







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across Redlands
Most detached ADUs in Redlands run between $180,000 and $320,000 before site work, and the permit process typically takes four to eight months depending on whether your lot triggers floodplain review. That’s the honest range, and it’s the number you should have in your head before you start calling builders. Our crews know Redlands block by block, from the Historic District south of downtown to the newer tracts off San Timoteo Canyon Road and Sunset Drive. If you’re weighing a backyard unit, a garage conversion, or a room addition, call Miles Hartwell and the Sutton team at (472) 248-8213 for a written price before a single tool is lifted.
Why Sutton ADU Builders Is Redlands’s Preferred ADU Builders Company

Sutton ADU Builders is part of the Threshold Group family, founded in 2006, and every Redlands project we take runs on the Threshold Standard. That means a written price delivered before work starts, a 365-Day Done Right Promise covering workmanship for a full calendar year, and a free second visit if any element fails. It’s not a verbal assurance. It’s stamped on your project paperwork.
What Redlands homeowners tell us they value most is knowing exactly who shows up. Every Sutton technician is background-checked, identity-verified, uniformed, and photo-badged. We send you the name and photo of the crew lead before the visit. You’ll open your door to a person you’ve already seen, not a truck full of strangers. For homeowners who are often alone, parents with young kids, or older residents, that proof matters more than a low bid.
We’ve worked on detached units behind 1920s bungalows near Cajon Street and Olive Avenue, on garage conversions in the neighborhoods east of the University of Redlands, and on backyard units in South Redlands where citrus-era lot lines don’t run square. That local experience means we don’t get surprised by the things that surprise out-of-town builders.
ADU Design in Redlands
ADU Design in Redlands means drawing a unit that actually fits your lot, your setbacks, and the city’s design review rules, not pulling a stock floor plan off a shelf. A well-scoped design package for a detached ADU in Redlands typically runs $8,000 to $18,000 depending on whether you need structural engineering, floodplain elevation work, or historic-district design review. Homeowners who skip this step and buy an unmodified prefab kit often end up paying more in plan-check revisions than the design would have cost in the first place.
Setbacks, Lot Coverage, and Citrus-Era Quirks
A setback is the required gap between your new structure and the property line. On Redlands’ older lots, those lines don’t always match the fence you’ve been mowing along for twenty years. We survey first. We check lot coverage against any unpermitted shed or old garage the city may count against you.
Historic District Design Review
If you’re within the Redlands Historic District, your ADU has to pass design review with the city’s preservation staff before plan check clears. That means rooflines, siding materials, and window proportions matter. Our team has matched James Hardie siding and period trim on units behind 1920s homes, which keeps the review moving instead of stalling.
Backyard ADU in Redlands

