A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Westminster, CA
Benson ADU Builders is the ADU company Westminster homeowners call when they want a written price before work starts, not after. Adding an ADU or home addition here means working with a housing stock built mostly between the 1950s and 1970s, on flat lots with older electrical panels and sewer lines that often need attention before framing begins. We build with Abodu, Cover, and Dvele prefab systems alongside site-built additions, so you get options instead of a take-it-or-leave-it quote. Call (903) 568-7222 and you’ll get a live person, never a voicemail loop.
Why Westminster Homes Are Different
Westminster’s original tract homes went up fast in the postwar boom, which means most lots are between 5,000 and 7,200 square feet with predictable setbacks. That’s actually good news for ADU work: the flat terrain keeps grading costs low, and the standard lot shapes make prefab panel delivery simpler than in hilly parts of the county. What we do see often is outdated electrical service. Many Westminster homes still run 100-amp panels, and an ADU with a kitchen and laundry typically requires an upgrade to 200 amps. We flag that in the written price up front, not as a surprise change order.
The other Westminster-specific factor is the mix of older stucco exteriors and mid-century roof lines. Matching a room addition to an existing stucco finish takes a mason who knows how to blend texture so the seam disappears. Same with roofing: many homes here have low-slope comp shingle roofs that need careful tie-in work when we extend the footprint. If you live near the Westminster Mall area or up toward Bolsa Chica Road, expect extra attention to drainage, since those neighborhoods sit low and flat. We plan every Westminster project around the actual conditions of your lot, not a generic checklist.
Our Main Westminster Services
Westminster homeowners typically call us for one of two things: a detached or attached ADU in the backyard, or a home addition that expands the main living footprint. Each service has its own Westminster page with detailed pricing and process notes.
ADU Builders in Westminster
An ADU in Westminster usually means either a detached backyard unit or a garage conversion, and the city’s lot sizes determine which one fits. Most Westminster backyards can accommodate a 400 to 800 square foot detached unit without eating the whole yard, especially on the deeper lots south of the 22. We handle the full scope: plans, permits, foundation, utilities, and finish work. Prefab options from Abodu and Cover shorten on-site time significantly compared to stick-built. Read the full breakdown on our ADU Builders in Westminster page, including price ranges and what the 365-Day Done Right Promise covers.
Home Addition Contractor in Westminster
A home addition in Westminster typically extends the back or side of the house to add a family room, primary suite, or second story. These projects run into the same older-home realities we see across the city: panel upgrades, stucco matching, and sometimes foundation reinforcement on 60-year-old slabs. We pull permits, schedule inspections, and keep you updated with photos and a live timeline. The Relay Visibility Guarantee means every Westminster home addition gets a written price before any work begins. See full details and local pricing on the Home Addition Contractor in Westminster page.
Room Addition Contractor in Westminster
A room addition is the smaller cousin of a full home addition: one bedroom, a home office, or a bumped-out kitchen. Westminster homeowners often use these projects to add a downstairs bedroom when an aging parent moves in, or to carve out a dedicated workspace. Because these jobs are smaller, the written price matters even more: you should know the exact cost before drywall goes up. We use the same process on a 200 square foot room addition as on a full second story. Visit the Room Addition Contractor in Westminster page for pricing and what to expect from the build timeline.
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 Westminster
We’re authorized to build with Abodu, Cover, and Dvele prefab systems, and we install our brands across Westminster. Most prefab panels are staged at our regional yard and delivered to your lot on a schedule that matches the permit approval, so materials don’t sit exposed to weather. James Hardie cladding is our standard exterior option for Westminster homes, and it holds up well against the coastal humidity that rolls in most summer evenings.
Pricing for ADU Company in Westminster, CA
| Service | Typical range in Westminster |
|---|---|
| Detached ADU (prefab, 400 – 600 sq ft) | $180,000 – $260,000 |
| Detached ADU (site-built, 400 – 600 sq ft) | $220,000 – $340,000 |
| Garage conversion ADU | $130,000 – $190,000 |
| Attached JADU conversion | $95,000 – $150,000 |
| Home addition (single story, 300 – 400 sq ft) | $130,000 – $220,000 |
| Home addition (primary suite) | $150,000 – $260,000 |
| Second-story addition | $260,000 – $400,000 |
| Room addition (bedroom or office) | $60,000 – $120,000 |
| Kitchen bump-out | $70,000 – $150,000 |
| Electrical panel upgrade to 200 amps | $3,500 – $6,000 |
Prices climb in Westminster when a project needs a sewer line replacement, panel relocation, or stucco remediation around the tie-in point. And here’s the important part: every one of these numbers is put in writing before you sign anything. No allowances, no open-ended line items, no “we’ll see how it goes.”
Neighborhoods We Serve in Westminster
Our crews work across the full Westminster grid, from the neighborhoods along Bolsa Avenue to the residential blocks near the Westminster Mall and down to the edges of Midway City. Most schedules route us inside Westminster within about 45 minutes of a neighbor’s job, so inspection visits and follow-up calls don’t leave you waiting around.
- Bolsa Chica Road corridor
- Westminster Mall area
- Little Saigon adjacent blocks
- Goldenwest Street neighborhoods
- Northwest Westminster near the 405
Service Area – Cities Near Westminster
Benson ADU Builders runs projects in Westminster and the neighboring cities that share the same lot patterns and permit realities. If you’re just over the border, we’re likely already working in your area. We also serve Midway City, CA, Huntington Beach, CA, Stanton, CA, and Fountain Valley, CA.
Serving Westminster, CA - Our Local Coverage Area
We’re based in the Westminster 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 Westminster
Once permits are approved, we typically mobilize within two to three weeks. The bigger variable is city plan check, which moves on Westminster’s timeline, not ours. What we control: every crew member shows up background-checked and in uniform, and your written price is locked before demolition begins. Call (903) 568-7222 to get your project in the queue.
If your Westminster property falls under an HOA, check your CC&Rs before we file plans. California state law limits HOA authority over ADUs, but some Westminster communities still have architectural review requirements. We flag this early and adjust the schedule around it so you’re never caught off guard.
We cover Westminster and the adjacent cities of Midway City, Huntington Beach, Stanton, and Fountain Valley. Scheduling and dispatch are coordinated from the brand’s Los Angeles office, while crews serve Westminster locally. Call (903) 568-7222 for a free estimate and we’ll confirm coverage on the first call.
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 Westminster 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.
