire separation, egress, energy compliance, and zoning. Expect an inspection at foundation or slab, framing, electrical rough, plumbing rough, insulation, and final.
HOA Architectural Approval
An HOA in tracts like Hasley Canyon typically reviews exterior modifications – siding material, paint color, window style, and any street-facing changes – separate from the building permit. Getting the HOA packet submitted early is the single biggest schedule lever on a Castaic garage conversion, because many HOA committees only meet once a month.
Trusted Brands We Service in Castaic
We install and finish garage apartments using current prefab and panelized systems, including Cover, Dvele, and Boxabl where the site and budget fit. We also build conventional stick-frame with James Hardie siding when an HOA’s design rules dictate specific exterior materials. We don’t stock local parts for these platforms at a Castaic warehouse – the systems are factory-built – but we do stage deliveries to the site so the framing crew doesn’t wait on a truck.
Common Garage Conversion Contractor Problems We See in Castaic Homes
- Unpermitted starts. A homeowner starts converting a Castaic garage without a County permit, then tries to sell or refinance the house. The unpermitted work has to be exposed and re-inspected before it can be legalized, which often costs more than the original conversion.
- Skipped HOA review. In tracts like Hasley Canyon, the County permit gets pulled but the HOA was never notified, so the exterior siding and window style get flagged after framing. The HOA then demands material changes that force a partial re-build.
- Under-scoped pricing. A garage conversion gets priced as a cosmetic makeover – drywall, paint, flooring – when the actual job is a full dwelling unit with electrical service upgrade, new egress, insulation, HVAC, and a kitchen and bath rough-in.
- Slab surprises. Castaic garages built in the 1970s and 1980s often have slabs with no vapor barrier and minimal rebar, which means a conversion to living space needs a slab moisture test and often a new leveling pour before framing.
Pricing for Garage Conversion Contractor in Castaic, CA
A straight garage-to-living-space conversion in Castaic – drywall, flooring, electrical, one room – runs $85,000 to $120,000 before permit fees. A full garage apartment with a bathroom and kitchenette runs $110,000 to $160,000. The swing depends on the slab condition, the electrical panel capacity, the HOA’s exterior material rules, and the sewer line distance. Permit fees for a garage conversion in unincorporated Los Angeles County territory generally add $4,000 to $7,000 to the job, depending on the scope and the review. We give every Castaic homeowner a written line-by-line price before any work starts, and that price holds. Call (361) 315-4177 for a free estimate.
We Also Serve Cities Near Castaic
Fielding ADU Builders runs garage conversion projects in Castaic and across the surrounding Santa Clarita Valley, including Valencia, Stevenson Ranch, Santa Clarita, and Newhall. If your property sits in one of these cities, the same written-price-first policy and 365-Day Done Right Promise apply. Call (361) 315-4177 to schedule a walkthrough.
Serving Castaic, CA - Our Local Coverage Area
We’re based in the Castaic 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 Castaic

If your Castaic property sits in unincorporated Los Angeles County, you need a County building permit, not a City of Santa Clarita permit. Many Castaic homes – especially in hillside and canyon tracts like Hasley Canyon and the areas around the Ridge – fall under County jurisdiction. Check your property’s address or call us at (361) 315-4177 and we’ll confirm the jurisdiction before you spend a dollar on drawings.
An HOA in a tract like Hasley Canyon typically adds 2 to 6 weeks to a garage conversion timeline, on top of the County permit review. The HOA reviews exterior changes – siding, paint, windows – and may only meet monthly, so a missed deadline pushes the schedule back a full month. We submit the HOA packet and the County permit drawings at the same time to keep the two tracks moving.
The four biggest cost drivers are the slab condition, the electrical service size, the sewer line path, and any HOA exterior rules. A garage slab with no moisture barrier needs a new pour or an overlay. A 100-amp panel usually needs a service upgrade for a full apartment. A long sewer run to a public line costs more than a short one. And an HOA that demands specific siding or window styles can add several thousand dollars. An exact quote is free – call (361) 315-4177.
In unincorporated Los Angeles County, a garage conversion is inspected at slab or foundation, framing, electrical rough, plumbing rough, insulation, and final. There may also be a sewer inspection if the plumbing run is new. Each inspection has to pass before the next phase starts, and our crew coordinates the schedule so you aren’t waiting on the inspector.
The price changes only if the scope changes – for example, if the slab fails a moisture test, the HOA rejects the siding material, or you decide to add a bathroom mid-build. Our written price from day one covers the scope we agreed on, and any change gets priced in writing before the crew proceeds. No renegotiations at the door. Call (361) 315-4177 to talk through your garage conversion and get a written estimate that holds.
Get Your Castaic Garage Conversion Scoped and Priced Right
Much of Castaic’s housing stock sits in unincorporated Los Angeles County territory and in HOA-governed tracts like Hasley Canyon, so garage conversions here often need both a County building permit and separate HOA architectural approval – a dual-track review that doesn’t exist in many nearby incorporated cities. We know that path because we’ve walked it repeatedly. Our crew recently converted an attached two-car garage into a one-bedroom garage apartment off Hasley Canyon Road, framing the slab-to-ceiling layout, running a new subpanel, and finishing the exterior in James Hardie lap siding to satisfy the HOA’s color and material rules. The homeowner’s biggest sticking point wasn’t the build – it was coordinating the County inspection schedule with the HOA’s architectural review submittal, so we sequenced the permit drawings and the HOA packet side by side before anyone picked up a nail gun.
If you’re planning a garage conversion in Castaic, start with a free walkthrough and a written scope. Reed Calloway and the Fielding ADU Builders team will measure, check the slab and the panel, explain the permit path for your specific street, and hand you a printed price before any work starts. Call (361) 315-4177 to schedule your free estimate.
Written by Reed Calloway, Owner at Fielding ADU Builders, serving Castaic and the Santa Clarita Valley with garage conversions, ADUs, and Castaic Room Addition Contractor services.



