ADU Specials in Diamond Bar, CA
We keep a few standing offers running because Diamond Bar homeowners deserve to know what they’re walking into before they spend a dime. Call (657) 239-4865 and we’ll tell you exactly which offers apply to your project. No games, no “limited time” pressure, just honest value on ADU work we’ve been doing here since 2015.
Current Offers
Free Second Opinion on Any Written Estimate
Already have a quote from another ADU builder or design firm? Bring it in. We’ll review the scope, the line items, and the permit strategy, then tell you where we see gaps or where the price makes sense. This isn’t a bait-and-switch; it’s a real second set of eyes from a team that’s permitted 900+ ADUs.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
Written Price Guarantee - No Exceptions
Every Ellery project ships with Haven Standard Clause 1: a written, line-item price before any work starts. No “call for a quote” runaround, no verbal estimates that shift at permit. If another firm won’t put their number in writing, we’ll show you what a proper scope looks like - free.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
365-Day Done Right Promise - In Writing, Up Front
Before your project starts, you’ll receive our written Done Right Promise: if the finished ADU isn’t built to the permitted drawings, we make it right. No chasing, no “that’s not our department.” This applies to every garage conversion, detached ADU, and JADU we build in Diamond Bar - not a special, just our standard, confirmed in your contract.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
Documented Photo Record on Every Visit - Included
Every Ellery crew documents what they find and what they do, with photos you receive directly. No summary of “how it felt” - evidence of what happened. This is standard on all five services: ADU Design & Permitting, Garage Conversion ADU, New Detached ADU, Junior ADU & Interior Conversion, and ADU Site Prep & Utilities.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
Live Person Answers 24/7 - No Voicemail Queue
Call (657) 239-4865 any time and a real person picks up. Not a callback promise that doesn’t materialize, not an AI chatbot. If you’re up late worrying about setback variances or whether your garage slab will pass inspection, we’re here to talk it through.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
One-Contract Design-Build - No Designer-Builder Finger-Pointing
Our ADU Design & Permitting, build, and utility coordination live under one contract at one written price. If something’s off, we fix it. No passing blame between the architect and the contractor. This saves Diamond Bar homeowners roughly 6-10 weeks of coordination time versus the typical two-contract model, and eliminates the “not my scope” conversations that derail projects.
Valid through December 31, 2026. Mention this offer when you call (657) 239-4865.
How to Redeem
Step 1: Call (657) 239-4865 and mention which offer caught your eye. A live person will walk through your project basics and schedule a site visit.
Step 2: We’ll book your visit, confirm the address in Diamond Bar or nearby, and send calendar confirmation with Nadia Ellery’s direct contact for any prep questions.
Step 3: Present your mention at the first site walk. Your written quote will reflect every applicable offer, locked under Haven Standard Clause 1 before any work begins.
What These Offers Actually Cover
We’re not in the business of “up to 50% off” math that never applies to real projects. The offers above are structural advantages we give every Diamond Bar client, not coupon-code tricks. Here’s what that means in practice:
- Garage Conversion ADU: Typical all-in range runs $85,000-$165,000 depending on existing slab condition, electrical service capacity, and whether the roof structure needs modification. Your written quote breaks out each line item - foundation, framing, MEP, finishes - so you see where the money goes.
- New Detached ADU: Generally $175,000-$350,000 for a 1-bedroom unit in Diamond Bar’s market, with variance for prefab systems (Abodu, Cover, Dvele, Mighty Buildings, Boxabl, Plant Prefab) versus stick-built. We specify and coordinate both under the same single contract.
- Junior ADU & Interior Conversion: Often $45,000-$95,000 when working within existing envelope, though Diamond Bar’s hillside lots and older HVAC systems can push the upper bound. We flag those realities in the first walk, not at permit submittal.
- ADU Site Prep & Utilities: Trenching, sewer lateral upsizing, electrical service upgrades, and gas line extensions run $8,000-$35,000 as standalone scope, though most clients bundle this into the full build contract for cleaner coordination.
Every price above is representative of what we’ve seen in Diamond Bar’s market since 2015. Your exact number comes after we walk the site, pull the assessor’s records, and confirm utility locations. The only promise we make before that visit: you’ll have a written, line-item price in hand before any work starts. That’s Haven Standard Clause 1, and it’s not negotiable.
Why We Don’t Do “Limited Time” Pressure
We’ve watched other ADU firms in Los Angeles County run countdown timers and “only 3 permit slots left” urgency. It works for selling mattresses, not for six-figure construction decisions. Diamond Bar’s planning department runs on its own calendar, not ours. What we can control is transparency: what you’ll pay, what you’ll get, and what happens if something’s not right.
The 365-Day Done Right Promise, the documented photo record, the live person on the phone - these aren’t loss-leaders to get you in the door. They’re how we’ve operated since Nadia Ellery founded this studio in 2015, and how we’ll keep operating after December 31, 2026 passes.
Common Questions About Our Offers
Can I combine multiple offers?
Every offer listed above is standard on every Ellery project - they’re not mutually exclusive discounts to stack. Your written quote will include the photo record, the Done Right Promise, and the single-contract structure automatically. Call (657) 239-4865 and we’ll confirm exactly what applies to your specific ADU type.
Do the prices change once work starts?
Under Haven Standard Clause 5 (No Surprises), the scope is locked at signing. No door-side upsells, no scope creep. If you change your mind about finishes or layout after permit approval, we’ll document the change order in writing with a new price - but we don’t “find” problems that mysteriously cost more. We’ve been doing this too long for that.
What if I already started with another designer?
Bring your permit set or partial drawings. We’ll review what’s been done, identify any gaps we’ve seen stall Diamond Bar projects, and quote the remaining work under our single contract. The Free Second Opinion applies even if you’re mid-process.
How do I know the crew is legitimate?
Every technician and crew member is background-checked and uniformed, and our license number appears on every page of this site. Verified, not just claimed. In Diamond Bar, where the Building & Safety Division knows most repeat players by name, that matters.
Written by Nadia Ellery, Owner at Ellery ADU Studio Diamond Bar, serving Diamond Bar since 2015.