Trusted by homeowners across Sacramento & surrounding areas.
Custom ADU in Concord — fast facts
City
Concord
ADU type
Custom ADU
Contractor license
CSLB #1119373
Free estimate
(916) 677-9774
Last updated
Why custom in Concord
When the lot or family won't fit a plan
Most of Concord is flat — 1950s-to-70s tract neighborhoods on valley floor, which sounds like easy ground for a stock plan. It usually isn't. The clay soil moves, the older tracts carry aging electrical panels and tired sewer laterals, and the reason people call us is rarely "I want a generic backyard rectangle." It's a one-off lot or a specific family need. A pool in the way. A second household that needs zero-step access. A unit big enough to actually house two generations. Custom answers what a catalog footprint can't see. We draw the unit to your real parcel, to the engineered foundation the clay demands, and to how your family actually plans to live — then we build it.
Engineered foundation drawn for expansive Concord clay, not a generic slab
Designed around a pool, mature trees, or an odd lot from the first line
The answer when a family need outruns any off-the-shelf plan
The design phase
Site walk to permit, drawn in-house
Custom is won in the drawings, so we put real hours there. It opens with a site walk and a measure-up — in Clayton Valley near Diablo's base, or in one of the flat tracts off Todos Santos. A survey leaves things out. It won't tell you where the sewer lateral actually runs, how old that panel really is, or whether the only equipment path squeezes past a pool. That first visit reshapes the plan and points the foundation engineer at a soil report early, because Concord clay swells and shrinks with the seasons. Then concept sketches. You react, we revise. Most clients run two or three rounds; a few push past five. When the layout locks we draw full construction documents and file with the City of Concord. Honest part: this front end runs six to ten weeks before the counter even sees it.
Site walk plus a check on the panel, lateral, and access before drawing
Soil report drives the foundation from day one on expansive clay
Full construction documents drawn in-house, then filed with the city
Matching the main house
Matching a mid-century Concord home
A custom unit should look like it grew out of your house, not like it got dropped behind it. Concord makes that specific, because so much of the city is postwar tract — low-slung ranch and mid-century homes from the 1950s through the 70s, with wide eaves, shallow roof pitches, and horizontal lines. Drop a tall, steep-roofed box behind a single-story ranch and it fights the street. We pull roof pitch off your actual house, match the eave depth, carry the fascia and trim across, and source siding and a stucco texture that read the same from the curb. Clayton Valley toward the hills runs a little newer and larger; the older tracts near downtown run tighter and lower. A copied stock elevation rarely belongs on either. A drawn one does.
Low-pitch ranch detailing for the 1950s-70s tracts
Slightly larger, newer vocabulary for the Clayton Valley side
Roof pitch, eave depth and trim drawn to your specific home
Multi-gen + finishes
Multi-generational layouts done right
A lot of our Concord custom work is families solving one exact problem — aging parents who want their own front door, or adult kids who'd rather pay into the family than into a Walnut Creek lease. Concord is diverse and multi-generational, and BART-connected, so the demand for this is real. The rent math out here is a different planet from Sacramento, which is why a $400K-plus unit still pencils. That reshapes the plan. We draw zero-step entries, 36-inch doorways, curbless showers with grab-bar blocking in the walls, and a second primary suite so two generations each keep their privacy. The detached ceiling is 1,200 sq ft, and custom clients push right up against it — at that size you fit two real bedrooms, a full kitchen, and a proper living room. Then finish level: quartz, real oak floors, a tiled shower instead of a fiberglass insert.
“Every ADU we build is designed to add long-term value and open new possibilities for your property. Let's build something great together.”
— Tim, ADU Specialist
Custom Designs
Built to fit your property & needs
Turnkey Process
We handle permits, plans & everything
Built to Last
Quality craftsmanship that stands the test
Financing Made Simple
$0 Down Options. Build Now, Pay Over Time.
You shouldn't have to drain your savings to build wealth. We partner with trusted ADU lenders to find financing that fits — many homeowners build with little to nothing out of pocket.
Home Equity (HELOC)
Tap your existing equity at competitive rates — the most popular way to fund an ADU.
Renovation Loans
Finance the build against your home's projected after-completion value.
ADU-Specific Financing
Specialized lenders who underwrite based on the rental income your ADU will produce.
Cash-Out Refinance
Roll the project into a new mortgage and keep one simple monthly payment.