Backyard ADU construction in Redlands is the most flexible way to add rentable square footage or space for family, but the sitework costs here are real. A 600-square-foot detached unit with standard finishes typically lands between $210,000 and $310,000 in Redlands once you account for foundation work, utility connections, and the city’s floodplain and drainage requirements. The price moves most on what’s under the dirt, not what’s above it.
Foundation and Floodplain Considerations
Redlands sits within the Santa Ana River watershed, and much of the residential grid falls in the San Timoteo Creek and Santa Ana River floodplain. Projects in these zones often require a floodplain elevation certificate showing the finished floor sits above the base flood elevation the city requires. That’s an extra survey, an extra review step, and sometimes a raised foundation or fill plan. Neighboring foothill cities don’t ask for any of it.
Old Groves, Old Irrigation, Old Surprises
Redlands’ citrus-grove past means many lots have unmapped irrigation lines and old grading that doesn’t show on any county record. When we excavate, we expect to find things buried. The right foundation approach on a former grove lot is often a standard slab with deeper footings at the perimeter, but we confirm soil conditions before we commit to a number. That’s how you avoid a change order halfway through the dig.
Trusted Brands We Service in Redlands
Sutton ADU Builders has hands-on experience with Abodu, Cover, and Dvele product lines, which gives Redlands homeowners a straight read on which prefab or modular system fits their lot, budget, and timeline. We know which models clear Redlands’ design-review standards and which ones need modification before they’ll pass plan check. If you’re considering a Tuff Shed conversion or a James Hardie exterior system, we can quote it accurately. Because we coordinate scheduling from our Inland Empire office, Redlands customers get faster turnaround on parts and site visits than they would from a builder based in Los Angeles or Orange County.
Common ADU Builders Problems We See in Redlands Homes
- Floodplain review surprises. Redlands lots in the San Timoteo Creek corridor can add four to eight weeks to the permit cycle because elevation certificates and drainage studies are required before plan check clears. Builders who quote you a fast timeline without checking your FEMA zone are guessing.
- Unpermitted legacy structures. Many Redlands lots still carry old citrus-era sheds, detached garages, or slab additions that were never permitted. The city may require demolition, legalization, or lot-coverage accounting before your ADU permit moves forward.
- Excavation surprises from old grove infrastructure. Buried irrigation lines, filled tree rows, and irregular grading from Redlands’ agricultural past can add $8,000 to $20,000 in sitework that a flat-lot quote never anticipated.
- Historic District design pushback. In the neighborhoods near Olive Avenue and Cajon Street, an ADU that looks like a generic box will stall in design review. Matching period character and materials matters to the city, and it matters to your neighbors.
Pricing for ADU Builders in Redlands, CA
Here are the ranges we quote most often in Redlands. A junior ADU or garage conversion runs $120,000 to $190,000. A studio ADU under 500 square feet lands between $160,000 and $240,000. A one-bedroom detached unit runs $190,000 to $280,000, and a two-bedroom unit with site work typically comes in at $260,000 to $360,000. Site work is the big swing factor: floodplain elevation requirements, unpermitted structure removal, utility trenching, and citrus-era grading corrections can add $12,000 to $35,000 to the base build. We deliver a written price before any work begins, so those numbers are yours to approve first. Call (472) 248-8213 for a free estimate with real numbers, not a vague range.
We Also Serve Cities Near Redlands
Sutton ADU Builders serves Redlands and the surrounding communities, including Loma Linda, Mentone, Colton, and Highland. If you’re outside Redlands proper but still in the Inland Empire, you’re getting the same Threshold Standard crew and the same written price. Learn more about our ADU Builders services or explore how we serve Redlands specifically.
Serving Redlands, CA - Our Local Coverage Area
We’re based in the Redlands 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 Builders in Redlands
Yes, in many cases. Redlands requires floodplain development review for any structure in designated FEMA flood zones, and those zones include portions of the San Timoteo Creek and Santa Ana River corridors that have not flooded in living memory. The trigger is your FEMA zone and the finished floor elevation, not whether you’ve personally seen water. Call (472) 248-8213 and we’ll check your parcel before you spend money on design work.
Plan check in Redlands typically takes four to eight months for a detached ADU, and longer if floodplain review or historic-district design review is triggered. Loma Linda and Highland can move faster on flat, non-floodplain lots, but Redlands’ specific review layers are the tradeoff for its historic protections and stormwater standards. Budget for it, and let our team manage the submittals.
Usually yes, but the unpermitted structure has to be reconciled first. Redlands may require demolition, legalization through a separate permit, or counting the structure toward lot coverage before your ADU plan check clears. We have handled this exact scenario on lots near the Historic District, including one where a prior non-permitted shed slab had to be demolished and verified by the city before the new foundation could be poured. Call us for an honest assessment, not a guess.
For most Redlands lots with former grove history, a standard slab-on-grade with deepened perimeter footings works well, but soil testing should confirm it. Lots near San Timoteo Creek or with old filled irrigation rows may need raised foundations or additional compaction. We confirm conditions before we price the foundation, so you’re not paying for surprises later. Call (472) 248-8213 for a free site walk.
Yes. ADUs in the Redlands Historic District must pass design review by the city’s preservation staff, which means your unit’s roofline, siding, window proportions, and setbacks have to be compatible with the surrounding period homes. We’ve matched James Hardie siding and period trim on units behind 1920s bungalows near Cajon Street and Olive Avenue and cleared review without major revisions. The work just has to be scoped correctly from day one.
Written by Miles Hartwell, Owner at Sutton ADU Builders, serving Redlands homeowners with written pricing and the 365-Day Done Right Promise.



