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 Altadena
A garage conversion in Altadena typically runs $110,000 to $180,000 for a full apartment-grade build with a bathroom and kitchen, while a simpler bedroom-and-office conversion without plumbing lands between $65,000 and $95,000. Permit fees, fire-rated upgrades required in the Very High Fire Hazard Severity Zone, and site prep add another $8,000 to $20,000 depending on your parcel. The work usually takes 12 to 20 weeks from permit submittal to final inspection, not the 6 weeks some contractors quote before they’ve seen the fire zone requirements.
We know Altadena’s lots, its older slab foundations, and the county review process that applies here. If you’re weighing a garage conversion against a full ADU, call (361) 315-4177 and we’ll walk the site, check the slab, and hand you a written price before any work starts.
Why Fielding ADU Builders Is Altadena’s Preferred Garage Conversion Contractor
Fielding ADU Builders works inside Altadena because the site conditions here reward a contractor who reads the parcel before quoting it. Many garages in Altadena sit on slabs poured decades ago, some with no rebar and inconsistent thickness. The county’s fire hazard designation also means any garage conversion gets reviewed for ember-resistant venting and fire-rated assemblies. Contractors who do not open with that conversation set up a bad price on day one. We open with the slab, the setbacks, and the fire zone.
We are an independently owned member of the Garrison Partners family, and we’ve built to The Garrison Standard since 2006. That standard is short: show up in the window, put the price in writing, do the work by the book, leave the job clean, and stand behind it for a full year. Reed Calloway runs our Garage Conversion Contractor team, and every crew member on your Altadena site is background-checked and arrives in uniform.
When you call, a live person answers. No voicemail queue. No callback in three days. And the price you approve on day one is the price on the final invoice, because we write it down before a single nail is driven.
Garage Apartment Conversion in Altadena
Garage Apartment Conversion in Altadena means converting an existing garage shell into a self-contained living unit with its own bathroom, kitchen, and separate entrance, typically 400 to 600 square feet. In the flats around Lake Avenue and east toward Eaton Canyon, these projects run $120,000 to $180,000 before permit fees. The price depends heavily on whether the existing slab can carry a wet wall, whether the garage roof framing allows insulation and drywall, and whether the county’s fire hazard review adds ember-resistant vents and fire-rated siding upgrades.
Detached Garage Conversions East of Lake
Detached garages off streets like Santa Rosa Avenue and Mariposa Street often have good access for concrete and framing crews, but the slabs are usually old and sometimes out of level. We check for slab thickness before we quote, because a bathroom pan set on a cracked or thin slab will fail later. That check is part of the written price, not an add-on after the fact.
Garage to Bedroom and Living Space Without a Kitchen
A garage-to-bedroom conversion that adds a bathroom but no kitchen typically lands between $80,000 and $115,000 in Altadena. The cheaper build path skips the second wet wall, which saves on slab saw-cutting, plumbing, and the fire-rated separation details around a cooking appliance. Some homeowners start with the bedroom and bath, then add a kitchenette later. If that’s the plan, we frame the future kitchen wall now so the second phase doesn’t double back on drywall and electrical.
Garage Conversion Permit in Altadena
Garage Conversion Permit in Altadena is the county permit that changes a garage’s legal use from vehicle storage to habitable space. It requires architectural plans, structural calculations, a Title 24 energy report, and in most of Altadena a fire hazard review that looks at exterior siding, venting, and the roof assembly. County plan check often takes 8 to 14 weeks here, and hillside or WUI addenda can stretch that to 4 or 5 months. We submit the full plan set and track the review ourselves, so you aren’t calling a plan checker cold.
Fire-Rated Assembly and Ember-Resistant Venting
Because most of Altadena sits inside the county-designated Very High Fire Hazard Severity Zone, the county asks for fire-rated walls where the converted garage meets the property line, plus ember-resistant vents at the gable ends and under the eaves. This is not a cosmetic upgrade. It affects the framing details, the siding choice, and the venting schedule. We price it from the first walkthrough, not when the inspector flags it at frame stage.
Slab Verification Before You Commit a Price
Quoting off the garage’s exterior footprint without checking the slab is how Altadena homeowners get change orders at foundation stage. We verify slab level and thickness before we price the job. That first visit is free, and it changes the number on paper, not after demolition starts.
Trusted Brands We Service in Altadena
For Altadena homeowners considering a prefab path, we are fluent with Abodu, Cover, and Dvele platforms and can run a factory-built garage conversion or ADU against your parcel’s setback and fire zone constraints. We also build conventional garage conversions using James Hardie fiber-cement siding, which satisfies the WUI exterior requirement without sacrificing the craftsman look common on Altadena’s older homes. For smaller budget projects, Tuff Shed-style structures can be converted where the county’s fire review permits. We match the build method to your lot and budget, then hand you the written price for that method, not a placeholder number.
Common Garage Conversion Contractor Problems We See in Altadena Homes
- Scoping the job as a cosmetic remodel and missing fire zone upgrades. A garage conversion in Altadena is not paint and laminate. The county’s Very High Fire Hazard Severity Zone review often requires fire-rated wall assemblies and ember-resistant vents, and a price that ignores those line items will not survive first plan check.
