Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Irvine
A typical home addition in Irvine runs $45,000-$130,000, while a full detached ADU construction runs $90,000-$220,000, with most projects clearing both City of Irvine permits and village HOA Architectural Review in 8-14 weeks. Our Home Additions & ADU team serves Irvine from our Los Angeles metro office, with crews dispatched daily to Woodbridge, Turtle Rock, Northwood, and the Great Park Neighborhoods. Call (657) 227-2502 to schedule your free written estimate - every quote includes a line-item scope, a fixed price, and a documented photo record of existing conditions before any work starts.
Why Rowan Construction Group Irvine Is Irvine’s Preferred Home Additions & ADU Company
We’ve delivered 4,000-plus projects since 2007, every one with a written price before work started and a documented record when the crew left. In Irvine specifically, that discipline matters more than in neighboring cities because the dual-approval structure - City of Irvine building and planning plus village-level HOA Architectural Review - creates more touchpoints where an undocumented promise becomes an expensive dispute.
Our crews are background-checked and uniformed; a live person answers calls 24/7. Every visit includes a documented photo record as standard, not an upgrade. Under the 365-Day Done Right Promise, if it is not done right, we make it right - backed by The Haven Standard, not a handshake. And under Clause 1 of that same standard, the price is written before anyone picks up a tool, every time.
We offer a Free Second Opinion on any written estimate - bring a competitor’s quote and we’ll review it line by line at no charge. No change proceeds without a signed change order, which is the administrative discipline Haven acquired Rowan for, and the reason our projects finish within a few percent of the number the customer agreed to.
Our Home Additions & ADU Services in Irvine
ADU Design & Permitting in Irvine
ADU design and permitting in Irvine is not a single-track process. The City of Irvine’s building department reviews structural, electrical, plumbing, and energy code compliance, while the village HOA Architectural Review Committee - Woodbridge, Turtle Rock, Northwood, each with distinct CC&Rs - governs massing, setbacks, exterior materials, and roofline compatibility. We prepare dual-submission packages from the start, so City approval and HOA approval run parallel rather than sequential. A typical garage conversion ADU in Irvine runs $30,000-$80,000; a new detached ADU runs $90,000-$220,000. Both prices include our time in the permit and HOA review cycle, because that time is predictable here.
Garage Conversion ADU in Irvine
Garage conversions are the most common ADU type we build in Irvine’s older villages, particularly in Woodbridge and University Park where 1970s-80s post-tension slab foundations underlie the original structure. The existing slab often becomes the ADU floor, but any new plumbing rough-in - a kitchen sink, a bathroom drain - requires cutting the slab. Before that cut, we pull original cable-layout drawings from the Irvine Company construction archive and scan to confirm no live tensioning cables in the path. This step does not exist in neighboring Orange County cities. Skip it, sever a cable, and the structural failure is catastrophic and uninsured.
New Detached ADU in Irvine
New detached ADUs in Irvine face the strictest design scrutiny of any project type. The HOA Architectural Review Committee in villages like Turtle Rock and Northwood enforces roof pitch, exterior cladding, and even window-grid patterns that match the existing neighborhood character. We design to those standards from the first draft, not after a rejection. Near Irvine’s coastal-influenced edges, we specify marine-grade fasteners and hardware - stainless or hot-dip galvanized, never cheap electro-galvanized - because salt air corrodes inland-spec materials within a few years. The coastal-spec adds cost upfront. The cheap spec adds replacement cost within a decade.
Junior ADU & Interior Conversion in Irvine
Junior ADUs, or JADUs, convert existing interior space - a bedroom wing, a bonus room - into a self-contained unit with a kitchenette and separate entrance. In Irvine’s newer 1990s-2000s wood-frame construction, these are straightforward structurally. In 1970s-80s post-tension slab villages, any new wet bar or bathroom drain still requires the same cable-layout review. We handle that verification before quoting, so the price we write is the price you pay.
Second Story Additions in Irvine
Second story additions in Irvine require structural analysis of the existing foundation - post-tension slabs in older villages were not designed for vertical loads above original spec. We engage a structural engineer early, pull original construction documents from the Irvine Company archive when available, and design the addition to the actual capacity of what’s in the ground, not what we assume. This engineering step adds 2-3 weeks and $3,500-$7,000 to the project, but it prevents the alternative: a second story that cracks the slab below.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Before
AfterTrusted Brands We Service in Irvine
We source across fifty-plus vetted brands, giving the written quote honest numbers rather than inflated ones. For Irvine’s coastal-influenced conditions, we specify GAF Timberline HDZ shingles with StainGuard protection on addition rooflines, Owens Corning Duration series where fire-resistant ratings apply, and Grohe fixtures with StarLight chrome finish that resists salt-air corrosion in outdoor kitchen and exterior hose-bib applications. We stock no inventory - every material is ordered to the specific job, with lead times disclosed in the written quote so there are no schedule surprises.
Common Home Additions & ADU Problems We See in Irvine Homes
- Post-tension slab penetration without cable maps. In Woodbridge and University Park, cutting a slab for a new drain line or HVAC chase without pulling original cable-layout drawings from the Irvine Company archive can sever a live tensioning cable. The structural failure is immediate, and contractor liability coverage is voided because the cut was made without due diligence available to any local crew.
