A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in South Whittier, CA
Adding an ADU in South Whittier means working with unincorporated Los Angeles County rules, older single-family lots, and homes built mostly between the 1940s and 1970s that often need utility upgrades before new square footage goes up. The good news: most South Whittier properties sit on lots large enough for a detached unit, and the County’s ADU ordinance now allows units up to 1,200 square feet on most residential parcels. Call (903) 568-7222 to get a written price before any work starts.
Why South Whittier Homes Are Different
South Whittier is unincorporated LA County, which means permits go through the County’s Department of Regional Planning rather than a city hall. That single fact shapes every ADU and addition we build here. Lot sizes tend to run larger than in neighboring Whittier proper, and many homes along streets like Mulberry Drive and Telegraph Road sit on flat to gently sloped parcels that were graded decades ago. The soil is mostly clay-heavy, which matters for foundation design: clay expands and contracts with moisture, so we routinely recommend deeper footings than a coastal project would need.
Housing stock runs older, too. A 1960s ranch on La Mirada Boulevard may still have its original 100-amp electrical panel, which is not enough to support a new ADU with a kitchen and mini-split HVAC. We flag that early in the estimate so the written price reflects a 200-amp panel upgrade if needed. South Whittier also sits close enough to the 605 and 5 freeways that traffic noise can influence where an ADU’s bedroom window faces, another detail we plan for rather than discover later.
Our Main South Whittier Services
South Whittier homeowners call us most about three projects: building a new ADU from the ground up, expanding the main house with a home addition, or adding a single room like a primary suite or office. Each has its own South Whittier page with local pricing and process details.
ADU Builders in South Whittier
A detached ADU is the fastest path to rental income or a private space for family. In South Whittier, the typical project is a one-bedroom unit between 400 and 800 square feet, often built as a prefab panel system from ADU Builders in South Whittier like Dvele or Abodu, then finished on site. County setbacks apply, so we measure the lot from day one and design the unit to fit without variances. You get a written price that covers foundation, utilities, panel, and finishes before you commit.
Home Addition Contractor in South Whittier
Expanding the main house works well on South Whittier’s larger lots, where a ground-level addition can add a family room, a second bath, or a full primary suite without touching the roofline. We check the existing foundation for slab settling, which is common on the area’s clay soil, and tie new footings into the old work so the addition does not pull away over time. Full details are on the Home Addition Contractor in South Whittier page, including how we handle County plan check and inspections.
Room Addition Contractor in South Whittier
A single room addition is often the most budget-friendly way to add a home office, nursery, or fourth bedroom. South Whittier’s older homes frequently have a den or covered patio that can be converted without new foundation work, which keeps the price lower. If a new footing is needed, we design for the local soil from the start. The Room Addition Contractor in South Whittier page walks through what to expect, including line-item pricing examples.
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 South Whittier
We build with and service prefab ADU brands including Dvele, Boxabl, and Mighty Buildings, plus James Hardie cladding for site-built additions. Panels and finish materials are ordered to the project schedule so nothing sits in the South Whittier sun for weeks. See our brands for the full list of what we can spec and install.
Pricing for ADU Company in South Whittier, CA
| Service | Typical range in South Whittier |
|---|---|
| Detached ADU (400 – 800 sq ft) | $180,000 – $320,000 |
| Prefab panel ADU (Dvele, Boxabl) | $160,000 – $290,000 |
| Garage conversion ADU | $110,000 – $180,000 |
| JADU (interior conversion) | $85,000 – $140,000 |
| Home addition (ground-level, 400+ sq ft) | $140,000 – $260,000 |
| Primary suite addition | $120,000 – $210,000 |
| Room addition (single room, 200 – 350 sq ft) | $65,000 – $130,000 |
| Electrical panel upgrade to 200-amp | $3,200 – $5,800 |
| Foundation work (clay soil footings) | $8,000 – $22,000 |
| Permits and plan check (County of LA) | $4,500 – $11,000 |
What pushes a South Whittier price higher than the low end: a 200-amp panel upgrade, deeper footings for clay soil, or a detached unit that needs a new gas line run from the street. Every quote we give is a written price before work starts, so the number on the estimate is the number you pay.
Neighborhoods We Serve in South Whittier
We cover all of South Whittier and the surrounding unincorporated pockets. Most of our ADU and addition projects are within a 10 to 15 minute drive of each other, which keeps scheduling straightforward.
- Whittier Junction area near Telegraph and Mills
- Neighborhoods off Mulberry Drive
- Streets flanking La Mirada Boulevard
- Residential blocks north of Imperial Highway
- Pockets near Amelia Mayberry Park
Service Area – Cities Near South Whittier
Our crews often work in adjacent cities and neighborhoods, including Los Angeles, CA, Long Beach, CA, Anaheim, CA, and Riverside, CA. Scheduling for South Whittier is coordinated through the brand’s Los Angeles office, with local crews dispatched directly to your project.
Serving South Whittier, CA - Our Local Coverage Area
We’re based in the South 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 South Whittier
Most South Whittier ADU projects move from signed contract to permit submittal within 2 to 3 weeks. County of Los Angeles plan check for ADUs is running faster than it did a few years ago, and prefab panel systems shorten the construction window once permits clear. Call (903) 568-7222 and we will give you a start-date range in writing.
Most South Whittier neighborhoods are not governed by an HOA, so County rules apply without an extra layer of review. If your block does have an HOA, California law limits their ability to prohibit ADUs outright. We check HOA covenants during the estimate so there are no surprises.
Often, yes. Homes built before the 1980s in South Whittier commonly still run 100-amp panels, and an ADU with a kitchen, laundry, and mini-split needs at least 200 amps. We include that upgrade in your written price up front, not as a change order halfway through. Call (903) 568-7222 for a 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 South Whittier Customers Say
"Booked a consult online and met the project manager two days later. Weekly progress updates arrived by text with photos. ADU finished on schedule."
- Hannah W."Clean, quiet crew. They respected the neighbors, kept noise to working hours, and swept the driveway every evening."
- Hope C."Communication was the best part. I always knew what was happening that week without having to ask."
- Dolly N.
