Fast, Reliable Home Addition Contractor Across Montclair
A home addition in Montclair typically runs $180 – $420 per square foot depending on finish level, with detached ADU conversions from garages starting around $140,000 and full second-story additions running $250,000 – $450,000. We’re Lodgewick ADU Builders, the ADU company of the Kingswell family, and we’ve worked on enough Montclair ranch homes to know exactly what these projects take. Our crews serve Montclair directly from the Inland Empire office, and every project gets a written price before a single nail is driven. Call (254) 602-5618 to set up a free estimate on your addition.
Key Takeaways:
- Typical addition costs in Montclair: $180 – $420 per square foot; garage-conversion ADUs from $140,000.
- Most Montclair homes have 100-amp electrical service, meaning a panel upgrade is almost always part of the job.
- Garage conversions within a half-mile of the Montclair Transcenter don’t need replacement parking under state law.
- Every project ships with The Kingswell Guarantee: written price, written timeline, written workmanship warranty.
Why Lodgewick ADU Builders Is Montclair’s Preferred Home Addition Contractor Company
Montclair homeowners call us because they’ve usually been through a bad build before. A price that moved after the job started, a crew that ghosted for three weeks, a punch list that never got punched. We run every Montclair project under The Kingswell Guarantee, and that word matters. Written price first. Real arrival window. Clean job site at the end of every day. Written guarantee delivered before work starts, with a free return visit if anything fails within 365 days. Russ Delmar leads our team, and he’s the one who walks your project plan with you before paperwork gets signed.
We know Montclair’s building stock like the back of our hand. The 1950s and 1960s ranch homes off Mission Boulevard, the detached block-wall garages behind Holt Avenue, the original 100-amp panels that were fine for a 1962 refrigerator and nothing else. That local knowledge means our quotes are realistic the first time, not after change orders start stacking up. Our Home Addition Contractor team works with live-answer scheduling, so when you call about your build, you get a person, not a voicemail tree.
Room Addition Contractor in Montclair
Room Addition Contractor work in Montclair almost always starts with an honest conversation about what the existing house can carry. These mid-century ranch homes sit on 6,000 – 8,000 square foot lots, which is enough room for a ground-level addition in most cases, but foundation type and roofline tie-in drive the budget. A stick-built room addition in Montclair runs $180 – $280 per square foot for a standard finish. Add architectural glass, custom millwork, or a specialty ceiling and you’re at $300 – $420 a square foot pretty fast.
Design-Build With Real Numbers
We don’t hand you a vague estimate and then “refine” it after demo starts. When we quote a room addition in Montclair, the price is written and fixed before ordering begins. If you want white-oak built-ins, a wall of glass facing the San Gabriels, or a custom ceiling detail, we price those line items specifically. You’ll see every dollar in writing before we commit to it.
Permits, Setbacks, and Montclair Codes
Montclair reviews addition plans through its building division like every other San Bernardino County city, and setbacks on these older lots can tighten what’s buildable. We pull permits, build to plan, and pass inspections. If the inspector flags something, we fix it under our guarantee. You don’t chase the city; we do.
Second Story Addition Contractor in Montclair
Second Story Addition Contractor work in Montclair is a different animal from a ground-level bump-out. You’re asking a 1960s single-story ranch to hold a whole new floor, which means an engineer looks at the existing slab or raised foundation, the framing, and the sheer wall requirements before we price anything. Expect $250 – $400 per square foot for a second-story addition in Montclair, with the lower end for simple bedrooms and baths and the upper end for primary suites with custom finishes.
Engineering Is the First Stop
On a recent second-story job in Montclair, the original foundation needed supplemental footings plus shear wall upgrades before we could frame upward. That’s not a surprise cost if you plan for it. We bring the structural engineer in during the quote phase, so the written price reflects the real work, not a guessing game.
Living Through a Second-Story Build
A second-story addition in Montclair usually means the family stays in the house while we work overhead. We sequence that carefully: demo and framing first, then roof cut-in and weatherproofing, then interior finish. The job site is broom-cleaned daily, and the crew shows up inside the arrival window we gave you. The Kingswell Way is not a slogan; it’s how these projects stay livable.
Trusted Brands We Service in Montclair
We build with materials we’d put in our own homes, and for Montclair clients that often means James Hardie siding for heat and sun durability, Abodu and Dvele prefab shells when the client wants speed and precision on a garage conversion, and Cover for custom panelized builds. Our crew is hands-on familiar with all of them, which means we’re not learning the product on your dime. When a Montclair job calls for a particular prefab module or a James Hardie finish, we coordinate the order directly so the lead time is real, not hopeful.
Common Home Addition Contractor Problems We See in Montclair Homes
- Quoting the addition before factoring the 100-amp panel. Nearly every original-service Montclair home we touch needs an electrical upgrade before an ADU or addition can be energized. If the quote doesn’t include it, the quote is wrong.
- Uninsulated garage shells that bake in summer. Montclair regularly hits 100°F+ from June through September. A stucco or block garage without spray-foam or rigid insulation becomes a sweatbox, not a bedroom. HVAC design and insulation are not optional line items here; they’re the project.
