A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Campbell, CA
Fielding ADU Builders handles ADU construction, garage conversions, and room additions throughout Campbell, CA. The city’s 1940s-1960s ranch homes on small lots mean most Campbell properties need a builder who understands tight setbacks, older foundations, and the design review process near downtown. Campbell’s mild climate keeps construction moving year-round, but the permitting path here is different from what you’ll find in more permissive neighboring cities. Call (669) 201-3984 for a written estimate.
Why Campbell Homes Are Different
Campbell is largely built out. The housing stock runs to single-story ranch and bungalow homes from the 1940s through the 1960s, most on lots between 5,000 and 7,000 square feet. That means the ADU you saw in a new development with a wide side yard won’t fit the same way here. We work with the lot as it exists: attached garages and carports become conversion candidates, and backyard setbacks drive placement decisions.
Soil conditions in Campbell are generally stable, which allows slab-on-grade ADU foundations in many cases. But homes of this era often sit on foundations that need evaluation before an addition ties in. A 1950s perimeter foundation may need retrofit work to meet current code, and the Campbell building department reviews that carefully.
The Pruneyard area and the downtown core around Campbell Avenue carry zoning overlays that change how projects move. Within roughly a half-mile of Campbell Avenue, expect additional design review and neighbor notification. That adds time and documentation, and it rewards builders who prepare plans that anticipate staff comments rather than reacting to them one round at a time.
Our Main Campbell Services
Campbell homeowners most often call us about three things: converting an existing garage or carport, adding a ground-floor room that fits the existing roofline, or building a detached ADU in the rear yard. Each service has its own Campbell page with pricing and details, linked below.
Room Addition Contractor in Campbell
Room additions in Campbell typically bump out the rear or side wall of a ranch home, and the challenge is matching a 1960s roofline and floor height while bringing the new section to current energy code. We handle the structural tie-in, foundation work, and the permit drawings the city requires. You can read the full scope and pricing on the Room Addition Contractor in Campbell page.
Garage Conversion Contractor in Campbell
Campbell’s attached garages and carports from the 1950s and 1960s are among the most common conversion projects we price. The garage slab, wall framing, and roofline are usually workable, but the electrical panel and the existing driveway layout often need rework to meet current code. We walk you through the Campbell-specific requirements on the Garage Conversion Contractor in Campbell page.
ADU Builders in Campbell
Detached ADUs in Campbell are usually backyard structures between 400 and 800 square feet, and the city’s design review process means plans must address massing, privacy, and how the unit reads from the street and the neighbor’s yard. We build conventional structures and also work with prefab platforms to shorten site time. Full scope and local pricing are on the ADU Builders in Campbell 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 Campbell
We build conventional structures using James Hardie siding and Tuff Shed-style structures, and we’re fluent with prefab ADU platforms including Abodu and Cover. Parts and materials for these brands are available through our Bay Area suppliers, which keeps turnaround predictable for Campbell jobs. See our brands for the full list.
Pricing for ADU Company in Campbell, CA
| Service | Typical range in Campbell |
|---|---|
| Room addition (400 sq ft) | $120,000 – $160,000 |
| Primary suite addition | $110,000 – $150,000 |
| Second-story addition | $180,000 – $250,000 |
| Attached garage conversion (400 sq ft) | $95,000 – $135,000 |
| Detached garage conversion | $130,000 – $190,000 |
| Carport-to-living-space conversion | $80,000 – $110,000 |
| Detached ADU (400 – 600 sq ft) | $175,000 – $240,000 |
| Detached ADU (600 – 800 sq ft) | $240,000 – $310,000 |
| Attached ADU (JADU-style conversion) | $120,000 – $165,000 |
| Garage conversion to ADU (studio) | $140,000 – $185,000 |
What pushes pricing up in Campbell is usually one of three things: design review cycles near the downtown overlays, foundation retrofit work on older homes, or the need to upgrade the electrical service to carry a second dwelling. Whatever your estimate shows, the number we hand you in writing before work starts is the number on the final invoice.
Neighborhoods We Serve in Campbell
We work throughout Campbell, from the older streets near downtown to the neighborhoods south of Hamilton Avenue and east toward San Tomas. Crews are typically on site in Campbell within a few days of permit approval, and the design review overlay near Campbell Avenue is the one variable that can stretch that timeline.
- Downtown Campbell
- Pruneyard area
- Dry Creek area
- San Tomas neighborhood
- West Campbell
Service Area – Cities Near Campbell
Fielding ADU Builders serves Campbell and the surrounding cities. We also work in Saratoga, CA, Santa Clara, CA, Sunnyvale, CA, and San Jose, CA. One scheduling team covers the whole area, so the pricing and written-guarantee terms are the same no matter which city your project is in.
Serving Campbell, CA - Our Local Coverage Area
We’re based in the Campbell 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 Campbell
Plan on 3 to 6 months for Campbell building and planning approval. Projects near Campbell Avenue or the Pruneyard area often take longer because of design review and neighbor notification requirements. We prepare drawings to address common staff comments before first submittal. Call (669) 201-3984 to get a realistic schedule for your address.
Yes. Every project we take on in Campbell gets a written price before work starts and a written one-year guarantee. If a covered item fails within 365 days, we return at no charge and make it right. That applies to room additions, garage conversions, and ADUs alike.
HOA review is separate from city review, and some Campbell HOAs have their own design rules for ADUs and additions. We include HOA submittal documents in the plan package so you aren’t chasing forms after the city approves. Call (669) 201-3984 and we’ll check what your HOA requires.
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 Campbell Customers Say
"Clear price breakdown. Change orders were all in writing."
- Hal P."Built a detached ADU behind our house. The builder is a veteran and runs the site like a platoon: schedule posted, crew on time, everything labeled. Finished within a few days of the date."
- Ken W."Foundation and slab poured on schedule. Crew kept the yard orderly."
- Marian J.
