A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Altadena, CA
Fielding ADU Builders handles accessory dwelling units, garage conversions, and room additions in Altadena, CA. Homes here run older than most of Los Angeles County, which means we spend more time on foundation checks and electrical service upgrades before the first wall goes up. The terrain changes block to block, from flat lots near Lincoln Avenue to hillside parcels above Altadena Drive, and that affects setbacks, drainage, and how we stage materials. If you’re comparing ADU contractors, call (361) 315-4177 and we’ll put a written price in front of you.
Why Altadena Homes Are Different
Altadena’s housing stock leans heavily toward mid-century ranchers and a handful of pre-war bungalows, and most of them were built before current seismic and energy codes existed. That means an ADU project rarely starts with the ADU itself. We’re usually upgrading the main panel from 100 amps to 200, adding shear wall to an existing garage, or correcting drainage so a new structure doesn’t send runoff into a neighbor’s yard. Homes in the PresidentStreets neighborhood and along Marengo Avenue tend to sit on deeper lots, which helps with rear-yard ADUs, but front setbacks get tighter the closer you get to Lake Avenue.
Altadena sits against the San Gabriel Mountains, and that geography does two practical things. First, hillside lots often trigger additional grading review through Los Angeles County. Second, wildfire-adjacent zones bring stricter defensible-space and exterior-material requirements, including ignition-resistant siding options. None of this should scare a homeowner off. It does mean your contractor needs to know which questions to ask before drawing plans, and which permit counter handles your parcel. We do.
Our Main Altadena Services
Most Altadena homeowners call us about one of three projects. Each has its own page with pricing and specifics linked below.
Room Addition Contractor in Altadena
A room addition in Altadena usually means extending a ranch-style home outward or converting an enclosed patio into conditioned square footage. Older homes here frequently have post-and-beam framing, which is straightforward to tie into but shows settlement differently than newer stick framing. We check for that before we quote. The county requires full plans and inspections, and we handle both. See the full breakdown on our Room Addition Contractor in Altadena page.
Garage Conversion Contractor in Altadena
Garage conversions are the fastest path to rentable or in-law space in Altadena, and the county’s ADU rules make most detached garages eligible. What trips people up is the condition of the slab and the lack of insulation in older garage walls. We address both during the quote, not after. If your garage sits off an alley or behind a narrow driveway, that changes material access and cost. Details are on our Garage Conversion Contractor in Altadena page.
ADU Builders in Altadena
As an ADU builder, we run both conventional construction and prefab lines from Abodu, Cover, and Dvele where the lot supports them. Altadena’s varied topography means some parcels work better for a panelized unit than a stick-built one, and the county’s setback rules for ADUs are specific about how close a detached unit can sit to a property line. We walk the lot first, then recommend the build method. Pricing and build options are on our ADU Builders in Altadena page.
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.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Altadena
We regularly install and finish prefab ADUs from Abodu, Cover, and Dvele across Altadena. Each brand has a different foundation and utility-connection requirement, and we keep the common material callouts for those units on hand locally. Turnaround on prefab finishes is typically faster than a full stick build. More on that on our brands page.
Pricing for ADU Company in Altadena, CA
| Service | Typical range in Altadena |
|---|---|
| Detached one-bedroom ADU (site-built) | $180,000 – $260,000 |
| Detached one-bedroom ADU (prefab, installed) | $150,000 – $220,000 |
| Garage conversion to studio ADU | $95,000 – $140,000 |
| Garage conversion to one-bedroom ADU | $120,000 – $170,000 |
| Junior ADU (attached, under 500 sq ft) | $85,000 – $130,000 |
| Primary bedroom suite addition | $130,000 – $190,000 |
| Family room addition (300 – 400 sq ft) | $110,000 – $170,000 |
| Full kitchen addition | $120,000 – $185,000 |
| Second-story addition (bedroom and bath) | $220,000 – $320,000 |
| Seismic retrofit on existing garage before conversion | $8,000 – $18,000 |
| Electrical service upgrade to 200 amps | $3,500 – $6,500 |
| Site prep and grading on sloped Altadena lots | $10,000 – $30,000 |
Two things push price up in Altadena more than anywhere else: slope work and electrical panels on older homes. The number you approve on day one is the number on the final invoice because every Fielding ADU Builders project gets a written price before any work starts.
Neighborhoods We Serve in Altadena
We work across all of Altadena, CA. Each neighborhood has its own lot patterns and setback quirks, but the county’s permit path is the same everywhere in the unincorporated area.
- PresidentStreets
- The Meadows
- Altadena Crest
- Lake Avenue corridor
- La Vina
We typically schedule estimate visits within a few business days anywhere in the Altadena service area.
Service Area – Cities Near Altadena
Fielding ADU Builders serves Altadena and the surrounding foothill and valley communities. We also handle ADU, garage conversion, and room addition work in Pasadena, CA, La Canada Flintridge, CA, San Marino, CA, and Sierra Madre, CA. Dispatch and scheduling are coordinated from our Los Angeles office; crews serve Altadena locally.
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 ADU Company in Altadena
After your written estimate is approved, we typically begin the permit package within two weeks. Los Angeles County review times vary by project type; prefab ADUs from Abodu or Cover often move faster because their plans are pre-reviewed. Call (361) 315-4177 for a current timeline on your specific lot.
Some Altadena neighborhoods, including La Vina, have HOAs with architectural review requirements on top of county permitting. State ADU law limits what an HOA can prohibit, but you still need their sign-off before we pull permits. We coordinate that paperwork as part of the project.
Yes. Hillside parcels often need grading review, retaining wall coordination, and sometimes a soils report before an ADU is approved. We walk the lot with that in mind from the first visit. Call (361) 315-4177 to schedule a free estimate and we’ll tell you exactly what your slope requires.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Altadena Customers Say
"Foundation and slab poured on schedule. Crew kept the yard orderly."
- Marian J."Garage conversion with a new bath and kitchenette. Permit was handled by them. Inspection passed first time."
- Sheila B."Honest feedback on what the lot could fit. Told me up front what would fit on the lot and what the setbacks would allow."
- Rita C.
