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
We’re Benson ADU Builders, and we handle ADU construction, home additions, and room additions across Santa Monica, CA. Santa Monica’s housing stock runs older than most of the Westside, with a lot of 1920s and 1950s bungalows on tight lots where setbacks and parking rules shape every project from day one. Coastal moisture also plays a role in material choices and drainage planning. If you’re adding a backyard unit, expanding a kitchen, or converting a garage, call (903) 568-7222 and we’ll put the numbers in front of you before any commitment.
Why Santa Monica Homes Are Different
Santa Monica’s lots are famously compact. A standard 50-foot-wide parcel in Sunset Park leaves little room for error once you account for side and rear setbacks, which is why we measure twice before recommending a prefab panel system or a site-built addition. Many homes north of Wilshire date to the 1920s and 1930s, meaning foundation work and electrical upgrades often become part of the scope once walls open up. The marine layer is another factor: morning fog and salt air push us toward James Hardie cladding and corrosion-resistant fasteners, especially within a mile of the beach. In neighborhoods like Ocean Park and Mid-City, we also see strict planning review for anything visible from the street. None of this is a surprise when you work here regularly. It’s just the reality of building in Santa Monica, and it’s why our written pricing includes what other contractors bill as “unexpected” later.
Our Main Santa Monica Services
Santa Monica homeowners most often come to us for two things: building new ADUs and expanding the footprint of older homes. Here’s what each looks like locally.
ADU Builders in Santa Monica
Most Santa Monica ADUs are detached backyard units or garage conversions, with a growing number of JADUs carved from existing floor plans. The city’s zoning encourages accessory units, but every project still has to clear parking, height, and setback requirements that vary by block. We build with Abodu, Dvele, and Cover prefab systems when the site allows, which gets Santa Monica homeowners a factory-built frame and a much shorter on-site build window than traditional stick framing. If you’re weighing prefab against site-built, ADU Builders in Santa Monica covers pricing, timelines, and local permit realities in detail.
Home Addition Contractor in Santa Monica
Adding square footage to a Santa Monica home usually means going up rather than out, since side yards on most lots are only three to five feet wide. Second-story additions on 1920s bungalows require seismic evaluation and often a full foundation upgrade, which we scope and price before the first permit is pulled. Get the full breakdown on Home Addition Contractor in Santa Monica, including what to expect for engineering, plan check, and build time in this city.
Room Addition Contractor in Santa Monica
A room addition in Santa Monica is often the most efficient way to add a home office or a ground-floor bedroom without changing the roofline of the main house. We do a lot of bump-outs on the rear of homes in Pico District and Sunset Park, where the back yard has room to absorb the new footprint. One local condition that matters: many older Santa Monica homes have partial or failing foundations, so we always check before framing. The Room Addition Contractor in Santa Monica page explains what’s included and how long a typical project takes to permit and build.
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 are factory-authorized to build with Abodu and Cover prefab ADU systems, plus we install Dvele and Mighty Buildings panels on larger custom projects. Parts and materials come through our Los Angeles supply chain, so there’s no coastal delivery delay. Full catalog details are on our brands page.
Pricing for ADU Company in Santa Monica, CA
Here is what Santa Monica homeowners can expect based on the last year of local bids. Every figure below is a working range, not a bait quote. Your final written price depends on site access, foundation condition, and city requirements.
| Service | Typical range in Santa Monica |
|---|---|
| Detached prefab ADU (studio, Abodu or Cover) | $180,000 – $250,000 |
| Detached site-built ADU (1 bedroom) | $220,000 – $320,000 |
| Garage conversion to ADU (existing structure) | $130,000 – $190,000 |
| JADU (junior ADU from existing interior) | $90,000 – $140,000 |
| Home addition (ground-floor bump-out, 200-300 sq ft) | $140,000 – $220,000 |
| Second-story addition (400-600 sq ft) | $280,000 – $420,000 |
| Room addition (single room, 120-200 sq ft) | $80,000 – $140,000 |
| Foundation retrofit (seismic, during addition) | $25,000 – $60,000 |
| Electrical panel upgrade (required on most ADUs) | $4,000 – $8,000 |
| Permit and plan check costs (city fees) | $5,000 – $15,000 |
The two things that push Santa Monica prices higher than average are foundation condition and street access. Older homes near Ocean Park or Sunset Park often need seismic upgrades before framing starts, and narrow alleys make crane support and material delivery more expensive. Every Benson ADU Builders estimate includes a written price before work starts, with no change orders unless you change the scope.
Neighborhoods We Serve in Santa Monica
Our crews work throughout Santa Monica on a regular rotation. We know which blocks trigger extra plan review and which have enough rear yard depth for a standard prefab panel drop. Typical neighborhoods we serve include:
- Sunset Park
- Ocean Park
- Mid-City
- Pico District
- North of Montana
Response time across Santa Monica is usually within one business day for estimates, and every site visit is scheduled with a confirmed arrival window.
Service Area – Cities Near Santa Monica
While this page covers Santa Monica, our crews also work across the neighboring Westside and South Bay areas. If your project is one or two exits down the 10, we can help: Venice, CA, Pacific Palisades, CA, Marina del Rey, CA, and Culver City, CA.
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
Yes. A live person answers our phone 24/7, including weekends and holidays. You won’t reach a voicemail tree. Call (903) 568-7222 any time and you’ll speak with someone who can schedule your free estimate.
Most single-family homes in Santa Monica are not in HOAs, but a few condo and planned communities do exist. If you’re in an HOA, we’ll review your CC&Rs before the city permit is submitted and flag any restrictions. That review is included in our free estimate.
Most Santa Monica homeowners schedule us within three to five business days of calling. If you have a specific site-access window or need a weekend visit, telling us when you call helps us lock the slot. Estimates are free, and the written price comes before any work starts.
Call Benson ADU Builders at (903) 568-7222 for a free, written estimate on your Santa Monica ADU, home addition, or room addition. Troy Eastman and the team will put the plan and the price in writing before you commit to anything.
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
"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.
