Mighty Buildings Junior ADU & Interior Conversion in Upland: What to Know First
We provide independent Mighty Buildings junior ADU and interior conversion services in Upland, with most projects moving from signed contract to permitted construction start in 10 to 14 weeks. Every project carries a written price before any work begins, per Haven Standard Clause 1, and falls under our 365-Day Done Right Promise.
This page is for Upland homeowners who already own a Mighty Buildings unit or are considering one for a basement ADU, above-garage conversion, room-to-ADU conversion, attached addition, or interior JADU. You need a design-build studio that understands the panelized composite system Mighty Buildings uses, not a general contractor who treats it like stick framing. Call (840) 212-3065 to schedule your free estimate, or bring us a written estimate already in hand for a Free Second Opinion.
How Mighty Buildings Products Fail - and How We Fix Them
- Mighty Buildings M Series panel delamination at window openings. The fiber-reinforced polymer skin can separate from the insulating core at rough openings when the unit has been exposed to Upland’s thermal cycling - 95-degree summer days dropping to 45-degree winter nights. We map the delamination with thermal imaging, cut back to sound panel, and splice in new factory panels or field-fabricated composite patches that match the original R-value. The fix is documented in your photo record before we close the wall.
- Mighty Buildings Quattro series plumbing chase condensation in above-garage ADUs. The compact vertical chases in this line weren’t always detailed with a continuous vapor barrier at the ceiling penetration. In Upland, where garage roof cavities can hit 140 degrees, warm moist air hits the chase and condenses. We open the chase, install a proper vapor barrier with sealed penetrations, and add a small exhaust pathway if the mechanical layout allows. This isn’t a leak - it’s a detail omission we catch during our initial site survey.
- Mighty Buildings B2 series electrical panel overheating in interior JADU applications. The B2 ships with a compact load center that works fine in detached applications but can run warm when shoehorned into an existing interior wall with poor airflow. We calculate actual load against the panel’s derated capacity, then either relocate the panel to a ventilated soffit or upgrade to a higher-amp bus with proper clearances. We document the before-and-after temperatures in your photo record.
- Mighty Buildings unit-to-foundation settlement gap on sloped Upland lots. The San Antonio Heights area and streets north of Foothill Boulevard see more cut-and-fill grading than flatland Upland. Mighty Buildings’ steel frame skids can create a visible gap as the pad settles differentially. We don’t shim and hope - we lift, regrade with compacted base, and install adjustable pier supports that let future leveling happen without disturbing the unit. The pier specification goes into your permit set as an as-built detail.
- Mighty Buildings M Series HVAC integration failures in room-to-ADU conversions. The M Series mini-split rough-in location sometimes conflicts with existing joist bays when the unit is inserted into a framed interior space. Rather than notch structural members, we redesign the refrigerant line path using the manufacturer’s approved alternative routing, submit the change as a revised mechanical plan to San Bernardino County, and coordinate the final pressure test with the HVAC sub. The revised plan becomes part of your documented permit set.
Our Mighty Buildings Junior ADU & Interior Conversion Process
- 1
Site survey and Mighty Buildings serial verification. We record the unit series, manufacture date, and any prior modifications. Nadia Ellery or a senior tech walks the existing conditions with a checklist specific to your Mighty Buildings line.
- 2
Diagnostic imaging and load calculations. Thermal imaging for envelope issues, electrical load calcs for panel capacity, and structural assessment for settlement or bearing. You receive a documented photo record of everything we find.
- 3
Parts decision: OEM versus quality aftermarket. Mighty Buildings panels and proprietary connectors come from the factory with a 10-year structural warranty. We use OEM where the warranty requires it and source tested aftermarket equivalents for out-of-warranty components, with the tradeoff explained in writing.
- 4
Permit set revision and submission. As an independent Mighty Buildings service provider, we prepare the revised structural, mechanical, and electrical plans for San Bernardino County permit review. No gap between designer and builder - it’s one contract, one written price.
