Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Upland
Home additions and ADUs in Upland typically run $45,000-$130,000 for an addition and $90,000-$220,000 for a detached ADU, with timelines set less by labor and more by design approvals, fault-zone studies where they apply, and long-lead finishes. If you live in the 91784 foothills, your address may sit inside the Alquist-Priolo Earthquake Fault Zone, which changes the permit path before a single footing is poured. Our Home Additions & ADU team handles that conversation daily, and we won’t let it surprise you mid-project. Call (877) 610-1318 and we’ll walk your specific lot, not a brochure.
We’ve been building in Upland long enough to know that Euclid Avenue traffic at 5 p.m. means our crew leaves the shop early or not at all, that a 1972 tract house on a slab in 91786 needs different detailing than a 1998 custom home on a slope in 91784, and that the city’s planning counter asks questions no flatland contractor in Ontario prepares for. That’s the advantage of a local, owner-operated company: the name on the truck is the name on the permit.
Why Barrett & Sons Construction Is Upland’s Preferred Home Additions & ADU Company
Tom Barrett started Barrett & Sons in 1998, and his sons still run the crews. When you call about an addition or ADU in Upland, you’re not routed to a call center in another state. A live person answers, 24/7, and that person works a few miles from your job site. Tom publishes his name, his address, and his license number. Look it up before you sign anything. That’s the whole point.
Upland homeowners come to us for the same reasons their neighbors do: every price change arrives as a written change order before work proceeds, permits get pulled and inspections get signed on every eligible job, and the 90-Day Done Right Promise is written into the contract. Not a verbal promise. A written guarantee. If something isn’t done right, Tom comes back and makes it right on one call. We install premium brands you can look up: Cambria countertops in kitchens, Kohler fixtures in baths, Andersen windows on additions. No mystery materials off a van.
We also know that Upland isn’t one housing market. South of the 10, it’s post-war slab-on-grade tract homes. North of the 210, it’s hillside custom builds on alluvial fans. The permit path, the engineering, and the schedule are different in each. A contractor who treats 91786 and 91784 the same way is the one who gets stuck at plan check.
Our Home Additions & ADU Services in Upland
ADU Design & Permitting
Before we talk square footage, we talk site conditions. In Upland’s 91784 ZIP, that means checking whether your parcel falls inside or adjacent to the Alquist-Priolo study zone for the Cucamonga Fault. If it does, the state mandates a fault-rupture study before the city will approve your ADU permit. We coordinate the geologist, the city, and the architect so that step doesn’t blindside you. On flatland lots in 91786, the conversation shifts to side-yard setbacks, utility panel capacity, and zoning under Upland’s ADU ordinance. Either way, the permit inspector works for you, not for me. We like him there.
Garage Conversion ADU
Upland’s 1950s and 1960s tract homes in 91786 often have attached garages built as slab-on-grade without perimeter footings designed for living space. Converting one to an ADU usually means adding foundation support, insulation, and a mechanical system, not just drywall and paint. We scope all of that in writing before demo day. If the slab has settled or cracked from Upland’s expansive soils, that gets addressed in the same permit package, not discovered later as a change order.
New Detached ADU
A new detached ADU in Upland’s foothills is a different animal than one in Claremont’s flatlands. Sloped alluvial-fan lots in 91784 routinely require engineered grading plans, retaining walls, and hillside-specific framing. We budget for that from day one, along with freeze-condition flashing that flatland contractors rarely think about. On a typical detached ADU in Upland, you should plan $90,000-$220,000, with the higher end reflecting hillside work, designer finishes, and utility trenching. We’ll put the number on paper before you commit to anything.
Junior ADU & Interior Conversion
For homeowners in north Upland who don’t want to touch their lot line, a junior ADU inside the existing envelope can work. It’s usually a converted bedroom with a kitchenette and private entrance, and it moves through Upland’s building department faster than a ground-up build. The catch: the existing house has to have the electrical service and water heater capacity to support it, and we verify that before the plans are drawn. A JADU that trips breakers every time someone uses a toaster isn’t an ADU, it’s a problem with walls.
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.
Trusted Brands We Service in Upland
We carry and install premium windows and doors from Simonton, Ply Gem, and PGT across every Upland addition and ADU. That matters more in Upland than most places: the Santa Ana winds that funnel down from the San Gabriels put real pressure on glass and seals. Cheap windows lose their argon fill and fog up. We won’t install them. We also stock the local trim profiles and hardware that match Upland’s older housing stock, so a second-story addition on a 1963 Cambridge Circle home doesn’t look like it was stapled on from a catalog. Parts arrive from our Inland Empire warehouse, not a warehouse in Ohio.
Common Home Additions & ADU Problems We See in Upland Homes
- Fault-zone surprises in 91784. A homeowner buys a lot or plans an addition without a pre-offer fault-zone check, then the city requires a mandatory Alquist-Priolo study. That can add weeks and thousands before a footing is poured. We run this check early, every time.
- Designer finishes without fixed-price allowances. You pick a Cambria slab for the kitchen and Kohler fixtures for the bath, but the allowance wasn’t locked in writing. The change order lands, and your budget breaks. Our rule: an allowance that isn’t on paper is a surprise waiting for a date.
