A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in San Dimas, CA
Benson ADU Builders handles accessory dwelling units, home additions, and room additions in San Dimas, CA, with a written price before any work begins. San Dimas homes sit across sloping foothill lots and older ranch-era tracts, which means drainage, setbacks, and access to the rear yard shape nearly every project here. We build with prefab systems from Abodu, Cover, and Dvele, and every job carries the 365-Day Done Right Promise. Call (903) 568-7222 to schedule a free estimate.
Why San Dimas Homes Are Different
San Dimas runs from the 210 Freeway up into the foothills of the San Gabriel Mountains, and the housing stock shifts as you climb. Closer to Bonita Avenue and downtown, you find postwar single-story homes from the ’40s and ’50s with long, deep lots. Up near Via Verde and San Dimas Canyon Road, properties sit on steeper terrain, and some of those lots have drainage challenges that have to be resolved before an ADU foundation goes in. A backyard that looks flat from the kitchen window often has a 6 to 10 percent grade once we shoot elevations, which affects the masonry cost and sometimes the height of the stem wall.
The other thing that separates San Dimas from surrounding cities is the mix of horse-trail easements and hillside parcels on the northwestern edge. We pull city setback and fire-marshal requirements into the plan before breaking ground. These details matter because San Dimas requires setbacks and height limits to be verified against the specific zoning for your parcel, not just the general county rules. If you live near Puddingstone or east of San Dimas Avenue, access for a telehandler or concrete pump can be tight, so the site plan and the build sequence are planned around that from day one.
Our Main San Dimas Services
San Dimas homeowners call Benson ADU Builders for three types of work most often: detached ADUs, additions that expand the footprint of the main house, and room conversions. Each has its own San Dimas page with the details, pricing, and permits explained.
ADU Builders in San Dimas
A detached ADU in San Dimas is the fastest way to add a rent-ready unit or a private place for family without touching the main house. The local lots, especially the deep ones south of Arrow Highway, usually have room for a 500 to 800 square foot one-bedroom unit. We help you choose between a prefab panel system from Abodu or Cover and a site-built design, then handle the setback check, foundation, utilities, and finish work. ADU Builders in San Dimas covers the full process and what to budget.
Home Addition Contractor in San Dimas
A home addition in San Dimas typically means pushing out the back of a ranch-style house to gain a larger kitchen, a family room, or a primary suite. The old framing and foundation lines on those 1950s and 1960s homes need to be matched carefully, because slab thickness and roofline pitch vary from one end of a street to the next. We check the structural path before pricing so the written quote you receive is the price you pay. Home Addition Contractor in San Dimas explains the trade-offs of up versus out.
Room Addition Contractor in San Dimas
A room addition is the smaller, tight scope version: one bedroom, a home office with a closet, a playroom off the living area. San Dimas homeowners often convert a covered patio that is already under roof or bump a single wall out 10 to 14 feet. The value here is speed, since we are not reworking the entire floor plan. Room Addition Contractor in San Dimas shows what a single-room project costs and how long it takes from permit to paint.
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 San Dimas
We build with Abodu, Cover, Dvele, and Mighty Buildings prefab systems, and stock the common replacement parts and panels those systems use. That means warranty work and post-install fixes on most of the prefab ADUs we install in San Dimas get handled from the same local crew, usually in one trip. Our brands page shows what each option offers.
Pricing for ADU Company in San Dimas, CA
| Service | Typical range in San Dimas |
|---|---|
| Detached ADU (prefab, 400 – 600 sq ft) | $145,000 – $260,000 |
| Detached ADU (site-built, 500 – 800 sq ft) | $210,000 – $380,000 |
| Garage conversion ADU | $95,000 – $175,000 |
| Attached ADU / JADU | $120,000 – $210,000 |
| Home addition (200 – 400 sq ft) | $90,000 – $210,000 |
| Home addition (400 – 700 sq ft) | $160,000 – $340,000 |
| Room addition (single room, 150 – 250 sq ft) | $55,000 – $130,000 |
| Prefab panel material package only | $40,000 – $95,000 |
Hillside lots and parcels with a pronounced slope push foundation and drainage costs up in San Dimas, often by 10 to 20 percent versus a flat lot. Every Benson ADU Builders project includes a written price before work starts, so the number we quote is the number you approve, not a starting point.
Neighborhoods We Serve in San Dimas
We work across all of San Dimas, including the hillside streets, the older downtown grid, and the master-planned pockets along the 210 corridor. Response time for a free estimate is usually one to two business days, and we schedule site visits around the homeowner’s access, not a rotating sales schedule.
- Downtown San Dimas (near Bonita Avenue)
- Via Verde
- San Dimas Canyon Road area
- Puddingstone / East San Dimas Avenue
- Arrow Highway corridor
Service Area – Cities Near San Dimas
While this page covers San Dimas specifically, our crews also handle ADU and home addition work in the adjacent foothill cities. If you are just over the line in La Verne, CA, Glendora, CA, Covina, CA, or Azusa, CA, the same written-price process applies.
Serving San Dimas, CA - Our Local Coverage Area
We’re based in the San Dimas 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 San Dimas
We typically reach San Dimas homeowners within one to two business days for a free site visit. Call (903) 568-7222 and a live person answers, day or night, to put you on the schedule.
Some San Dimas neighborhoods have HOAs with design review requirements, but California state law limits an HOA’s ability to block an ADU. We check HOA rules early so the written quote covers any extra design or finish requirements before you commit.
No. The written price we give you is fixed before any work starts. If the city or HOA requires a specific change to the plan, we show you the line-item cost in writing before the change is approved, never after.
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 San Dimas 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.
