A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Santa Monica, CA
Getting an ADU built in Santa Monica, CA means working within one of the strictest coastal building environments in Los Angeles County. The city runs its own building department, enforces its own energy and coastal codes, and reviews every project against zoning rules that change more often than most homeowners expect. We handle the full build, from the first site visit through final inspection, and we put the price in writing before any work starts. If you’re weighing a backyard unit, a garage conversion, or a room addition, call us at (361) 315-4177 and we’ll walk you through what your property can support.
Why Santa Monica Homes Are Different
Most homes in Santa Monica were built between the 1920s and the 1960s. That means pier-and-beam foundations, knob-and-tube wiring that sometimes hasn’t been touched since the Eisenhower years, and lot lines that don’t always match what the county records say. Any addition or ADU here starts with a close look at what’s already under the house, because the foundation and the electrical panel drive the cost more than the size of the new room does.
The climate works in your favor on the coast, but it still shapes the job. Salt air eats at exposed fasteners and flashing faster than it does ten miles inland, so we spec corrosion-resistant hardware on exterior work by default. The setback rules in Santa Monica are also tighter than what most state ADU law allows, because the city has kept local restrictions on height and rear-yard coverage. When we talk to homeowners in Sunset Park or north of Montana Avenue, the conversation usually starts with what the parcel can actually hold, not what the brochure says.
Terrain matters less here than in the hills above the city, but the flat lots between Wilshire Boulevard and Pico Boulevard still have quirks. Older neighborhood sewer lines run shallow in some blocks, which affects where a detached ADU can sit without triggering a costly line relocation. We check that before we draw anything.
Our Main Santa Monica Services
Most Santa Monica homeowners come to us for one of two things: adding square footage to the main house, or converting existing space into a legal dwelling unit. The three services below have their own dedicated pages with local pricing and specifics.
Room Addition Contractor in Santa Monica
A room addition in Santa Monica usually means extending the back of the house into the yard, sometimes with a second story if the lot is narrow. The city wants structural plans stamped by a California engineer, and older homes often need a lateral retrofit as part of the permit package. We have done enough of these in Santa Monica to schedule the engineering review early so it doesn’t stall the job. The full scope, from foundation to roof, is covered in detail on our dedicated page.
Room Addition Contractor in Santa Monica
Garage Conversion Contractor in Santa Monica
Converting a detached garage into an ADU is often the fastest permit path in Santa Monica, because the structure already exists and the city has a streamlined review for these projects. The work usually involves pouring a new slab or leveling the old one, reframing the garage door opening, running new electrical and plumbing, and insulating to meet Title 24 energy rules. The condition of the existing garage changes the price more than anything else, and we walk you through that on the page below.
Garage Conversion Contractor in Santa Monica
ADU Builders in Santa Monica
Detached ADUs are the largest single investment most Santa Monica homeowners make on their property, and the city reviews them carefully. Setback rules, height limits, and lot coverage all come into play, and some parcels need a variance to build at all. We work with both conventional site-built construction and prefab platforms like Abodu and Cover, which can shorten the on-site timeline significantly. See the full breakdown on our Santa Monica ADU 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 Santa Monica
We build with the systems Santa Monica homeowners already research. Our crews work with Abodu, Cover, Dvele, and Mighty Buildings, and we stock the common parts for each locally so a missing bracket doesn’t stall the framing schedule. Full details are on our brands page.
Pricing for ADU Company in Santa Monica, CA
| Service | Typical range in Santa Monica |
|---|---|
| Detached ADU (site-built, 400 – 800 sq ft) | $180,000 – $360,000 |
| Detached ADU (prefab, 400 – 600 sq ft) | $125,000 – $275,000 |
| Garage conversion to ADU (legalization included) | $95,000 – $185,000 |
| Attached ADU (interior conversion within existing footprint) | $80,000 – $170,000 |
| Room addition (200 – 400 sq ft) | $60,000 – $140,000 |
| Room addition (400 – 800 sq ft) | $110,000 – $235,000 |
| Second-story addition | $190,000 – $380,000 |
| Foundation upgrade (pier-and-beam repair or replacement) | $8,000 – $30,000 |
| Electrical panel upgrade (100A to 200A) | $3,500 – $8,000 |
| Site prep and utility trenching | $5,000 – $18,000 |
Prices in Santa Monica run higher than inland areas because of city-level permit fees, coastal structural requirements, and the age of the housing stock. Anything that triggers a variance or a sewer-line relocation adds to the total. Whatever the number is, we put it in writing before the first nail goes in, and that number doesn’t move at the end of the job.
Neighborhoods We Serve in Santa Monica
We cover every neighborhood in the city, from the Ocean Park flats to the hills above San Vicente Boulevard. Our crews are based in the Los Angeles metro area and schedule Santa Monica jobs throughout the week, so a typical estimate visit happens within a few days of your call, not weeks.
- Sunset Park
- Ocean Park
- Mid-City / Pico District
- North of Montana Avenue
- Wilshire/Montana
Service Area – Cities Near Santa Monica
In addition to Santa Monica, we build ADUs and additions in Venice, CA, Pacific Palisades, CA, Marina del Rey, CA, and Culver City, CA. Each city has its own building department and review process, but our pricing model stays the same: written quotes, permitted work, and a one-year written guarantee.
Serving Santa Monica, CA - Our Local Coverage Area
We’re based in the Santa Monica 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 Santa Monica
Once the plans are approved and the permit is issued, we typically break ground within two to four weeks, depending on crew scheduling and material lead times. The permit review itself is the variable, and Santa Monica’s building department generally takes three to six months for a standard ADU submittal. Call (361) 315-4177 and we’ll give you a realistic timeline for your specific property.
Yes, every ADU and garage conversion in Santa Monica requires a building permit, and most require a full plan check with structural and energy compliance review. The city does not recognize unpermitted conversions, which can complicate a future sale. We handle the permit package for you, and if the city asks for revisions, we answer them without charging you extra for the paperwork.
Properties inside the coastal zone may need an additional layer of review beyond standard city permits, and Santa Monica’s coastal regulations can be stricter than the state’s. We coordinate that review when it applies to your parcel, and our written price accounts for it up front so it doesn’t arrive as a surprise change order. For a lot-specific answer, call us at (361) 315-4177.
If you want to know what your Santa Monica property can support and what it will cost, call (361) 315-4177 for a free estimate. Reed Calloway and the Fielding ADU Builders team will walk you through the options, put the price in writing, and build it to The Garrison Standard.
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 Santa Monica 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.
