A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Aliso Viejo, CA
An ADU in Aliso Viejo usually costs between $140,000 and $350,000 depending on whether you convert the garage or build a detached unit in the yard. What makes Aliso Viejo different from most Orange County cities is the dual layer of oversight: city plan check plus AVCA design review on nearly every lot. We price the work in writing before anything starts, and we build to The Garrison Standard. Call (424) 577-4306 for a free estimate.
Why Aliso Viejo Homes Are Different
Aliso Viejo is one of California’s largest master-planned communities. Most of the housing stock went up in the 1990s and early 2000s: Mediterranean-style tract homes with stucco exteriors, tile roofs, and modest lots. Many of those lots have a zero-lot-line setback on one side, which means the house sits tight against the property edge and the usable side yard is on only one side of the home. That single condition shapes more ADU decisions here than almost anything else.
The Aliso Viejo Community Association (AVCA) governs architectural standards across the city’s neighborhoods. A detached ADU in the side yard often needs a setback variance, which is the city’s written permission to build closer to the property line than the standard rule allows. AVCA has its own design review on top of that. In practice, homeowners in Aliso Viejo lean toward garage conversions or compact detached units tucked into the rear yard rather than attached additions that run along the narrow side. Mild coastal weather keeps heating and cooling loads moderate, but Santa Ana season makes fire-resistant siding and proper eave venting a real requirement, not a line item to skip.
Our Main Aliso Viejo Services
Most calls we take in Aliso Viejo start with one of three jobs: adding a room, converting a garage into living space, or building a detached ADU. Here’s how each one typically works in this city.
Room Addition Contractor in Aliso Viejo
Room additions in Aliso Viejo almost always mean working within a tight side or rear setback, and on many zero-lot-line lots the only practical direction to build is back. That changes roof tie-in details and drainage routing, and it’s why we survey the lot before we price anything. Stucco matching on a 1990s Mediterranean exterior takes a patient hand, and we use James Hardie siding where the design calls for a clean break between old and new. Room Addition Contractor in Aliso Viejo
Garage Conversion Contractor in Aliso Viejo
Garage conversions are the most common ADU route in Aliso Viejo because the structure already exists, which typically keeps the budget between $90,000 and $150,000. The challenge here is that many attached townhome garages sit close to a neighbor’s wall, so sound separation and fire-rated assemblies come up on nearly every job. AVCA design review also cares about curb appearance when the garage door comes out and a wall goes in. We handle the permit path and the HOA submittal together. Garage Conversion Contractor in Aliso Viejo
ADU Builders in Aliso Viejo
Detached ADUs in Aliso Viejo tend to be compact rear-yard units, often 400 to 800 square feet, positioned to respect both city setbacks and AVCA’s architectural standards. We build conventional framed units and we also work directly with prefab platforms like Dvele, Mighty Buildings, and Boxabl, which can shorten on-site time on lots where access is tight. Every ADU gets a written price before work starts and a full year of written guarantee when the job is done. ADU Builders in Aliso Viejo
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Aliso Viejo
We work with Dvele, Mighty Buildings, and Boxabl on Aliso Viejo ADUs, and we build conventional units with James Hardie siding. Parts lead times depend on the platform, but our prefab partners keep the process moving without us guessing on delivery. Learn more on our brands page.
Pricing for ADU Company in Aliso Viejo, CA
| Service | Typical range in Aliso Viejo |
|---|---|
| Garage conversion ADU | $90,000 – $150,000 |
| Detached backyard ADU (compact) | $140,000 – $250,000 |
| Detached backyard ADU (full size) | $200,000 – $350,000 |
| Room addition (single room) | $60,000 – $110,000 |
| Room addition (primary suite) | $90,000 – $160,000 |
| Second-story addition | $150,000 – $300,000 |
Aliso Viejo prices push toward the upper end of these ranges when the lot has a zero-lot-line condition that forces a variance, or when AVCA requires design revisions before approval. When we hand you a written price, that number does not move. It is the same on the final invoice as it was on day one.
Neighborhoods We Serve in Aliso Viejo
We work across the city’s residential villages, most of which are organized around AVCA-managed parks and school clusters. Lot geometry and HOA sub-association rules vary from one village to the next, so we always check both the city and association guidelines before the first site visit.
- Glenwood
- Westridge
- Pacific Ridge
- Vista Pointe
- Laguna Audubon
We schedule estimates throughout Aliso Viejo on a rolling basis and can usually be on site within a few days of a call.
Service Area – Cities Near Aliso Viejo
Fielding ADU Orange County serves Aliso Viejo and the surrounding south county cities. Homeowners in Laguna Woods, CA, Ladera Ranch, CA, Rancho Santa Margarita, CA, and Newport Beach, CA can reach our local crews through the same office and the same phone number.
Serving Aliso Viejo, CA - Our Local Coverage Area
We’re based in the Aliso Viejo 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 ADU Company in Aliso Viejo
We typically schedule estimates within a few days of your call. The estimate includes a full lot review, a look at the setbacks and AVCA design constraints on your specific lot, and a written price you can hold us to before any work starts.
Yes, on most lots you need both. The city handles building permits and zoning, while AVCA applies its own architectural design standards. We prepare both submittals as part of the job, so you are not running between two offices trying to figure out who wants what.
No. The price we write down before work starts is the price you pay at the end. That is how The Garrison Code works here. If something changes in the field that affects scope, we talk to you first and put any revision in writing before proceeding. Call (424) 577-4306 for a free estimate.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Aliso Viejo Customers Say
"Insulation, drywall, and finishes were all well done. Feels like part of the house."
- Pete O."Good addition. Electrical inspection delayed a week, which was the county, but the build is great."
- Eva K."Room addition over the back patio. Framing is square, windows are tight, and the roofline matches."
- Danny L.
