Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Davis
A home addition or ADU in Davis typically runs $45,000 to $130,000 for an addition, and $90,000 to $220,000 for a full detached ADU. The range hinges on what Davis plan check is going to ask of your drawings, and that extra step catches a lot of out-of-town contractors flat-footed. We’re Barrett & Sons Construction, and we’ve been pulling permits in this city long enough to know exactly what that green-building review demands before we ever submit. Call Tom Barrett at (877) 610-1318 and you’ll get a straight answer on your project, not a voicemail.
Why Barrett & Sons Construction Is Davis’s Preferred Home Additions & ADU Company
Davis isn’t like Woodland or Dixon when it comes to construction paperwork, and we don’t treat it like it is. The city runs every addition and ADU through a local green-building ordinance that sits on top of Title 24. That’s an extra energy-modeling review, an extra plan-check round, and an extra chance for a cheap bid to stall out. We know the people at the counter, we know what the inspector checks first, and we’ve been through enough Davis plan checks to know which details get a red line and which ones sail through.
Homeowners here have also had their fill of contractors who quote low and then “discover” change orders once the footing is open. Every scope, every allowance, every price change we make arrives as a written change order before a single nail moves. And because Tom Barrett lives close enough to run into you at the Davis Farmers Market, we’re not going to disappear if something needs fixing after sign-off. Our 90-Day Done Right Promise is printed on the contract, not whispered at the estimate.
One more thing: we answer the phone. Not a call center in another state, not a “we’ll get back to you.” A live person, 24/7, every day. When a Davis homeowner calls about a stalled plan check or a crack in a new slab, they talk to someone who knows what that means here.
Our Home Additions & ADU Services in Davis
ADU Design & Permitting
This is the service where Davis’s green-building ordinance does its real work. Before drawings go to the city, they have to go through an energy model that proves the unit meets the local standard, and that’s on top of what California already requires. We handle that modeling in-house, submit drawings that are ready for that review, and shepherd the permit through plan check so your timeline doesn’t stall. Most people don’t realize that a rejected energy model can add six to eight weeks to a Davis ADU project. We’ve seen it happen to owners who hired designers from outside Yolo County.
New Detached ADU
A detached unit in 95616 or 95618 typically means new footings, new utility trenching, and a foundation spec that accounts for Davis’s clay. The shrink-swell cycle here is real: the soil drinks winter rain and cracks hard in 100-degree summer heat, and a slab that isn’t engineered for that movement will crack within two dry seasons. We over-excavate, compact, and post-tension where the soil report calls for it. That’s not an upgrade in Davis; it’s the minimum if you want the slab to hold its line.
Garage Conversion ADU
Converting an attached garage in Davis runs $30,000 to $80,000 depending on what’s already under the concrete and whether the roof meets current wind-load standards. Our crew has converted garages across 95616, and in the older ranch neighborhoods we typically find original slabs too thin for living space, so we saw-cut, add perimeter footings, and re-pour to code. If you’re in Village Homes, we also check the original passive-solar details before we touch a wall. Clerestories and bermed walls don’t always play nice with standard conversion plans.
Junior ADU & Interior Conversion
A JADU taps into space you already have, usually a spare bedroom or an oversized utility room off the main house. These projects in Davis run lower than a detached build because there’s no new foundation and no new utility service drop. But they still get the same green-building screen, and a lot of 1950s and 1960s stock in central Davis has knob-and-tube or ungrounded panels that need remediation before the city will sign off. We price that work up front. It’s not a surprise when the permit comes back with a correction.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Davis
We carry materials you can actually look up, not whatever fell off a van. For additions and ADUs, that means Schluter waterproofing systems in wet rooms, Grohe fixtures where you want something made in Germany rather than somewhere cheaper, and GAF roofing when the addition ties into the existing roof and has to meet wind-load requirements under a Davis inspection. We stock common parts locally so a punch-list item on a Davis job doesn’t wait on a backorder from three states away. It’s the same reason we use GAF underlayment on roof tie-ins: when the inspector wants to see the data sheet, it’s already in the permit packet.
Common Home Additions & ADU Problems We See in Davis Homes
- Shrink-swell cracks in post-tensioned slabs. On a slab-on-grade ranch in 95616, we cut a load-bearing wall to open the kitchen into a new sunroom, and our crew hit the classic Davis shrink-swell crack in the original post-tensioned slab. We had to pull a change order to dowel and epoxy new rebar into the existing foundation, schedule an inspection sign-off on the rough-in before the pour, and keep the concrete work before 10 a.m. to beat the summer heat.
