A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Castaic, CA
Adding an ADU or home addition in Castaic means working with sloping lots, high summer heat, and a mix of housing stock built from the 1950s through the early 2000s. Benson ADU Builders helps Castaic homeowners plan, price, and build accessory dwelling units and additions with written pricing before any work starts. Whether you’re adding a detached prefab unit behind an existing home or extending a single-story rancher, we’re the ADU company Castaic homeowners call at (903) 568-7222.
Why Castaic Homes Are Different
Castaic sits in the Santa Clarita Valley’s northern stretch, where summer temperatures regularly climb past 100 degrees and lots often carry a noticeable grade. That heat changes how we spec insulation, window placement, and HVAC sizing for an ADU. A unit that works fine in a mild coastal climate will bake in Castaic if the roof assembly and glazing aren’t designed for it from day one.
The housing stock here runs from older single-story ranchers in the Hasley Canyon and Sloan Canyon areas to newer two-story homes in the communities near Castaic Lake and Hillcrest. Many of the older homes were built before ADU regulations existed, which means setbacks, utility connections, and fire-mitigation requirements can vary from street to street. We work those details into the written estimate, not as a surprise later.
Some Castaic neighborhoods have HOAs with their own design review rules, and the hillside areas can require additional grading or retaining work. That’s one reason we walk every lot before writing a price. The terrain, the access path for equipment, the distance to the nearest sewer or electrical panel – those are Castaic-specific realities that show up on the first site visit, not on a generic quote from a call center.
Our Main Castaic Services
Castaic homeowners most often ask us about two things: building a new ADU and adding living space to the home they already have. Each service has its own Castaic page below.
ADU Builders in Castaic
We build attached and detached ADUs in Castaic, from garage conversions to freestanding prefab units delivered and set on site. A detached ADU on a Castaic hillside lot needs proper foundation anchoring and a utility run that accounts for the slope. We spec those details before you sign anything. Get the full breakdown on ADU Builders in Castaic.
Home Addition Contractor in Castaic
A home addition in Castaic often means extending a living room, adding a primary suite, or building out a second story. Older Castaic homes frequently have panel and foundation conditions that need addressing before framing begins, and we catch those in the written estimate stage. See how Home Addition Contractor in Castaic works.
Room Addition Contractor in Castaic
A single room addition, like a home office or a fourth bedroom, is one of the most cost-effective ways to gain square footage in Castaic without moving. We handle the full scope: foundation, framing, roof tie-in, drywall, electrical, and finish work. Learn more on the Room Addition Contractor in Castaic 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 Castaic
We build with Cover, Dvele, and Boxabl prefab systems, and our Castaic crews keep commonly needed panel and finishing parts sourced from those manufacturers close at hand. When a panel or component needs replacement, turnaround is usually days, not weeks. Browse our brands for specifics.
Pricing for ADU Company in Castaic, CA
| Service | Typical range in Castaic |
|---|---|
| Detached ADU (site-built) | $180,000 – $380,000 |
| Detached ADU (prefab) | $120,000 – $280,000 |
| Garage conversion ADU | $90,000 – $180,000 |
| JADU (junior ADU) | $55,000 – $120,000 |
| Home addition (mid-size) | $95,000 – $220,000 |
| Room addition (single room) | $45,000 – $110,000 |
| Primary suite addition | $80,000 – $180,000 |
| Second-story addition | $140,000 – $320,000 |
Sloped lots in Castaic tend to push foundation and grading costs up, and homes in HOA communities can add design review fees. Every Benson ADU Builders project starts with a written price before any work starts, so the number on the table is the number you pay, not a starting point for change orders.
Neighborhoods We Serve in Castaic
We work across Castaic, from the hill communities near Castaic Lake to the valleys around Hasley Canyon, Sloan Canyon, and Hillcrest. Crews are typically on site within a few days of contract signing, depending on scope and permit intake.
- Hasley Canyon
- Sloan Canyon
- Hillcrest
- Castaic Lake areas
- Val Verde border communities
Service Area – Cities Near Castaic
Beyond Castaic, we serve homeowners across the Santa Clarita Valley, including Valencia, CA, Stevenson Ranch, CA, Santa Clarita, CA, and Newhall, CA. If you’re just outside Castaic in one of those communities, we’ll bring the same written pricing and 365-Day Done Right Promise to your project.
Serving Castaic, CA - Our Local Coverage Area
We’re based in the Castaic 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 Castaic
We schedule site visits across Castaic within a few business days of your call. The visit includes a lot walk, measurements, and a discussion about access, utilities, and any HOA or hillside considerations. Call (903) 568-7222 and we’ll get you on the schedule.
It depends on the neighborhood. Some Castaic communities have active HOAs that require design review before construction starts, and others do not. We check on that for you during the estimate phase so your written price accounts for the correct path from day one.
Only if you change the scope. Our written price covers the project as specified, including the Castaic-specific site conditions we identify during the walkthrough. If you add square footage or upgrade finishes after signing, we price that change in writing before proceeding. Call (903) 568-7222 for a free estimate on your Castaic project.
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 Castaic 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.
