Frequently Asked Questions

From signed contract to certificate of occupancy, most Chino Hills ADUs take 12 to 18 months. Design and permitting run 4 to 6 months, construction 8 to 12 months. Chino Hills Building & Safety reviews ADU plans in about 8 to 12 weeks currently, faster than some neighboring cities but slower than pre-2020 norms. We manage the full timeline in one contract, so there's no gap between designer and builder to blame.

We operate as a design-build studio, meaning the drawings, permit set, and construction come from one team with one price. We start with a site visit and feasibility study, then move to schematic design, permit documents, and build. The alternative, hiring an architect and contractor separately, is where most ADU projects fail, because each party can point at the other when costs balloon or timelines slip. Our contract covers all three phases.

Yes. We pull all permits and coordinate every inspection with Chino Hills Building & Safety. Our permit sets are produced in-house and tailored to the city's specific checklist, which we've refined through years of submissions. You receive copies of every approved document and inspection sign-off. Haven Standard Clause 4 requires evidence on every job, and that includes the full permit trail.

Yes, and many Chino Hills lots have meaningful grade change. We design for it from the first site visit, not as an afterthought. Retaining walls, stepped foundations, and split-level designs are standard tools for us. The cost difference between a flat build and a sloped build can be significant, which is why we photograph and measure grade before quoting. We've built on hillside lots from Sleepy Hollow to the northern canyon edges.

An ADU (accessory dwelling unit) is a standalone or attached secondary unit with its own kitchen and bathroom. A JADU (junior accessory dwelling unit) is created within the walls of an existing home, up to 500 square feet, sharing bathroom facilities and sometimes kitchen space. Chino Hills allows both, but JADUs have stricter owner-occupancy requirements. Most of our Chino Hills clients choose detached ADUs for rental income or family use.

We specify James Hardie fiber-cement siding on most Chino Hills ADUs because it meets Cal Fire wildfire-urban interface requirements and holds up to our hot, dry summers better than wood or vinyl. The product carries a 30-year warranty and comes in finishes that match existing homes in neighborhoods like Vellano and Oak Tree Downs. We discuss material options during schematic design and document your selection in the written scope.

We have experience with several prefab systems and can advise whether site-built or prefab makes sense for your Chino Hills property. Abodu units work well on flat lots with good access. Cover and Dvele offer more design flexibility but longer lead times. The key question is whether a prefab unit can meet Chino Hills' specific fire zone and setback requirements, which we assess during feasibility. Our design-build contract covers either path.

We specify Title 24-compliant windows and insulation for every Chino Hills ADU, typically dual-pane vinyl or fiberglass frames with low-E coating. Attic insulation hits R-38 minimum, walls R-21. These aren't upgrades, they're code requirements we build into the base price. Your written quote lists every material specification by brand and performance rating, so you can verify before we start.

Every pro working under our name is required to hold the license and insurance California requires for residential construction. Nadia Ellery leads the local branch, and we maintain general liability, workers compensation, and auto coverage. License numbers appear on every contract and permit application. We don't treat licensing as a selling point, it's the minimum standard for entry.

Our project managers and lead carpenters are Ellery employees. Specialized trades, electrical, plumbing, and HVAC are performed by licensed subcontractors we've vetted and worked with repeatedly. Haven Standard Clause 3 requires verified crews, meaning we confirm current license, insurance, and background check status for every person on your job. You receive documentation of who's on site and when.

We stop, document, and resolve. Haven Standard Clause 4 requires evidence on every job, photos and readings of what we found, so disputes don't devolve into memory contests. If a defect emerges after completion, our workmanship warranty covers it. The key is everything in writing from day one, which is why Clause 1 exists.

Contact your project manager directly. Our office hours are Monday through Friday 7:00 AM to 7:00 PM, and Sunday 7:00 AM to 7:00 PM. Saturday we're closed. For true emergencies, water line breaks, electrical hazards, your project manager has a direct line. We don't promise 24/7 response, we promise clear communication during real hours from a real person who knows your job.

Yes, we've taken over stalled ADU projects in Chino Hills, Chino, and Diamond Bar. The first step is a forensic site visit, we document what's been done, what's wrong, and what's needed to get permits reactivated. These rescues cost more than clean starts because of the uncertainty, but we quote them in writing like everything else. Bring your existing plans and permit history to the consultation.

Design phase typically starts within 2 to 3 weeks of signed contract. Construction start depends on permit approval, which in Chino Hills currently runs 8 to 12 weeks for ADUs. We don't play urgency theater, fake limited slots, or pressure you to sign. The timeline is what it is, and we communicate it honestly. What we do guarantee is that once we start, we arrive on schedule, Haven Standard Clause 2, with a real window, a named lead, and a text when we're on the way.

Our workmanship warranty covers defects in labor and installation for one year from certificate of occupancy. Manufacturer warranties, James Hardie siding, window systems, roofing, pass through at their stated terms, typically 10 to 30 years. Everything is documented in your closeout packet, including warranty registration instructions and our direct contact for claims. Haven Standard Clause 1 requires the warranty in writing before work starts, so there's no ambiguity about what's covered.

No. Haven Standard Clause 5 is explicit, no surprises, no scope creep, no "while we're in here" upsells. The only way the price changes is if you request a change in writing, which we then quote and you approve. We've honored this since 2015 because it's the single most important promise we make. Your final invoice matches your signed contract unless you changed the scope.

A complete closeout packet: final permit and inspection records, as-built drawings showing what we actually built, manufacturer warranties with registration confirmation, photos of concealed conditions, mechanical systems layout, and our workmanship warranty terms. Haven Standard Clause 4 requires evidence on every job, and you keep that evidence. When you sell the house or need a repair in year eight, you'll know exactly what's behind the walls.

Because we built it, and we documented it. The same team that drew the plans executes the build, so there's no handoff gap where details get lost. We photograph critical junctions, foundation dimensions, framing layout, and MEP rough-ins. Final inspection confirms code compliance, and your as-builts confirm it matches the design intent. That's the design-build advantage in one sentence.

Written by Nadia Ellery, Owner at Ellery ADU Studio Chino Hills, serving Chino Hills, Chino, Yorba Linda, Anaheim, Diamond Bar, Pomona, Eastvale, Montclair, Ontario, Rowland Heights, Corona, and Upland since 2015.