A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Lafayette, CA
Benson ADU Builders handles accessory dwelling unit construction and home additions in Lafayette, where hillside lots, protected oaks, and geotechnical requirements make every project a little more involved than a standard flatland build. Lafayette homeowners running an ADU project here face terrain and permitting realities that don’t show up in neighboring Contra Costa cities. We put the full price in writing before work starts and build with brands like Plant Prefab, Boxabl, and James Hardie. Call (424) 328-5746 to talk through your lot.
Why Lafayette Homes Are Different
Lafayette’s housing stock leans heavily toward single-family homes built from the 1950s through the 1970s, many of them ranch and split-level designs with wood framing and stucco or siding exteriors. Hillside construction across the city regularly uses pier and grade beam foundations, which changes how an ADU gets anchored and adds cost you won’t see on flat lots one town west.
The terrain is the real differentiator. Lafayette enforces strict hillside development standards, and lots in Happy Valley and Burton Valley often carry protected oaks or seasonal creeks. Once an arborist report and setback review are in hand, a footprint that looked generous on paper can shrink by half. Homeowners who plan for that from the first conversation make faster decisions; those who don’t lose months in design revisions.
Climate plays in too. Hot, dry summers followed by cool, wet winters mean waterproofing details and fire-resistant materials matter, especially on hillsides with wildfire exposure. Expansive clay soils across many Lafayette parcels shift with moisture, so foundation and drainage choices have to be right the first time. We factor all of that into the written price instead of discovering it mid-project.
Our Main Lafayette Services
Most Lafayette homeowners come to us for one of three projects. Each has its own dedicated Lafayette page with local pricing and detail, linked below.
ADU Builders in Lafayette
A Lafayette ADU typically means a detached unit or garage conversion on a hillside or large lot, with extra engineering for slopes, soils, and protected trees. We walk each site before quoting, then give you a written price tied to your actual lot conditions, not a generic square-foot multiplier. That matters on Lafayette hillsides, where foundation work can swing the budget more than any other line item. See the full scope and pricing on our ADU Builders in Lafayette page.
Home Addition Contractor in Lafayette
Home additions in Lafayette often attach to a 1960s ranch or split-level, which means matching rooflines, tying into aging framing, and sometimes upgrading the existing structure to current code while we’re in the wall. Hillside additions carry more foundation work; flatland additions carry more kitchen and living-space reconfiguration. Either way, the addition has to look like it was always there. Get the full breakdown on our Home Addition Contractor in Lafayette page.
Room Addition Contractor in Lafayette
A room addition is the most focused project we take on in Lafayette: one bedroom, an office, a family room bump-out. These jobs move faster than full ADUs but still hit the same Lafayette-specific issues: protected oaks near the addition, lot setback constraints, clay-heavy soils. We handle everything from paperwork to finish, with a written price before any work starts. Read the full scope on our Room Addition Contractor in Lafayette 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 Lafayette
For Lafayette projects we work most often with our brands including Plant Prefab, Boxabl, and James Hardie cladding. These names give you something concrete to research before signing, and local stocking keeps lead times predictable across the Bay Area.
Pricing for ADU Company in Lafayette, CA
| Service | Typical range in Lafayette |
|---|---|
| Detached ADU (1 bed / 1 bath, 450 – 600 sq ft) | $185,000 – $265,000 |
| Detached ADU (2 bed / 1 bath, 650 – 850 sq ft) | $245,000 – $340,000 |
| Garage conversion ADU (existing structure) | $95,000 – $165,000 |
| JADU (junior ADU inside existing home) | $75,000 – $120,000 |
| Prefab ADU (Boxabl or Plant Prefab, turnkey) | $160,000 – $240,000 |
| Whole-home addition (400 – 600 sq ft) | $175,000 – $265,000 |
| Primary suite addition (300 – 450 sq ft) | $135,000 – $200,000 |
| Room addition (single room, 200 – 300 sq ft) | $85,000 – $145,000 |
| Second-story addition (400 – 500 sq ft) | $220,000 – $310,000 |
| Site prep, grading, and slope remediation (hillside lots) | $20,000 – $65,000 |
Lafayette hillsides push prices higher than flatland Contra Costa builds, mostly because of pier and grade beam foundations, geotechnical reports, and oak tree protection requirements. Whatever the number, it’s in writing before we start. That’s the whole point.
Neighborhoods We Serve in Lafayette
Our crews cover the full city, including these Lafayette neighborhoods:
- Happy Valley
- Burton Valley
- Downtown Lafayette
- Reliez Valley
- Silver Springs
Response time across Lafayette is typically same-week for site visits, with weekend slots available for homeowners who can’t step away during the workday.
Service Area – Cities Near Lafayette
Benson ADU Builders also serves homeowners in nearby Bay Area cities, including Piedmont, CA, Albany, CA, Berkeley, CA, and Hercules, CA. Dispatch and scheduling are coordinated from our San Francisco Bay Area office, with crews serving Lafayette locally.
Serving Lafayette, CA - Our Local Coverage Area
We’re based in the Lafayette 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 Lafayette
Most Lafayette homeowners get a site visit within the same week they call, often within two business days. We schedule Saturday walkthroughs for people who can’t take time off work. Call (424) 328-5746 and we’ll get you on the calendar.
Yes, and that’s where Lafayette differs from flatland cities. Hillside lots commonly trigger geotechnical review, arborist reports for protected oaks, and creek setback checks. We handle the paperwork and build those costs into your written price up front.
No. The Relay Visibility Guarantee means you get a written price before any work begins, and that price doesn’t move unless you change the scope. If a covered repair fails within 365 days, we come back and make it right. That’s in writing on every project.
Ready to price your Lafayette project? Call Benson ADU Builders at (424) 328-5746 for a free estimate and a written quote you can actually plan around.
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 Lafayette Customers Say
"Solid job. Cabinets arrived late but they adjusted the schedule."
- Eli K."Plumbing and electrical passed on the first inspection."
- Alan B."Communication was the best part. I always knew what was happening that week without having to ask."
- Dolly N.
