Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Laguna
Home additions and ADU construction in Laguna typically runs $45,000 to $130,000 for a room addition and $90,000 to $220,000 for a detached ADU, with most projects taking 4 to 9 months from design to final inspection. The biggest variable in Laguna is not the framing or finishes; it’s the foundation work required by the post-tension slabs and expansive adobe clay that underlie nearly every tract home built here between the late 1980s and mid-2000s.
At Home Additions & ADU, our team has spent decades working in Laguna West and the surrounding planned communities. We know what the HOA architectural committees in Laguna approve, what Sacramento County and City of Elk Grove permit reviewers flag, and how to sequence the work so your project isn’t sitting half-finished while a design committee debates stucco color. Call us at (877) 610-1318 for a free estimate. Tom Barrett answers his own phone.
Why Barrett & Sons Construction Is Laguna’s Preferred Home Additions & ADU Company
We’re not a franchise dispatching strangers from three counties over. Tom Barrett founded this company in 1998, and his sons run the crews that show up in Laguna. When we tell you something about your post-tension slab or your HOA submittal, it’s because we’ve done it on your street or one just like it.
Laguna homeowners call us because we publish our name, address, and license number. You can look us up before you sign anything. Every job we take includes permits pulled and inspections signed, because the last contractor most people used told them permits were optional. We don’t work that way, and we never will.
The response time from our Sacramento dispatch office to Laguna is short. Tom’s crews live in the valley. We answer the phone 24/7 with a live person, not a voicemail box. When a Laguna customer calls on a Saturday morning, they get a human being who knows what a Laguna West stucco palette looks like.
Our Home Additions & ADU Services in Laguna
ADU Design & Permitting
Most ADU projects in Laguna start with paperwork before a single shovel hits the ground. We handle the full submittal packet: site plan, structural calcs, energy compliance, and the HOA architectural-review application if you live in Laguna West or another planned community. The HOA review typically adds 2 to 5 weeks to the timeline in Laguna, and we build that into the schedule from day one so you’re not surprised later.
Pulling permits in the Elk Grove/Laguna area means the exact parcel determines jurisdiction. Some lots answer to Sacramento County, others to the City of Elk Grove. We file with the right agency the first time. That saves you the headache of an approved permit that the wrong office has to transfer.

New Detached ADU
A new detached ADU in Laguna is a separate structure on its own foundation, which is actually an advantage on this soil. Because the adobe clay under Laguna expands and contracts with every wet and dry season, we isolate the new foundation from the existing post-tension slab. No structural connection means no differential movement stress cracking your new stucco.
Detached ADUs in Laguna run $90,000 to $220,000 depending on size, bathroom count, and whether you need new utility runs from the house. We use Simonton and Ply Gem windows on ADU projects because they hold up to the valley’s 110°F summer stretches and wide thermal swings.

Room Additions
Adding a room to a 1990s tract home in Laguna means matching the existing structure in ways that older cities don’t require. Your stucco color has to match the plan the HOA approved decades ago. Your roof pitch has to blend with the original hip roof. We know the Laguna West approved style list and we spec materials from day one that the design committee will sign off on.
Room additions in Laguna run $45,000 to $130,000. The structural engineering for a post-tension slab connection is one of the line items that makes Laguna builds different from a pier-and-beam addition in an older Sacramento neighborhood. We get the tendon locator out before any coring starts, every single time.

Junior ADU & Interior Conversion
A Junior ADU inside an existing Laguna home is often the fastest path to rental income or multigenerational living. Because you’re working inside the existing footprint, you avoid the slab matching issues entirely. The catch is that your HOA may still want to review the plans if it changes the outward appearance of the home. We file it all and keep the schedule moving.

