The Ellery ADU Studio Corona Guarantee
We stand behind every ADU we design, permit, and build in Corona with something most contractors treat as optional: a written promise signed before the first shovel hits dirt. Since 2015, we’ve completed 900+ ADUs across Southern California, and every single one started with a fixed written price and ended with a documented photo record of what was built. For Corona homeowners, that means no surprise invoices, no disappearing crews, and no arguments about whether the finished unit matches the permitted drawings. If it doesn’t, we make it right. That’s not a slogan - it’s Haven Standard Clause 7, and it goes in your contract.
What’s Covered
- Workmanship that matches the permitted drawings. Our 365-Day Done Right Promise means if the finished ADU deviates from the approved plans - wall placement off, window spec wrong, roofline not as drawn - we correct it at our expense, not yours. This applies to every ADU type we build in Corona: garage conversions, new detached units, Junior ADUs, and interior conversions.
- Parts and materials as specified. We don’t substitute mid-project without your written approval and a change order with a new price. Under Haven Standard Clause 5 (No Surprises), the scope is locked at signing; no door-side upsells, no scope creep. If we specified Abodu siding or James Hardie panels in your quote, that’s what gets installed.
- Site condition documentation. Every visit produces a dated photo record showing what we found and what we did. You receive the images, not a summary of how it felt. In Corona’s older neighborhoods like Corona Hills or the original downtown grid, this matters - we’ve documented everything from deteriorating garage slabs to utility lines that previous surveys missed.
- On-time milestone arrival. We commit to inspection-ready phases on schedule. If our crew misses a rough-in inspection window because we weren’t prepared, we absorb the re-inspection fees and the delay. Corona’s Building Department at 505 S. Buena Vista Ave. doesn’t reschedule fast; we don’t waste your slot.
- Honest pricing with zero invoice drift. Haven Standard Clause 1 requires a written price before any work starts. Every line item - design, permitting, site prep, utilities, finish - is fixed unless you request a change. We’ve turned away homeowners who wanted a verbal “ballpark” because that number always becomes a problem later.
- Prefab and modular system accountability. When we specify Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab, Tuff Shed, or James Hardie systems, we coordinate delivery, crane access, and integration with site utilities under our single contract. If the module doesn’t fit the pad we prepared, that’s our fix, not a finger-pointing exercise between designer and builder.
Our Satisfaction Promise
If something’s not right, here’s what happens: you call (951) 476-3715 and a live person answers - no voicemail queue, no callback promise that evaporates. We schedule a site visit within 48 hours, usually faster for Corona addresses inside the 91/15 corridor. Our project manager walks the unit with you against the permitted drawings and the photo record. If we missed something, we write a correction scope with a completion date and a fixed price of zero. The 365-Day Done Right Promise covers anything we built or installed that doesn’t match the contract documents. After 900+ ADUs, we’ve learned that most problems aren’t mysterious - they’re communication failures. Our fix is systematic: document what was promised, photograph what was delivered, close the gap in writing. We don’t offer “satisfaction” as a feeling; we offer specific corrections to specific deviations. If you’re comparing us to another Corona ADU contractor, bring us their written estimate - we’ll give you a Free Second Opinion on whether the scope and pricing hold up.
Before
AfterLicensed & Insured Backing
A guarantee is only as solid as the business behind it. Ellery ADU Studio Corona is licensed and insured, with background-checked, uniformed technicians and crews whose license numbers appear on every page of our site - verified, not just claimed. For Corona homeowners, this matters because ADU work triggers city permits, state HCD oversight for certain prefab systems, and utility interconnection agreements with Southern California Edison. An unlicensed operator can pull a permit that gets red-tagged mid-project, leaving you with a half-built structure and no recourse. Our insurance covers the property during construction, our workers, and the structural integrity of what we build. The license means we’ve passed California’s contractor examination and maintain bonding requirements. The insurance means if a crane drops a Mighty Buildings module on your neighbor’s fence, it’s covered. The Haven Standard means if we build your garage conversion ADU in Corona’s Sierra Del Oro neighborhood and the slab cracks because we missed the expansive soil note in the soils report, we fix the slab and the finish work it damaged. Nadia Ellery has operated this studio since 2015 with one rule: every promise in writing, every visit documented, every problem owned until it’s resolved.
What We Ask From You
Our guarantee works both ways. We ask Corona homeowners to review the written scope before signing, ask questions about any line item, and communicate concerns during construction - not six months after final inspection when a small fix has become a renovation. We ask that you protect the photo record we provide; it’s your evidence if a future buyer’s inspector questions the work. And we ask that you hold us to the same standard we hold ourselves: if we say Tuesday for rough electrical, we’re there Tuesday. If we’re not, call (951) 476-3715 and Nadia Ellery will know why before the conversation ends.
How the Haven Standard Protects Your Investment
ADUs in Corona are not small projects. A garage conversion ADU typically runs $85,000-$140,000 all-in, drawings through final inspection. A new detached ADU starts around $150,000 and climbs with size, finishes, and utility complexity. At those numbers, “trust me” is not a business model. The Haven Standard was built from the problems we saw other contractors create: verbal quotes that ballooned, scopes that shifted blame to the designer, photo records that didn’t exist. Clause 1 (written price), Clause 5 (no surprises), and Clause 7 (Done Right Promise) are the structural beams of our guarantee. They’re in your contract, not our marketing.
Ready to Talk?
Call (951) 476-3715 to schedule your free estimate. We’ll walk your Corona property, identify the ADU type that fits your lot and budget, and return a written line-item quote with no expiration pressure. If you already have a contractor’s estimate in hand, we’ll give you a Free Second Opinion - no obligation, no sales pitch, just a factual read on whether the scope covers what Corona’s Building Department will actually require.
Written by Nadia Ellery, Owner at Ellery ADU Studio Corona, serving Corona since 2015.