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 Coral Gables
A permitted home addition or ADU in Coral Gables runs $45,000 to $130,000 for most projects, with garage conversions landing between $30,000 and $80,000 and new detached ADUs starting around $90,000. That’s the honest range we quote before anyone signs anything. The job takes longer here than in Kendall or Pinecrest because Coral Gables runs every exterior change through a Board of Architects review in addition to Miami-Dade permitting. If you’re planning a room addition, second story, or ADU, call Tom Barrett and his sons at (877) 610-1318. We’ll tell you what the city will and won’t approve before you spend a dollar.
We’ve worked these streets long enough to know that a Coral Gables addition isn’t a generic construction job. The 1920s Mediterranean Revival homes along Coral Way, the mid-century ranches off Bird Road, the infill builds near Biltmore Way: each one carries its own set of structural realities and code constraints. Our Home Additions & ADU team walks the site, reads the existing roofline, checks the tree canopy, and gives you a written scope that accounts for what this city actually requires.
Why Barrett & Sons Construction Is Coral Gables’s Preferred Home Additions & ADU Company
Tom Barrett founded Barrett & Sons Construction in 1998, and he still answers his own phone. His sons run the crews. When you call about an ADU in Coral Gables, you’re not reaching an out-of-state call center or a sales rep reading from a script. You get a live person, day or night, at (877) 610-1318.
Coral Gables homeowners tell us the same story: a previous contractor quoted one price, then showed up with change orders that doubled it. Our fix is simple. Every scope, every allowance, every price change arrives as a written change order before work happens. The permit inspector works for you, not for me. That’s why we pull permits on every eligible job and stand there when the inspections get signed.
We also know this city’s enforcement culture. The Board of Architects won’t rubber-stamp a flat tile profile on a Mediterranean Revival home. The tree ordinance won’t let you trench through a live oak root zone without an arborist report. We plan for those steps in the quote, not as surprises in month three.
Our Home Additions & ADU Services in Coral Gables
ADU Design & Permitting
Before any wall goes up, the design has to survive two reviews: the Coral Gables Board of Architects and the Miami-Dade building department. The Board cares about aesthetics, material palettes, roof profiles, and how the addition sits against the original George Merrick-era streetscape. Miami-Dade cares about wind loads and structural safety.
We’ve navigated this dual-permit process enough times to anticipate the objections before the first submittal. Our design package includes the elevation drawings, material schedules, and arborist documentation the city wants to see. That’s the difference between a permit in six weeks and a permit in six months.
Garage Conversion ADU
Converting an attached or detached garage into a permitted ADU is often the fastest path to rental income or an in-law suite in Coral Gables. The challenge here is the existing construction. Many garages in this city are Oolitic limestone or hollow clay tile block from the 1930s and 1940s. That material requires diamond-blade cutting, epoxy-anchored ledgers, and specific waterproofing details that modern concrete block doesn’t.
Our crew recently converted a 1930s garage on Coral Way into a permitted ADU. The Board of Architects required a matching barrel-tile roof profile and stucco finish before Miami-Dade would sign off on the impact-rated window assemblies. The punch list closed only after the city arborist confirmed no banyan roots were disturbed by our site prep for the new utility trench. That’s what a compliant job looks like in this city.
New Detached ADU
A new detached ADU gives you a clean slate, but the Coral Gables Board of Architects will still hold that building to the Mediterranean Revival vocabulary. Arched openings, stucco finishes, barrel tile, and facade proportions all get scrutinized. Our approach is to design the ADU so it reads as a natural extension of the main house, not a prefab afterthought.
Foundation work matters more here than most places. Coral Gables sits on a very shallow water table. We plan slab elevations and drainage so seasonal flooding and wet-season storms don’t put standing water at your new ADU’s threshold.
Junior ADU & Interior Conversion
When you’re working within an existing footprint, like a Junior ADU built out of a finished basement, bonus room, or attached wing, the Board of Architects review can be lighter. But “lighter” in Coral Gables still means scrutiny. Any change to the exterior envelope, fenestration, or roofline triggers review. Interior-only conversions move faster, especially when the exterior stays untouched.