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.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Laguna
We keep parts and materials in stock for the window brands most common in Laguna tract homes, including Simonton, Ply Gem, and PGT. If your addition needs windows that match the rest of the house, we can usually pull them without a long lead time. That matters when your HOA review already added two weeks to the calendar.
Common Home Additions & ADU Problems We See in Laguna Homes
- Cutting into a post-tension slab without a cable locator. Laguna’s tract homes almost all sit on post-tension concrete. Hit a tendon with a saw, and the sudden release can crack the entire floor and require slab replacement. We run a locator before every cut, no exceptions.
- Foundation work scheduled in December or January. Winter tule fog and rain saturate the adobe clay under Laguna, causing over-excavation and heaving. If the compaction report doesn’t pass inspection, you’re pouring money into a hole in the ground. We sequence excavation for the dry season whenever the project allows.
- Skipping the HOA architectural review before pulling permits. We’ve seen Laguna West projects get county approval and then get rejected by the design committee over stucco color or roof pitch. That’s a three-week delay and a redesign cost. We file the HOA packet first, then the permits.
- Connecting a new addition foundation directly to the existing slab. The adobe clay under Laguna moves. When the new and old foundations are tied together, differential movement shears the connection and cracks appear within two seasons. We isolate the new footing on every addition.
Pricing for Home Additions & ADU in Laguna, CA
Here’s what you’re looking at in Laguna, based on the work we’ve priced in this market:
| Project | Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| Garage Conversion | $30,000 - $80,000 |
| ADU Construction | $90,000 - $220,000 |
What moves the number in Laguna: whether your lot is post-tension (requiring isolation footings and tendon location), the HOA architectural fees and review windows, and the current cost of stucco and roofing materials that match your existing home. Every price change on our jobs arrives as a written change order before work continues. An allowance that isn’t on paper is a surprise waiting for a date. Call (877) 610-1318 and we’ll walk the property and give you a real number, not a guess.
We Also Serve Cities Near Laguna
Our Laguna crews work throughout the surrounding communities, including Elk Grove, Parkway, Florin, and Vineyard. If you’re planning an ADU or room addition nearby, we cover those markets with the same permitting and HOA experience. Same crew, same warranty, same written change orders.
Serving Laguna, CA - Our Local Coverage Area
We’re based in the Laguna 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 Laguna
Yes, in most Laguna planned communities the HOA design committee requires the new addition to match the original tract palette and roof geometry. We pull the approved color list for your specific subdivision before we order materials, and we spec a low-pitch hip roof when we need to blend with the original. Call (877) 610-1318 and Tom can tell you what your community’s standard is, often from memory.
Typically 2 to 5 weeks, depending on the association’s meeting schedule and whether your submittal is complete. We file the HOA packet before the county or city permit application, so the review runs in parallel with engineering. That keeps the total added time at the short end. For an exact schedule for your specific Laguna address, call (877) 610-1318. We’ll map it out with you.
Yes, and that’s the way we prefer to do it. The detached ADU gets its own isolated foundation, so we never have to cut into the existing post-tension slab. We run a cable locator on any area we’re working near anyway, but the structural approach keeps your original slab intact and avoids differential movement between the two structures.
A change order is a written document that tells you exactly what changed, what the new cost is, and what the new schedule is, signed by you and by us before the extra work starts. If we hit saturated clay during excavation and need deeper footings or soil mitigation, you get that in writing first. You approve it or you don’t. No surprise invoice at the end. That’s the Barrett & Sons rule on every job in Laguna.
Yes. We coordinate the structural engineer, the post-tension locator, the HOA architectural packet, and the county or city permit filing. On a recent second-story addition in Laguna West, our crew shored the existing slab, poured a new isolated footing, filed HOA paperwork with muted stucco swatches, and held the framing inspection until the county locator confirmed no tendons within six inches of our anchor bolts. You won’t be stuck trying to figure out which office needs which form. Call (877) 610-1318 for a free estimate and a schedule you can actually follow.
Contact Barrett & Sons Construction for Your Home Additions & ADU in Laguna
If you’re planning an addition or ADU in Laguna, we’ll come out, walk the lot, and tell you what we see. Real numbers, written down, with permits and HOA review handled. Call (877) 610-1318 today to schedule your free estimate. We live here, we work here, and we’ll be around long after the job is done.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Laguna & surrounding communities since 1998.







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