- Green-building plan check rejections. We’ve lost count of ADU permit packages sitting in Davis plan check because an out-of-market contractor skipped the local energy model and figured Title 24 was the bar. It isn’t. That one miss can add two months to your timeline and a re-draft fee on top of it.
- Footing failures on adobe clay. You pour a standard footing in a Davis backyard because it looked fine on the soil map, and by the second dry season the doors stick and the corner of the addition drifts. The right spec here either drops the footing deeper or post-tensions the slab, and a cheap quote never includes it.
- Village Homes drainage conflicts. In the northwest, the original 1970s lots slope toward shared swales that handle stormwater. Build an addition over or against one without coordinating with city planning, and you’ve just redirected runoff into your neighbor’s yard. That’s a costly redesign, and it’s one of the easiest mistakes to avoid by pulling the site plan before the architect starts drawing.
Pricing for Home Additions & ADU in Davis, CA
Here’s where your money actually goes in Davis, and the numbers are built for this market, not pulled from a national average.
| Project Type | Typical Davis Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
A $45,000 addition on the low end is a small bump-out or a single-room sunroom with basic finishes. The $130,000 end gets you a substantial second-story addition with structural steel, a full tie-in to the existing roof, and windows that clear Davis’s energy standards without issue. For an ADU, the spread comes down to whether you’re doing a garage conversion, a detached new build with site utilities, or a custom-designed unit on a Village Homes lot that needs overtime on planning coordination. Every estimate we hand you in Davis includes permits pulled, inspections signed, and a written scope so the number on your contract is the number you pay. Call (877) 610-1318 for a free, no-trip-charge estimate inside Yolo County.
We Also Serve Cities Near Davis
Our crews are on the road every week serving Davis plus Dixon, Woodland, West Sacramento, and Winters. If you’re just outside the city line, the permit rules change the minute you cross into a different jurisdiction, and we know which ones ask for what. The same Home Additions & ADU team handles the whole loop, so you’re not getting a different crew just because the job is 15 minutes north.
Serving Davis, CA - Our Local Coverage Area
We’re based in the Davis 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 - Home Additions & ADU in Davis
Yes. Every permitted addition and ADU in Davis goes through the local green-building review on top of Title 24, regardless of square footage or whether the unit is attached, detached, or converted. The main variable is which compliance path applies, and we run the energy model as part of the design phase so your drawings don’t come back from plan check with a rejection. Call (877) 610-1318 and we’ll walk you through which standard applies to your lot.
A second-story addition in Davis must be engineered for the wind zone set by the current California Building Code, and yes, that flows straight into the roof tie-down and shear-wall spec on your plans. The engineering letter we attach to your permit package will call out the exposure category for your specific lot, and we run the tie-downs up through the new top plate into the existing roof structure. A cheap quote that leaves “roof tie-down” off the line items isn’t a compliant quote.
It will, but only if it’s documented. When we finish the wind-load upgrades and the energy-model compliance on your ADU or addition, the final inspection record, the engineering letter, and the permit close-out form a paper trail you can hand to your insurer. That’s the difference between a claim adjuster accepting the work as code-compliant or flagging it as an unpermitted modification. We keep all of it in a folder for you, whether the insurance question comes up now or in ten years. For specifics on your policy, call your agent, and call us at (877) 610-1318 if they ask for documentation you don’t have.
Yes, in most cases you can, but the siting has to be coordinated with city planning because the original Village Homes layout runs shared drainage through the lots in a way standard residential parcels in Davis don’t. We’ve built around those swales by shifting the ADU footprint, raising the finished floor, or re-routing drainage with the city’s sign-off. That coordination takes time, and we factor it into the permit schedule up front, because discovering it at excavation is when budgets break.
We start with a soil report that quantifies the expansion potential, then we over-excavate the bad material, import engineered fill where the report calls for it, and post-tension the slab when the geotech recommends it. That’s the standard in Davis, not an extra. Contractors who skip the soil report and pour a conventional slab are the reason you see doors misaligning in Davis additions two summers after the job closes. Call (877) 610-1318 and we’ll tell you what your lot needs before we ever quote the number.
Get Your Home Addition or ADU Started in Davis
If you’re planning an addition or ADU in Davis, get a contractor who already knows what the city is going to ask before the plans even go in. Tom Barrett and his sons run the crews, the permits get pulled on every eligible job, and every price change arrives in writing before any work begins. Call (877) 610-1318 today for a free estimate, or ask us to take a second look at a written estimate you already have. No trip charge inside Yolo County, and a live person answers the phone.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Davis and surrounding Yolo County communities since 1998.