- Paying for replacement parking the state already exempts. Within half a mile of the Montclair Transcenter, California waives the ADU parking replacement requirement. We see quotes that add $15,000 – $25,000 for parking nobody needs to build. That’s money back in your budget.
- Ordering long-lead materials late. A custom kitchen, architectural glass, or a prefab Dvele shell can carry 12 – 16 week lead times. If the order drops after framing starts, crews sit idle and the calendar blows out. We lock material orders in writing during the quote phase, before anything gets cut.
Pricing for Home Addition Contractor in Montclair, CA
Here are real Montclair numbers, not ranges you have to call to unlock. Stick-built room additions run $180 – $280 per square foot. Second-story additions run $250 – $400 per square foot. Garage-conversion ADUs start around $140,000 and generally finish between $160,000 – $220,000 depending on finish level and the electrical upgrade scope. High-end work with custom millwork, architectural glass, and designer coordination runs $300 – $420 a square foot across most project types. The two line items that move a Montclair quote the most are the 100-amp panel upgrade (typically $3,500 – $6,000) and the insulation/HVAC system for converted garages (typically $8,000 – $15,000). Every price we give you is written and fixed before work starts. Call (254) 602-5618 to get your exact number.
Because California law waives ADU replacement-parking requirements within a half-mile of public transit, most of the blocks around Montclair’s Metrolink Transcenter can convert a detached two-car garage into a rentable unit without replacing lost parking, a math advantage car-dependent Chino and inland Ontario simply can’t match. That waiver chips $15,000 – $25,000 off the cost of a garage conversion here, and it’s the single biggest reason Montclair garage-conversion ADUs pencil out better than almost anywhere else in this part of the Inland Empire.
On a 1950s ranch off Monte Vista Avenue near the Transcenter, we converted a detached two-car garage into a one-bedroom ADU for a homeowner headed to LA-bound Metrolink, and the schedule, not labor, set the date: a Dvele prefab shell and a custom white-oak kitchen we built to the homeowner’s millwork drawings needed over 16 weeks of lead time, which we locked in writing before ordering. We also had to upgrade the original 100-amp service and spray-foam the uninsulated stucco shell to survive Inland Empire summers, and the unit rented to a commuter the same week we finished. That’s the Montclair playbook: lock the long-lead items first, build second, and let the Transcenter do the marketing for your rental.
We Also Serve Cities Near Montclair
Our crews work throughout the Pomona Valley and into the foothills. You’ll find us on jobs in Home Addition Contractor in Montclair proper, plus Claremont, Ontario, Pomona, La Verne, and the surrounding streets in between. If you’re close enough to see the San Gabriels from your front yard, chances are we’ve built nearby.
Serving Montclair, CA - Our Local Coverage Area
We’re based in the Montclair 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 Home Addition Contractor in Montclair
If your garage sits within a half-mile of the Montclair Transcenter, no. California state law waives the replacement parking requirement for ADUs within a half-mile of public transit, which covers a big slice of central Montclair. We’ll verify your parcel’s eligibility during the quote phase so you don’t spend $15,000 – $25,000 on parking nobody requires. Call (254) 602-5618 for a free estimate.
Because the original panels on most 1950s and 1960s Montclair ranch homes are 100-amp units designed for a much lighter electrical load. Add a mini-split, a kitchen, lighting, and appliance circuits to an ADU and you’ll exceed that capacity. A panel upgrade is usually $3,500 – $6,000, and a real quote includes it from the start. Call us for exact numbers on your panel.
Long-lead materials. Custom cabinetry, architectural glass, and prefab shells from companies like Dvele can carry 12 – 16 week lead times. If those orders go in late, the whole calendar slides. We lock material orders in writing during the quote phase, before any construction starts, so labor never sits idle waiting on a delivery. That’s how a high-end Montclair build stays on schedule.
Yes, and skipping it is the most common regret we see. Montclair’s Inland Empire summers sustain 100°F+ days for weeks, and an uninsulated block or stucco garage becomes dangerously hot without spray-foam or rigid insulation plus a properly sized mini-split. Expect to budget $8,000 – $15,000 for insulation and HVAC on a garage conversion here. We’ll show you exactly what’s needed in the written quote.
Yes. Room additions, second-story additions, bump-outs, and fully custom ADUs are all in our scope. If you want architectural glass, custom millwork, and a designer’s touch, we build to that level. The process starts with a written, fixed price, so you know what a custom Montclair build costs before you commit to anything.
Get Your Free Montclair Addition Estimate
We’re not asking you to sign a contract today. We’re asking you to price the project with someone who will put the number in writing and stand behind it. Call (254) 602-5618 and we’ll schedule a free estimate for your Montclair home addition, walk the property with you, and hand you a written scope and price. That’s The Kingswell Guarantee, and it applies to every project we build in Montclair.
Written by Russ Delmar, Owner at Lodgewick ADU Builders, serving Montclair since 2010.