A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Whittier, CA
Whittier homes run older than most of Los Angeles County. A lot of the housing stock went up between 1920 and 1960, which means small lots, detached garages, and floor plans that were not built for a second unit. Fielding ADU Builders handles that reality every day. We’re the ADU and room-addition arm of Garrison Partners, working across Whittier on garage conversions, backyard units, and additions that fit the existing house instead of fighting it. If you’re weighing options, call (361) 315-4177 and we’ll answer your questions in plain terms.
Why Whittier Homes Are Different
Walk through the neighborhoods around Uptown, Michigan Park, or the hills above Whittier College and you’ll see the same thing: 75-year-old stucco homes on lots that have been carved up over generations. That age matters. Many Whittier garages date to the 1940s and 1950s, built as storage for one car and never meant to hold a living space. Converting one means addressing a slab that was poured without vapor barriers, electrical panels that are already maxed out, and rooflines that were framed before modern span tables existed.
The hill sections add another layer. Whittier sits against the Puente Hills, and the slope changes block to block. A level lot in the flats near Uptown has different drainage and setback questions than a lot climbing toward the Greenway Trail. Hillside ADUs almost always need deeper foundations and more attention to retaining walls, which changes both the price and the timeline. The soil ranges from decent to expansive clay, and we plan footings accordingly. Add Whittier’s own planning department requirements on top of that, and you’re not working off a template. You’re working off the lot you actually own.
Our Main Whittier Services
Whittier homeowners reach out to us for three jobs more than any others. Each one has its own page with specific pricing, process, and permit details.
Room Addition Contractor in Whittier
A room addition in Whittier usually means expanding a bedroom out into a side yard, adding a master suite, or pushing a living room into a covered patio. The houses are small by modern standards, so even 250 square feet changes how a family uses the home. Whittier’s older foundations often need selective retrofit work before the new framing ties in, and hillside lots may trigger additional grading review. We price the job in writing before any work starts, and the crew arrives background-checked and in uniform. Room Addition Contractor in Whittier has the full breakdown.
Garage Conversion Contractor in Whittier
Garage conversions are the fastest path to extra living space in Whittier because the structure already exists. You’re not paying for new slab work or exterior walls, but you are paying to bring a 70-year-old garage up to habitability standards: insulation, drywall, electrical, and often a new roof. Whittier’s detached garages sit tight to the lot line on many blocks, which can trigger setback reviews when you convert to living space. We handle that paperwork as part of the permit package. Garage Conversion Contractor in Whittier covers costs and timelines.
ADU Builders in Whittier
Backyard ADUs in Whittier range from compact one-bedroom units to larger two-bedroom builds, often on lots where the main house sits close to the rear property line. That tight layout means we plan access carefully before framing starts. We work with prefab platforms like Cover and Dvele when speed matters, and we build conventional units with James Hardie siding when the design calls for it. Reed Calloway runs the operation and stands behind the written one-year guarantee on every unit. ADU Builders in Whittier explains the build methods and trade-offs.
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 Whittier
We work with several prefab and modular systems, including Cover, Dvele, Mighty Buildings, and Boxabl. Parts and panels are ordered ahead of the build window so they’re on site when the crew needs them. Our brands page lists the full range.
Pricing for ADU Company in Whittier, CA
| Service | Typical range in Whittier |
|---|---|
| Garage conversion (attached) | $85,000 – $145,000 |
| Garage conversion (detached) | $95,000 – $165,000 |
| Backyard ADU (1-bedroom, prefab) | $140,000 – $220,000 |
| Backyard ADU (1-bedroom, conventional) | $160,000 – $250,000 |
| Backyard ADU (2-bedroom, prefab) | $200,000 – $300,000 |
| Backyard ADU (2-bedroom, conventional) | $230,000 – $350,000 |
| Kitchen addition (200 sq ft) | $75,000 – $130,000 |
| Primary suite addition (400 sq ft) | $140,000 – $220,000 |
| Second-story addition (600 sq ft) | $240,000 – $380,000 |
| Room addition (modest, 300 sq ft) | $95,000 – $165,000 |
Hillside lots in Whittier push prices toward the upper end because of added foundation work and retaining walls. Older panels and undersized gas lines also add cost when the existing infrastructure can’t support the new square footage. What doesn’t change: the price goes in writing before any work starts, and the number you approve is the number on the final invoice.
Neighborhoods We Serve in Whittier
Our crews work throughout Whittier, from the flat blocks near Uptown to the hill sections along the Greenway Trail. We schedule across the city in a single week rather than spreading a job over several.
- Uptown Whittier and the historic district
- Michigan Park
- The hills above Whittier College
- East Whittier near La Serna
- The neighborhoods along Whittier Boulevard toward the Greenway Trail
Service Area – Cities Near Whittier
We also serve the surrounding cities for homeowners planning an ADU, garage conversion, or room addition. Our Whittier crews cover Pico Rivera, CA, South El Monte, CA, Hacienda Heights, CA, and Montebello, CA. Dispatch and scheduling are coordinated from the brand’s Los Angeles office, with crews working locally in Whittier every week.
Serving Whittier, CA - Our Local Coverage Area
We’re based in the Whittier 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 Whittier
We schedule estimates in Whittier within the same week in most cases, and often sooner. Call (361) 315-4177 and a live person answers, day or night. You’ll get a written price before any work is scheduled.
Some Whittier neighborhoods have HOAs with their own design review on top of city permits. We handle the city paperwork and coordinate with the HOA when one exists, so you’re not chasing approvals on your own. The process starts with a free estimate.
Yes. Every ADU, garage conversion, and room addition we build in Whittier carries The Garrison Standard: a written one-year guarantee covering workmanship defects. If something fails inside that year, we return and correct it at no charge. Call (361) 315-4177 to schedule your free estimate.
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 Whittier Customers Say
"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."Clear price breakdown. Change orders were all in writing."
- Hal P."Solid job. Cabinet delivery was a week behind but they worked around it."
- Ben G.
