Home Additions & ADU in Aliso Viejo - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Aliso Viejo

A room addition or ADU in Aliso Viejo typically runs between $45,000 and $130,000, with detached ADUs landing in the $90,000 to $220,000 range depending on site prep and finishes. Most projects here take four to seven months from first design meeting to final inspection, not because the building is slow, but because the HOA architectural review and city permit process in a master-planned community has more steps than most homeowners expect. That’s where we come in.

Call (877) 610-1318

Barrett & Sons Construction has been building in South Orange County long enough to know that Aliso Viejo is a different animal than Irvine or Lake Forest. The HOAs here review nearly every exterior change, the hillside lots demand real grading knowledge, and the entire housing stock was built in one narrow window that’s now aging all at once. We coordinate with your association board, pull every permit, and put every allowance and change order in writing before work starts. Call (877) 610-1318 to schedule a free estimate, and we’ll walk your property with you before you commit to anything.

Why Barrett & Sons Construction Is Aliso Viejo’s Preferred Home Additions & ADU Company

Tom Barrett founded this company in 1998, and he still answers his own phone. When you call about an addition in the Glenwood or Westridge neighborhoods, you’re talking to someone whose sons run the crews and whose name is on the contract. That matters in Aliso Viejo, where most homes are now 25 to 40 years old and the original construction is starting to show its age in predictable, tract-specific ways.

We’ve built additions and ADUs across the 92656 and 92698 ZIP codes, from single-story room additions near Aliso Viejo Middle School to detached units on hillside pads above Wood Canyon. Our customers tell us the same thing: the written change order process, the permits pulled on every eligible job, and the 90-Day Done Right Promise are why they signed. One call to (877) 610-1318 gets you a live person, not a voicemail box, and a straight answer about what your project will actually cost.

If you’ve been burned before by a national outfit that quoted one number and billed another, you’ll notice the difference immediately. Tom publishes his name, his address, and his license number. Every price change arrives in writing before a single nail moves. And the permit inspector works for you, not Tom. That’s the whole point.

Our Home Additions & ADU Services in Aliso Viejo

ADU Design & Permitting

California state law now allows accessory dwelling units on nearly every residential lot in Aliso Viejo, but state law doesn’t override your HOA’s architectural committee. Here’s what we’ve learned from dozens of local applications: the HOA step is the one that catches homeowners off guard, because many HOAs in Aliso Viejo have their own design standards for roof pitch, exterior color, window placement, even fence height. Our Home Additions & ADU team handles the full package: measured drawings, HOA submittal packet, city plan check, engineering, and permits. You won’t have to chase paperwork across three different counters.

Garage Conversion ADU

A garage conversion in Aliso Viejo runs $30,000 to $80,000, and it’s often the fastest path to a rentable unit because the foundation, framing, and roof already exist. In neighborhoods like Canyon View Estates, where many homes were built with three-car garages and wide driveways, a conversion can add 400 to 600 square feet of living space without touching your lot coverage limits. We handle the drywall, insulation, electrical, plumbing, and the critical permitting change from garage to conditioned living space. Many Aliso Viejo HOAs will approve a garage conversion more readily than a detached build because the street-facing elevation stays unchanged.

New Detached ADU

A new detached ADU on an Aliso Viejo hillside lot takes more site work than most people expect, and that’s the honest truth. The graded fill pads from the late-1980s and early-1990s development phases often require geotechnical review before we can pour a foundation, and some lots in the 92656 ZIP code sit on slopes where retaining walls and drainage plans are part of the permit package from day one. Budget $90,000 to $220,000 for a detached unit, with the higher end covering hillside caissons, upgraded fire-rated materials, and custom finishes. We build every detached ADU to current CAL FIRE ember-resistant standards, which Aliso Viejo’s High Fire Hazard Severity Zone designation requires.

Junior ADU & Interior Conversion

A junior ADU, or JADU, is the quiet option: no new foundation, no separate utility meter, and in most cases no HOA exterior review at all. We convert an existing bedroom, bonus room, or oversized laundry into a self-contained unit with its own entrance, kitchenette, and bath, starting around $45,000 depending on the plumbing work involved. This is a popular choice in Aliso Viejo for multi-generational households, especially in the tract homes where the floor plans are predictable and the electrical panels have enough capacity for a small induction cooktop and separate bath circuit. If you’re not sure whether your lot supports a detached build, a JADU is often the smartest first step.

Trusted Brands We Service in Aliso Viejo

We don’t put mystery brands off a van into your home. For Aliso Viejo projects we regularly specify windows and doors from Simonton, Ply Gem, and PGT, depending on the exposure and the fire-hardening requirements of your specific lot. These are brands you can look up, with published specs for things like Solar Heat Gain Coefficient and impact resistance, which matters when the Santa Ana winds hit those canyon-facing elevations. We keep local supply relationships across Orange County so lead times on windows, doors, and specialty hardware stay short, and we’ll show you the manufacturer’s warranty documentation before you sign anything. If you’d rather compare product lines, we’ll walk you through the differences at your kitchen table, not from a brochure.

Common Home Additions & ADU Problems We See in Aliso Viejo Homes

• HOA architectural review missed or skipped. Nearly every exterior project in Aliso Viejo’s master-planned tracts requires HOA approval before the city will even look at your permit application. We’ve been called in to fix stalled projects where the homeowner’s first contractor started framing without HOA sign-off, and the association issued a stop-work notice. The HOA step has to come first, and it takes two to six weeks depending on the board’s meeting schedule.
• Graded fill and retaining wall movement on hillside lots. Aliso Viejo was cut and filled in phases during the late 1980s and early 1990s, and we see fill slopes from that grading era settle unevenly. When we’re called to one cracked retaining wall on a hillside cul-de-sac, we frequently find the same failure mode at three or four adjacent homes built on the same grading phase. A room addition on a hillside lot needs to account for that soil behavior before the first pour.
• Original dual-pane window seals failing across entire tracts. The city’s window stock was installed between roughly 1985 and 2001, and those early dual-pane units are losing their argon fill at the same time. Fogged glass, condensation between panes, and warped sashes are tract-wide problems here, not one-off failures. When we do a room addition, we often find the existing windows on the adjacent wall need replacement too, and an integrated plan saves you money over doing it piecemeal.
• CAL FIRE ember-resistant standards on wildfire-adjacent lots. Aliso Viejo sits at the wildland-urban interface with the foothills above the city, and the state’s fire marshal maps put significant portions of the 92656 ZIP code inside a designated High Fire Hazard Severity Zone. New construction and major renovations have to meet stricter assembly and detailing requirements than flatland coastal Orange County cities. A contractor who doesn’t build to those standards in Aliso Viejo will fail inspection, and the rework isn’t cheap. We build to the higher standard from the start because it’s the law here, and because it’s the right way to protect a home.

Pricing for Home Additions & ADU in Aliso Viejo, CA

We Also Serve Cities Near Aliso Viejo

Barrett & Sons Construction serves the communities around Aliso Viejo, including Laguna Woods, Laguna Hills, Irvine, and Lake Forest. If you’re just outside the city line and planning an addition or ADU, call us at (877) 610-1318 and we’ll confirm coverage for your address. We also handle Kitchen Remodeling in Aliso Viejo and Bathroom Remodeling in Aliso Viejo for homeowners who want to tie an addition into a broader renovation.

FAQs - Home Additions & ADU in Aliso Viejo