A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Alamo, CA
We’re Sutton ADU Builders, the ADU and home-addition contractor serving Alamo homeowners who want straight answers before any tool is lifted. Most Alamo lots are large, most homes are wood-frame ranch or custom builds from the 1950s through the 1980s, and most projects we quote here are detached ADUs or additions that take advantage of generous setbacks. You’ll get a written price before work begins, a 365-Day Done Right Promise in writing, and a photo-badged crew whose names you’ll know before they arrive. Call (831) 272-7212 to talk through your property.
Why Alamo Homes Are Different
Alamo sits in an unincorporated pocket of Contra Costa County, which shapes how ADU and addition projects actually move through permits. There’s no Alamo city building department. Plan review goes through the county, so timelines run differently than in neighboring incorporated cities, and the inspectors you’ll meet are county inspectors. We plan for that from day one, and we tell you what it means for your schedule before you commit.
The housing stock matters too. Alamo is dominated by single-story ranch and custom homes on half-acre to multi-acre lots, most built between the 1950s and 1980s with wood-frame construction. Those wide lots leave room for a detached ADU without crowding the main house. Hot, dry summers and mild, wet winters also push many homeowners toward designs that connect indoors to shaded outdoor living space, and fire-resistant materials like James Hardie cladding come up often in our Alamo conversations. Some of the larger rural lots still run on older septic systems, and that single condition can add real cost and time before county approval ever happens. We flag it early because you deserve to know before you’re months in.
Our Main Alamo Services
Most Alamo homeowners reach out to us about one of two things: adding square footage to the existing house, or building a detached ADU on the lot. Here’s how each one works in Alamo specifically.
Home Addition Contractor in Alamo
A home addition in Alamo usually means extending a ranch home outward, which works well on the wide lots here. You might be adding a primary suite, a family room, or a larger kitchen. Because so many Alamo homes are wood-frame builds from the 1950s to 1980s, we look carefully at the existing foundation and roofline before pricing, and we write what we find into the quote so there are no surprises later. County permit review applies here too. See our full Home Addition Contractor in Alamo page for what the build process looks like on your street.
ADU Builders in Alamo
Detached ADUs are a natural fit for Alamo’s half-acre and multi-acre lots, and unincorporated zoning here tends to give you more design room than some neighboring cities. We work with prefab and modular brands like Abodu, Cover, and Plant Prefab, plus traditional stick-built ADUs, and we’ll tell you honestly which route fits your lot, your septic situation, and your budget. County plan review and inspections apply. Our ADU Builders in Alamo page walks through pricing and the build timeline in more detail.
Room Addition Contractor in Alamo
A room addition means one new space, often a bedroom, office, or expanded living room, tied into the existing roofline. In Alamo, those projects usually move faster than full additions because the scope is tighter, but the county permit path is the same. We price the job with a written, line-by-line quote before work starts, and the 365-Day Done Right Promise covers the finished work for a full year. Details are on our Room Addition Contractor in Alamo 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 Alamo
We have direct experience with Abodu, Cover, and Dvele ADU systems, plus Tuff Shed structures and James Hardie exterior cladding. That means we can give you honest guidance on which product line actually fits your Alamo lot and budget, not a sales pitch for one brand. See our brands for the full list.
Pricing for ADU Company in Alamo, CA
| Service | Typical range in Alamo |
|---|---|
| Detached ADU (under 500 sq ft, prefab) | $140,000 – $230,000 |
| Detached ADU (500 – 800 sq ft, panelized/prefab) | $200,000 – $320,000 |
| Detached ADU (800 – 1,200 sq ft, custom build) | $300,000 – $480,000 |
| Garage conversion to ADU | $110,000 – $200,000 |
| Tuff Shed conversion to ADU | $90,000 – $160,000 |
| Primary suite addition | $130,000 – $230,000 |
| Family room or kitchen extension | $150,000 – $280,000 |
| Single room addition (bedroom/office) | $90,000 – $160,000 |
| Septic system upgrade (large rural lots) | $25,000 – $60,000 |
What pushes cost up in Alamo is usually the lot itself: a failing septic system on a rural parcel, unusual slope, or a foundation that needs reinforcement before we build. Every quote is a written, line-by-line price delivered before any work starts, and it doesn’t change unless you change the scope.
Neighborhoods We Serve in Alamo
We cover the whole Alamo area, from the neighborhoods around Stone Valley Road and Danville Boulevard to the quieter streets closer to the Las Trampas ridge. If your lot is in unincorporated Contra Costa County with an Alamo mailing address, we serve you.
- Stone Valley Road corridor
- Danville Boulevard area
- Alamo Springs and surrounding hillside streets
- Livorna Road and Miranda Avenue area
For most Alamo properties, we can schedule an on-site walkthrough within a couple of weeks of your call, and we’ll give you the name and photo of who’s coming before they arrive.
Service Area – Cities Near Alamo
We also work in nearby East Bay communities, including Walnut Creek, CA, Pleasant Hill, CA, Alameda, CA, and Benicia, CA. If you’re on the edge of Alamo and aren’t sure which service area you fall in, call us and we’ll sort it out.
Serving Alamo, CA - Our Local Coverage Area
We’re based in the Alamo 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 Alamo
Alamo is unincorporated, so there’s no city building department. Your ADU or addition permit and inspections go through Contra Costa County, which means county timelines and county inspectors. We handle the paperwork and tell you what to expect before you sign.
Call (831) 272-7212 for a free estimate on your project.
On many of Alamo’s larger rural lots, yes. Older septic systems often can’t handle a second dwelling’s additional load, and the county may require an upgrade before approval. We assess this early so you know the true cost before you commit.
Call (831) 272-7212 to talk through your lot.
It covers defects in workmanship for one full calendar year from project completion, in writing. If something isn’t right, we make it right, including a free second visit if a repair or build element fails. No haggling, no fee.
Call (831) 272-7212 for a free estimate. We’ll price your Alamo project in writing before any work begins.
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 Alamo Customers Say
"Straight answers on what we could and couldn't do on our lot."
- Edwin H."Every crew member was vetted and carried a badge, which matters when they are around your family for months. Tidy site every day."
- Daniel F."Insulated the walls and ceiling properly. It stays comfortable even in July."
- Tamika W.