- 5
Construction, testing, and documentation. We build to the permitted drawings, pressure-test mechanical systems, verify electrical loads under operation, and photograph every critical stage. The final packet includes as-builts, test results, and your warranty documentation.
- 6
Final inspection and 365-Day Done Right activation. We walk the inspector through the work, address any corrections under our contract (not yours), and activate your written promise. If it’s not built to the permitted drawings, we make it right.
What Mighty Buildings Junior ADU & Interior Conversion Costs in Upland
| Project Type | Typical Range | What Moves the Price |
|---|---|---|
| Interior JADU (existing room, M or B2 series insert) | $85,000 - $140,000 | Electrical service upgrade, plumbing distance, permit complexity |
| Above-garage ADU (Quattro or M series) | $120,000 - $195,000 | Garage structural reinforcement, stair access, fire separation |
| Basement ADU (B2 series, conditioned below-grade) | $95,000 - $165,000 | Moisture remediation, egress window, ceiling height compliance |
| Attached addition ADU (M series extension) | $110,000 - $185,000 | Foundation tie-in, roofline integration, utility extension length |
| Panel delamination or structural repair (per incident) | $4,500 - $12,000 | Panel count, accessibility, whether OEM or aftermarket |
These ranges are all-in: drawings, permit fees, construction, and final inspection. Under Haven Standard Clause 1, the written price you receive before work starts is the price you pay. No change orders for scope we’ve already identified. Call (840) 212-3065 for your exact quote - estimates are free.
Why Upland Homeowners Call Ellery ADU Studio Upland for Mighty Buildings Work
We’ve specified and coordinated Mighty Buildings, Abodu, Cover, and Dvele systems since the first prefab ADU ordinances hit California. That multi-brand fluency matters when your Mighty Buildings unit needs a component that’s back-ordered or discontinued - we know which aftermarket solution meets the original specification without voiding what warranty remains.
Our crew is background-checked, uniformed, and licensed; the license number appears on every page of your contract. A live person answers calls 24/7. And the 365-Day Done Right Promise isn’t a handshake - it’s a clause you can read before you sign. Read the clause, then read the cost range - if either one surprises you, we haven’t done our job yet.
We’ve designed, permitted, and built 900-plus ADUs since 2015, every one with a written price first and a documented photo record at completion. Most recently, Nadia Ellery’s crew wrapped a detached studio on a corner lot near the Upland Lemon Avenue corridor, working through the same San Bernardino County permit cycle your project will face.
FAQs
No - as an independent Mighty Buildings service provider, we work within the warranty terms that apply to your unit’s age and series. We use OEM parts where the warranty requires them and document every decision in writing. For out-of-warranty work, we explain the aftermarket tradeoff before you commit. Call (840) 212-3065 for a free estimate.
OEM panels and proprietary connectors typically ship from the factory in 4 to 6 weeks. We stock common aftermarket alternatives for out-of-warranty repairs and coordinate factory lead times into your project schedule so construction doesn’t pause mid-stream. Call (840) 212-3065 to check current availability for your series.
Repair makes sense when the core structure is sound and the fix addresses a specific failure mode. We recommend replacement or a different system when the cumulative repair cost exceeds 40 percent of a new unit’s installed price, or when the original placement violates current Upland setback rules that a new build could solve. We give you both numbers in writing. Call (840) 212-3065 for an assessment.
Most projects move from signed contract to construction start in 10 to 14 weeks, with permit review by San Bernardino County taking the largest share of that time. We don’t promise same-day or same-week starts on planned construction - that’s not how design-build work happens. We do promise a written schedule with named milestones before you sign. Call (840) 212-3065 to review the timeline for your specific project.
No. Under Haven Standard Clause 5 (No Surprises), the scope is locked at signing. If we missed something during survey, that’s our cost to absorb, not yours. The only price movement comes from client-requested changes, which require a written change order with a new price before any additional work proceeds. Call (840) 212-3065 for your fixed written quote.
Written by Nadia Ellery, Principal, Ellery ADU Studio Upland at Ellery ADU Studio Upland, serving Upland and nearby areas.