Estimate Your Monthly Payment
See what financing your ADU could look like — and how rental income can help cover it.
$180,000Loan amount
Credit Score
Very good · 700–739
Estimated Monthly Payment
$1,320/mo
At 7.99% APR over 30 years (illustrative)
Often offset by $2,000–$3,500/mo in rental income
No prepayment penalties with most partners
Pre-qualification with no impact to your credit
Illustrative only — not a loan offer. Actual rates and terms are set by third-party lenders based on your qualifications.
Service areas
Where we build
Headquartered in the Greater Sacramento Area and serving homeowners from the Sierra foothills down through the Bay Area. Don't see your city? We probably still get there — just ask.
The most common things Sacramento homeowners ask before starting an ADU project.
Custom is the priciest path, and the Bay Area pushes it higher than almost anywhere we work — I won't soft-pedal it. For 2025-2026 we're seeing finished custom detached units in Concord land roughly $412K to $680K-plus depending on size, finish level, and how rough the site is. A few things drive that. The clay soil means an engineered foundation, not a thin generic slab — real money before you frame a wall. The older tracts often need a main-panel upgrade and sometimes a new sewer lateral, since a 1960s house wasn't wired or plumbed for a second dwelling. Add the Bay Area's high city fees and PG&E coordination. The flip side is why owners build here anyway: Concord rents, with BART access and strong multi-generational demand, run far above Sacramento. Even a $450K-plus unit pencils out in a way it never would back home — and Concord is more affordable to build in than neighboring Walnut Creek.
Fair question, and I'll be straight: we're based in Sacramento, about 70 minutes from Concord. We're not the closest crew you can hire. We extend out here for homeowners who want our craftsmanship and our pricing over a Bay Area outfit's quote, or for a larger custom project that's worth the drive — and custom usually is, because the value sits in the design and the build quality, not in being five minutes away. I'll be on your lot for the site walk and for the foundation pour, the framing, and the key inspections. If your job is a small, simple unit and you want a hyper-local crew, a Concord outfit may serve you fine, and I'll say so. For a complex custom build worth doing right, the right team beats the close one.
A stock plan is pre-drawn and repeated — faster and cheaper, because the design work is done and it drops onto a flat pad. Custom starts at zero for your parcel: our designer sizes and shapes the unit around the soil, the existing pool or trees, the look of your mid-century Concord home, your aging panel and lateral, and exactly how the family plans to live in it. Custom costs more and takes longer up front. The reason to choose it is a one-off problem — a pool in the only open spot, a unit large enough for true multi-gen living, a fully accessible suite, an odd lot shape — that a rectangle off the shelf can't reach. If your lot were a clean open rectangle and your needs ordinary, we'd happily steer you to stock and save you money. With custom, you're paying for the design to solve something specific.
Longer than stock — that's the honest answer, and Bay Area permitting is slower than the Sacramento suburbs we usually work in. Design and construction documents run six to ten weeks. City of Concord review on a clean set commonly runs eight to fourteen weeks, longer if the panel upgrade or lateral pulls in extra review. The build itself is usually seven to ten months for a custom detached unit. Door to door you're looking at roughly twelve to eighteen months. The slower city counter and the utility coordination are what stretch it past a flat-lot Sacramento job — plan for it from the start rather than getting surprised at month four. If a finish has a long lead time, like a specific tile or cabinet line, we flag it early so it isn't what holds up your move-in.
Yes, and it's the part of a flat-lot Concord job people underestimate. The valley floor here is expansive clay — it swells when it's wet and shrinks when it dries, and over the seasons that movement will crack a foundation that wasn't engineered for it. So we don't pour a thin generic slab and hope. We start with a soil report, then design the foundation to the result: often a stiffened, post-tensioned or heavily reinforced slab, sometimes a deepened footing, sized to the clay's plasticity index. It costs more than a casual pour. It's also the difference between a unit that sits flat for thirty years and one that telegraphs cracks through the drywall in year three. On Concord clay, the foundation is where you don't cut corners, and a custom set gets it engineered to your actual lot instead of guessed at.