- Quoting off the exterior footprint without verifying the slab. Many Altadena garages sit on slabs poured without rebar or with low spots at the rear corners. We measure slab thickness and level before pricing, because a bathroom or kitchen wet wall on a bad slab is a foundation repair, not a plumbing allowance.
- Assuming a 30-day plan check. Altadena county review combined with hillside or WUI addenda routinely runs 8 to 14 weeks, sometimes longer. A contractor who promises a 6-week start without accounting for that calendar is guessing, and the guess becomes your delay.
- Misreading the parcel’s setback and access constraints. Some Altadena lots have tight side yards or rear access only through a narrow drive. That changes how we stage materials, where a mini-split condenser can sit, and whether the garage’s existing roofline works for the new ceiling height. These are parcel-level details, not generic square-foot math.
Pricing for Garage Conversion Contractor in Altadena, CA
Here are the honest ranges for Altadena’s market. A garage-to-bedroom with a bathroom runs $80,000 to $115,000. A full garage apartment conversion with a kitchen and separate entrance runs $120,000 to $180,000. A detached garage conversion with fire-rated siding, ember-resistant vents, and wet walls at both ends runs $130,000 to $190,000. Permit fees, Title 24 reports, and structural calculations add $8,000 to $20,000 depending on scope and parcel. The Garrison Standard means that number goes in writing before work starts. The price you approve is the price on the final invoice.
Call (361) 315-4177 to schedule a free site walk and written estimate for your Altadena garage conversion.
We Also Serve Cities Near Altadena
Our crews work throughout the San Gabriel foothills. We serve Pasadena, La Canada Flintridge, San Marino, and Sierra Madre, and we coordinate scheduling out of our Los Angeles office so Altadena homeowners deal with one point of contact from first visit to final inspection.
Serving Altadena, CA - Our Local Coverage Area
We’re based in the Altadena 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 Altadena
Yes, in most of Altadena it does. The county maps much of this city inside the Very High Fire Hazard Severity Zone, which triggers a fire-rated assembly review for walls near the property line plus ember-resistant venting at gable ends and eaves. What that means in practical terms: fire-rated drywall on the inside, James Hardie fiber-cement or approved equivalent on the outside, and specific vent products at the roofline. We identify which upgrades your parcel needs during the first site walk, so the written price includes them from the start. Call (361) 315-4177 and we’ll tell you exactly what applies to your garage.
Plan check alone typically runs 8 to 14 weeks with the county, and hillside or WUI addenda can push the full permit calendar to 4 to 5 months before we ever get a green tag. Construction itself runs 8 to 12 weeks for most garage conversions. That means a realistic schedule from submittal to final inspection is 4 to 7 months, not the 6 to 8 weeks some contractors advertise. Call (361) 315-4177 and we’ll give you a week-by-week calendar for your specific parcel.
Three things change the price, and we find all three before we quote: a slab that’s too thin or out of level for a wet wall, fire-rated upgrades the county requires that weren’t in the original scope, and unforeseen foundation work at the garage perimeter. That’s why we verify slab thickness, review the fire zone requirements, and check the foundation before the written price goes out. If something hidden surfaces later, it’s added as a written change order you approve before we proceed. Call (361) 315-4177 to get the site walk scheduled and the unknowns out of your price.
Sometimes, yes. The county’s fire hazard review applies the same ember-resistant and fire-rated standards to any structure being converted to habitable space, but a Tuff Shed-style garage or a prefab shell can work if the foundation, insulation, and siding meet the WUI requirements. We’ve converted Abodu, Cover, and Dvele units on Altadena parcels where setbacks allowed, and we can tell you early whether your prefab shell is worth converting or better replaced. Call (361) 315-4177 with the make and year of your garage and we’ll give you a straight answer.
A garage apartment is a full living unit with its own kitchen, bathroom, and separate entrance, which means two wet walls, a dedicated electrical panel, and fire-separation details at the cooking appliance. A simpler garage conversion might be a bedroom, office, or studio without a kitchen, which skips the second wet wall and costs less. In Altadena, the difference is usually $40,000 to $60,000 in construction cost, plus the added slab work for the kitchen drain. We can price both paths from the same site walk, so you decide with real numbers in front of you. Call (361) 315-4177 to schedule that walk and see both written prices.
Fielding ADU Builders converted a detached two-car garage off Santa Rosa Avenue into a 480 square foot garage apartment, framing a 2×6 wall against the existing slab and sheathing it with James Hardie fiber-cement siding to satisfy the WUI exterior requirement. Our tech caught a 4-inch slab drop at the rear corner before drywall, which would have cracked tile, and we self-leveled it before setting the bathroom pan and mini-split. Final inspection cleared on the first pass once we added ember-resistant vents at the gable ends. That’s the standard we bring to every garage conversion in this city.
Written by Reed Calloway, Owner at Fielding ADU Builders, serving Altadena with permitted garage conversions, ADUs, and room additions built to The Garrison Standard.