- Inland-spec hardware on coastal-adjacent additions. Additions near Irvine’s western and southern edges - Shady Canyon, Quail Hill, parts of Turtle Rock - face salt-air exposure that corrodes electro-galvanized fasteners and aluminum window frames within 3-5 years. We specify marine-grade stainless or hot-dip galvanized hardware and anodized or clad window frames; the upfront cost difference is 8-15%, but the replacement cost avoided is the full installation labor plus material.
- City-approved plans rejected by village HOA. We regularly see projects where a homeowner or out-of-market contractor secured City of Irvine building permits, started work, and then faced a stop-work from the HOA Architectural Review Committee because roof pitch, setback, or exterior material did not match village CC&Rs. The redesign adds weeks and can fracture the draw schedule. We submit to both simultaneously from day one.
- Fall Santa Ana wind debris on open-framed structures. During Santa Ana events, typically September through November, Irvine’s inland-adjacent edges face elevated fire risk and high wind. Open-framed additions under construction require daily debris control and fire-resistant material staging; we build this into the site-prep phase, not as a weather-day afterthought.
Pricing for Home Additions & ADU in Irvine, CA
Every project is quoted with a flat written price and written scope before work begins. No change proceeds without a signed change order. Below are the ranges we see in the Irvine market, calibrated to the dual-approval timeline, coastal-spec material requirements, and post-tension slab protocols that distinguish this city from surrounding Orange County markets.
| Service | Price Range in Irvine |
|---|---|
| Home Addition | $45,000-$130,000 |
| ADU Construction | $90,000-$220,000 |
| Garage Conversion | $30,000-$80,000 |
What moves the number within these ranges: foundation type (post-tension slab protocols add engineering and scanning costs), HOA Architectural Review complexity (village-specific design requirements), coastal-spec material upgrades, and utility tie-in distance from main to ADU. A room addition on a 1990s wood-frame home in Northwood with no HOA design variance typically lands at the lower end. A new detached ADU in Turtle Rock with full coastal-spec materials, post-tension slab utility chase, and two rounds of HOA design review typically lands at the higher end. Call (657) 227-2502 for an exact quote - estimates are free, and we deliver the written price before any work starts.
We Also Serve Cities Near Irvine
Our Home Additions & ADU in Irvine crews also work in Tustin, Santa Ana, Orange, and Lake Forest. Each city has its own permit timeline and HOA landscape; we adjust our submission protocols accordingly, but the Haven Standard - written price first, signed change orders, documented photo records - applies everywhere we work.
Serving Irvine, CA - Our Local Coverage Area
We’re based in the Irvine 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 - Home Additions & ADU in Irvine
An ADU in Irvine typically costs 10-20% more than in neighboring Tustin or Santa Ana because of the dual-approval requirement: City of Irvine building and planning permits plus village HOA Architectural Review, plus the post-tension slab protocols and coastal-spec material upgrades that are standard here and optional elsewhere. The extra cost buys documentation - cable-layout scans, marine-grade hardware, dual-submission plans - that prevents far more expensive failures. Call (657) 227-2502 for a line-item quote that shows exactly where the difference lies.
Yes, we build ADUs on post-tension slabs in Woodbridge and University Park regularly, but only after pulling original cable-layout drawings from the Irvine Company construction archive and scanning to confirm no live tensioning cables in the cut path. This step is non-negotiable and specific to Irvine’s 1970s-80s villages. In Woodbridge, our crew tied a new detached ADU’s utility rough-in into a 1978 post-tension slab. We pulled the original drawings, scanned the slab, laid out the chase on the confirmed path, passed inspection, and closed the rough-in without incident. A crew from outside Irvine cutting blind would have severed a live cable and caused total structural failure. Call (657) 227-2502 to schedule a site review.
You need both, and we recommend submitting to both simultaneously rather than sequentially. The City of Irvine building department reviews code compliance; the village HOA Architectural Review Committee - Woodbridge, Turtle Rock, Northwood, each with distinct CC&Rs - reviews design compatibility. Getting City approval first and HOA rejection second adds weeks and can force a redesign after your draw schedule has started. Our submission packages address both sets of requirements from the first draft. Call (657) 227-2502 and we’ll review your village’s specific CC&Rs at no charge.
The upgrades that matter are stainless or hot-dip galvanized fasteners (never electro-galvanized), anodized or thermally broken aluminum window frames, and sealed paver joints with polymeric sand rather than loose jointing. These matter most within 3-5 miles of Irvine’s coastal-influenced western and southern edges, where salt air accelerates corrosion. The upfront cost increase is 8-15%; the avoided replacement cost is the full material plus labor to re-install. Inland-spec hardware on a coastal-adjacent addition is a false economy we see fail regularly. Call (657) 227-2502 and we’ll specify for your exact location.
The first step is pulling original cable-layout drawings from the Irvine Company construction archive, then scanning the slab to confirm no live tensioning cables in the proposed cut path. This step is specific to Irvine’s 1970s-80s post-tension slab villages and does not exist in neighboring Orange County cities. Skip it, sever a cable, and the structural failure is catastrophic and uninsured. We verify before we quote, so the price we write includes this step and the liability protection it provides. Call (657) 227-2502 to schedule your free estimate.
Ready to add space to your Irvine home? Call (657) 227-2502 to schedule your free written estimate. We’ll review your existing conditions, pull the relevant documentation for your village and foundation type, and deliver a fixed-price quote with a written scope before any work starts. Under the Haven Standard, no change proceeds without a signed change order, and every visit includes a documented photo record. Grant Rowan and our Irvine-area crews are standing by.
Written by Grant Rowan, Owner at Rowan Construction Group, serving Irvine since 2007.