Often, and on an older Concord tract it's worth checking on day one. A 1950s-to-70s house was wired for that house, not for a second full dwelling with its own kitchen, HVAC, and maybe an EV charger. We do a load calc, and frequently that means a main-panel upgrade so the property can carry the ADU safely. The sewer lateral is the other one — the old clay or cast-iron line running to the street may be near the end of its life, and adding a second unit's flow is a bad time to find that out. We camera or assess it during design when there's any doubt. Neither is a deal-breaker; they're just real line items that a stock-plan quote tends to leave out and a Concord job tends to need. Better you hear it from me up front than at framing.
That's exactly where custom earns its keep. A stock rectangle assumes an open, empty backyard. Real Concord lots have a pool in the obvious spot, a mature shade tree you don't want to lose, or an odd lot line that the standard footprint runs straight into. Custom designs around all of it. We site the unit to keep the pool usable and meet the setback off it, draw the footprint to preserve the trees worth keeping and their root zones, and shape the building to the buildable area you actually have rather than the one a catalog assumed. On a flat tract lot, that's most of the reason to go custom — the ground is fine, it's the stuff already on it that a pre-drawn plan can't account for. We map all of it on the first site walk.
The permit goes through the City of Concord — it's the largest city in Contra Costa County and runs its own building and planning departments, so plan check and inspections are city, not county. One counter. Power is PG&E. A custom unit's electrical service, any main-panel upgrade, the load calc, and the meter set all coordinate through PG&E, which in the Bay Area can be slow. If you've heard of SMUD from family in the Sacramento area, it doesn't operate here. An all-electric unit with a heat pump, an induction range, and maybe an EV charger pulls real load, so we size the service and line up PG&E early in design rather than at the end, where it stalls a final inspection. Getting the utility piece moving early is half of keeping a Concord custom build on schedule.
State law caps a detached ADU at 1,200 sq ft, and most of our custom clients build right up near that ceiling — at 1,100 to 1,200 sq ft you fit two genuine bedrooms, a full kitchen, and a real living room, which is usually the whole point of going custom and the whole point of multi-gen living. Whether your Concord lot has room to site a unit that size depends on the parcel and what's already on it. A wide flat tract backyard takes it easily; a lot with a pool, a tight side yard, or trees you're keeping gets carved down by setbacks and what you want to preserve. Smaller is allowed; we just rarely see custom clients want it. Attached ADUs follow a different size rule tied to the main house, so if you're attaching to a ranch we'll run those numbers for your specific lot.
In-house. Our designer does concept, floor plans, elevations, and the full construction document set, and that same drawing carries straight into the build with no handoff gap. You're not coordinating a separate architect, a separate soils engineer, and a separate builder who all point fingers when the clay report comes back or the city kicks comments. One team owns the design and owns the result — which matters on a Concord custom job, where the foundation engineering, the panel and lateral calls, and the back-and-forth with the city counter are constant, and someone needs to own them end to end. That's also part of how we keep a Bay Area build at a price that makes sense from a Sacramento base.
Other services
Not quite the right fit?
Every Sacramento ADU project is different. Here are the other paths we build under one roof — and we're happy to talk through which one fits your lot best.
We treat every home like it's our own — quality work, clear communication, and happy homeowners.
PaulOwner · Future Generation
9 min read2,081 words8 sections
Custom ADU design and construction in Concord
Some Concord backyards look easy — flat valley lots, postwar tracts — and still won't take a stock plan. A pool sitting in the only open spot, an odd lot line, a 1960s house with a tired panel, expansive clay underneath, or parents moving in who need a unit drawn around them: that's when you build custom. We're a Sacramento design-build crew (CA license #1119373) that extends to the East Bay for owners who want our craftsmanship and value, draws a bespoke ADU for your exact Concord lot, and builds it design through final inspection, one team the whole way. Call (916) 677-9774.
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What actually makes an ADU custom
People throw "custom" around loosely, so let me draw the line. A stock or model ADU is a plan we've already drawn and built before — pick a size, maybe swap a finish, and it drops onto a flat pad. Quickest, cheapest, and for a clean open Concord backyard with an ordinary main house, often the right one. We build those gladly. But it isn't custom.
Custom means the design starts at zero, on your parcel. Our designer takes the survey, the City of Concord setbacks, the soil report, the pool or trees already in the yard, the age of your panel and lateral, and how your family plans to live. Then a unit gets drawn that didn't exist until your lot called for it. The footprint bends around what's there, the foundation answers the clay, the roofline answers your house. Nobody else has this plan.
