A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Fillmore, CA
We’re Sutton ADU Ventura, and we build accessory dwelling units, home additions, and room additions in Fillmore. Adding square footage here isn’t a copy-paste job from a nearby city. Fillmore’s pre-1940 Craftsman and Spanish Colonial homes sit on narrow, deep lots, many still on septic or aging clay sewer laterals, and the inland valley heat punishes anything undersized. If you’re pricing an ADU or addition in Fillmore, the numbers below are real. Call (350) 238-1748 for a written estimate before any work starts.
Why Fillmore Homes Are Different
Fillmore is one of the last Ventura County towns where a meaningful share of housing predates World War II. We regularly work on single-story, wood-framed homes from the 1920s through 1940s, plus the post-war ranch band that filled in later. Those older homes have two things that change a build: original clay sewer laterals and shallow, pre-1978 foundations. Adding an ADU means adding bathrooms and a kitchen. That means added load on a lateral that may predate plastic pipe. We’ve seen pre-1940 laterals here that collapse during excavation, and a lateral inspection is often the single most valuable pre-build check a Fillmore homeowner can do.
Climate matters too. Fillmore’s summers bring regular 100°F days, and the valley traps heat. An ADU or addition designed without serious attention to cooling load becomes a hotbox by July. We spec insulation, glazing, and HVAC sizing for inland valley conditions, not coastal assumptions. Winter is the flip side: heavy rain events mean drainage and grading near the Santa Clara River low areas must be done right the first time. A poorly graded ADU pad in a wet Fillmore winter becomes a standing-water problem by February.
Fillmore’s newly adopted ADU ordinance permits detached units on lots smaller than surrounding cities allow. That’s a real opportunity: the 5,000-square-foot lot that doesn’t qualify in Moorpark or Santa Paula may qualify here. It also means setbacks (the required gap between your new structure and the property line) and lot-coverage rules are the first thing we check on a site visit, because they determine what you can actually build before you spend a dollar on plans.
Our Main Fillmore Services
Most Fillmore homeowners call us about one of three things: an addition off the existing house, a detached ADU in the back, or a room addition that turns underused square footage into livable space. Each has its own Fillmore page with pricing and specifics.
Home Addition Contractor in Fillmore
A home addition in Fillmore usually means tying new foundation and framing into a 1920s-to-1940s home or a mid-century ranch. The older the house, the more often we find the original foundation needs shoring before new walls go up. Pre-1978 footings on Fillmore’s older stock are often shallower than current code, and matching rooflines on Craftsman and Spanish Revival homes takes actual carpentry skill, not a kit. Fillmore’s hot summers also mean we pay close attention to how the new envelope meets the old one, because that seam is where heat and air leaks happen. See Home Addition Contractor in Fillmore for full pricing and what a typical addition involves here.
ADU Builders in Fillmore
Detached ADUs are the fastest-growing request we get in Fillmore, and the new ordinance is a big reason why. Smaller lots qualify here than in neighboring cities, so a backyard unit that wouldn’t pencil out elsewhere often does in Fillmore. The catch is the older lots: narrow rear access limits how equipment gets to the build site, and original clay laterals frequently need replacement before an ADU can connect. We’ve done enough Fillmore ADUs to know the lateral inspection belongs in the budget from day one, not as a surprise line item. See ADU Builders in Fillmore for real price ranges and a breakdown of the process.
Room Addition Contractor in Fillmore
A room addition in Fillmore is often the most cost-efficient way to add square footage without touching the yard, especially on lots too small for a detached unit. We build single-room additions onto existing Fillmore homes, including the ranch-style stock where a straightforward gable addition can come together quickly. The same foundation realities apply: older Fillmore homes need footing checks before we frame, and the clay-lateral question still matters for any addition that adds plumbing. A bedroom addition that doesn’t add a bathroom is simpler and cheaper. See Room Addition Contractor in Fillmore for what a room addition costs in Fillmore and how long it typically takes.
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 Fillmore
We have hands-on experience with Cover, Dvele, and Mighty Buildings ADU product lines, and we regularly spec James Hardie cladding systems on Fillmore additions where the original siding needs to match or outlast the valley heat. We also handle Tuff Shed conversions for homeowners who want a faster, lower-cost permitted unit. See our brands for the full list and what we recommend for specific Fillmore lots.
Pricing for ADU Company in Fillmore, CA
| Service | Typical range in Fillmore |
|---|---|
| Detached ADU, 400-600 sq ft | $180,000 – $320,000 before site work |
| Detached ADU, 600-800 sq ft | $280,000 – $420,000 before site work |
| Garage conversion ADU | $120,000 – $190,000 |
| Home addition (ground-up), 300-500 sq ft | $120,000 – $225,000 |
| Room addition (single room, no plumbing) | $45,000 – $80,000 |
| Room addition with bathroom | $70,000 – $120,000 |
| Sewer lateral inspection and replacement | $3,500 – $9,000 when required |
| Foundation shoring and repair on pre-1978 homes | $8,000 – $25,000 when required |
| Site drainage and grading | $4,000 – $14,000 depending on lot slope |
What pushes a Fillmore price toward the top of a range: a pre-1940 home needing lateral replacement, foundation work on an old footing, steep rear access that limits equipment, and drainage work on low-lying lots near the Santa Clara River. Every estimate we give is a written line-item price delivered before any work begins, and it doesn’t change unless you change the scope in writing.
Neighborhoods We Serve in Fillmore
We build and add on throughout Fillmore, from the older grid of side streets around downtown to the post-war ranch neighborhoods and the eastside pockets that still rely on septic. Response and scheduling are coordinated from our Los Angeles office, but crews dispatch locally into Fillmore and surrounding cities within one business day for site visits.
- Downtown Fillmore and the surrounding pre-1940 blocks
- East Fillmore, including septic-served eastside neighborhoods
- The ranch-home band north of Telegraph Road
- Heritage Valley residential streets near Highway 126
- River-adjacent low-lying lots near the Santa Clara River
Service Area – Cities Near Fillmore
We serve Fillmore and the surrounding Ventura County cities. If you’re in Moorpark, CA, Santa Paula, CA, Somis, CA, or Simi Valley, CA, the same written-price and Threshold Verified crew standards apply. Each city has its own lot realities: Santa Paula shares Fillmore’s older housing stock, while Moorpark and Simi Valley trend newer. Call (350) 238-1748 to confirm we cover your address and schedule a site visit.
Serving Fillmore, CA - Our Local Coverage Area
We’re based in the Fillmore 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 Fillmore
We schedule initial site visits in Fillmore within one business day on most requests. Scheduling is handled from our Los Angeles office, but a live person answers every call, 24/7, and queues the visit to a local crew. Call (350) 238-1748 and you’ll get a person, not a voicemail tree.
Yes. Every ADU, home addition, and room addition in Fillmore requires city permits, and the city’s newer ADU ordinance sets specific rules for lot size, setbacks, and height. We handle the permit submittal and the inspections; we don’t ask you to pull your own permits. Estimates are free and the permit cost is a written line item.
Yes. Several eastside Fillmore neighborhoods still use septic, and an ADU or addition that adds bedrooms or bathrooms may require septic system review or upgrade, not just connection to an existing lateral. We flag this early in the site visit so it’s in the written estimate from the start. Call (350) 238-1748 for an exact quote on your lot.
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 Fillmore Customers Say
"They handled the drawings and the permit paperwork for us. All I had to do was pick the finishes."
- Rosa M."Straight answers on what we could and couldn't do on our lot."
- Edwin H."Insulated the walls and ceiling properly. It stays comfortable even in July."
- Tamika W.