- Hillside retaining walls and freeze flashing left out of the bid. North Upland lots on alluvial fans frequently need retaining walls and cold-weather detailing that flatland bids omit. By the time it’s caught, the project is exposed and the budget is shot. We scope it before the first inspection.
- Slab-on-grade foundation limits on garage conversions. South Upland’s 1950s and 1960s tract homes sit on slabs that were never designed to carry living space. Converting a garage without addressing the slab invites cracks, moisture, and a failed inspection. We include the foundation work in the original scope, not the change order.
Pricing for Home Additions & ADU in Upland, CA
Here is what we’re seeing in Upland right now. These are installed prices, not bare-labor numbers, and they reflect our market, not a national average.
| Project | Typical Upland Range |
|---|---|
| Home Addition | $45,000-$130,000 |
| ADU Construction | $90,000-$220,000 |
| Kitchen Remodel | $14,000-$45,000 |
| Bathroom Remodel | $9,000-$28,000 |
The spread is real, and it’s driven by three things: whether your lot triggers fault-zone or hillside grading requirements, the level of designer finishes you choose, and whether you’re converting or building new. A flatland garage conversion in 91786 lands near the bottom. A custom second-story addition in 91784 with Cambria countertops, PGT windows, and engineered shear walls lands near the top. Whatever your number is, it gets fixed in writing before we order materials, and it only changes if you sign a written change order. Call (877) 610-1318 for a free estimate with line items, not hand-waving.
We Also Serve Cities Near Upland
Our crews work throughout the foothills and the valley floor. In addition to Upland, we serve Claremont, Montclair, Rancho Cucamonga, and Ontario. Same people, same trucks, same written change orders, same 90-Day Done Right Promise. If you live on the border where Upland meets Claremont off Foothill Boulevard, don’t worry: we cover both sides of the street.
Serving Upland, CA - Our Local Coverage Area
We’re based in the Upland 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 Upland
No. The requirement only applies to parcels that fall inside or immediately adjacent to a mapped Alquist-Priolo Earthquake Fault Zone, which runs along the mountain front in north Upland’s 91784 ZIP. Flatland lots in 91786 are not in the zone. We check your parcel against the fault-zone map at the start of every Upland project so you know what you’re facing before plans are drawn. If a study is required, a state-licensed geologist does the trenching and the report, and we coordinate it as part of the permit package. Call (877) 610-1318 and we’ll check your address for free.
Lead times, not labor, set the calendar. Designer finishes, custom cabinetry, architectural glass, and specialty tile all have their own production schedules. A set of Wellborn cabinets can take six to ten weeks to clear; a custom PGT window package can sit at the factory for a month. Ontario flatland builds with builder-grade finishes avoid those waits. Upland hillside home-owners who want Cambria and Kohler do not. We sequence the job around those lead times and hold the draw schedule accordingly, so nobody is paying for materials that haven’t shipped. The schedule is written down, and so is the price.
Every allowance is written into the contract as a fixed dollar amount before any materials are ordered. If you pick a $2,200 Cambria slab and the allowance is $2,200, you’re done. If you pick a $3,600 slab, you sign a written change order for the difference before the slab gets fabricated. The allowance that isn’t on paper is a surprise waiting for a date. We publish the allowance schedule with your initial estimate, so there’s no mystery line item at the end.
In nearly all cases, no. Most of Upland’s 1950s and 1960s garage slabs in 91786 are unreinforced and sloped for drainage, not designed for finished living space. Converting one to an ADU usually requires added footings, a capillary break, and insulation. We include that in the original permit scope, not a change order. Our crew just wrapped a second-story addition on a 1970s custom hillside home in 91784, coordinating with the architect on load-bearing shear walls and engineered grading plans before ordering Cambria countertops and Kohler fixtures. The rough-in passed inspection sign-off on the first visit, and we held the draw schedule while long-lead cabinetry from Wellborn cleared customs. That’s how it should go.
Draws follow milestones, not calendar days. Typically: a deposit at contract signing to lock in design and long-lead materials, a draw at permit approval, a draw at foundation and rough-in, a draw at drywall, and a final draw at inspection sign-off. On a $150,000 ADU in 91784, the deposit is usually in the 20% range because we’re ordering PGT windows and Cambria surfaces early. The draw schedule is written into the contract before you sign, and no draw is requested before the milestone is actually complete. That protects you, and it keeps the job honest. Call (877) 610-1318 for an exact draw schedule on your project, free.
Your Next Step
You’ve read this far, which means you’re probably weighing a real project and want real numbers. Good. Call Tom and the team at (877) 610-1318. We’ll walk your Upland lot, check the fault-zone map, look at your panel and your slab, and hand you a written estimate with line items, allowances, and the draw schedule included. No trip charge inside the county. If you’ve already got a written estimate from someone else, bring it in for a free second opinion. If you’re 65 or older or a veteran, the 10% discount applies. Let’s talk before you sign anything.
Written by Tom Barrett, Owner at Barrett & Sons Construction. Tom founded the company in 1998 and still walks job sites in Upland personally.