We’ve completed these in homes near Coral Terrace and the neighborhoods off LeJeune Road, and the pattern is consistent: clear drawings, honest material specs, and a written change order process keep the job moving.
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.
Trusted Brands We Service in Coral Gables
When your Coral Gables addition calls for impact windows and doors, we install named brands like PGT, CGI, and Ply Gem. These are products engineered to meet Miami-Dade’s post-Andrew wind code, and we can hand you the spec sheets before you sign. If you’re replacing a window on a Mediterranean Revival home, we’ll match the frame profile and finish so the Board of Architects doesn’t flag it. Ask anyone on your street, or look up the license number yourself. We’re not installing mystery brands off a van.
Common Home Additions & ADU Problems We See in Coral Gables Homes
- Board of Architects rejection for roof tile mismatch. A contractor specifies a flat concrete tile profile because it’s cheaper. The Board rejects it because the home sits in a Mediterranean Revival district that requires barrel tile. The project stalls for months. We spec the correct profile from the first drawing.
- Missing arborist report halts excavation. Coral Gables protects its mature banyan and live oak canopy with a strict tree ordinance. If you break ground near a protected tree without a certified arborist report, the city can stop the job. We order that report before site prep begins.
- Cheap quotes that omit impact-rated assemblies. Some bids leave out impact windows, engineered roof-to-wall connections, and proper shear walls in order to look cheaper. Those elements are not optional under Miami-Dade code. A compliant quote includes them in writing.
- Water intrusion at the foundation line on older masonry homes. Oolitic limestone and hollow clay tile wick moisture differently than modern CMU. Without proper waterproofing and drainage detailing, a new addition can bring dampness into the original structure. We address this during the foundation phase, not after the drywall is up.
Pricing for Home Additions & ADU in Coral Gables, FL
Here’s what a compliant project actually costs in Coral Gables. These ranges reflect the dual-permit process, hurricane-rated assemblies, and the labor involved in working with older masonry construction.
| Project Type | Coral Gables Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
What changes your final number: the Board of Architects review scope, the arborist and drainage work, the floor plan, the finish level, and whether you’re working on a 1930s masonry home or a newer build. We give written line-item quotes so you can see exactly where the dollars go. Call (877) 610-1318 for a free estimate. No trip charge inside the county, and a permanent 10% senior and veteran discount applies.
We Also Serve Cities Near Coral Gables
Our crews work throughout the neighborhoods around Coral Gables, including Coconut Grove, Glenvar Heights, South Miami, and Coral Terrace. If you’re in one of those communities and planning a home addition or ADU, the same permit and building-code realities apply. Learn more about how we approach Coral Gables projects and the surrounding area, then call us to talk through your specific site.
Serving Coral Gables, FL - Our Local Coverage Area
We’re based in the Coral Gables 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 Coral Gables
The Board of Architects review typically adds 4 to 10 weeks to your Coral Gables ADU timeline, depending on the project’s scope and whether the initial submittal triggers design revision requests. You can shorten that window by submitting elevation drawings that already match the Mediterranean Revival vocabulary: barrel tile, stucco, arched openings, and facade materials consistent with your home’s original character. Call (877) 610-1318 and we’ll tell you honestly whether your design is likely to sail through or hit resistance.
Every permitted structural element in Coral Gables must meet Miami-Dade County’s post-Hurricane Andrew wind code, which is among the strictest in the nation. That means impact-rated window and door assemblies, engineered roof-to-wall connections, and shear wall details that resist uplift and lateral loads during a storm. A cheap quote that omits these elements will fail inspection. Ours include them as a line item, in writing, before work begins.
In most cases, you can convert an existing garage into an ADU with minimal exterior changes, especially if the garage door stays in place or is replaced with an impact-rated assembly that matches the existing facade. However, any alteration to the roofline, stucco, window openings, or exterior finish is subject to Board of Architects review. Interior-only conversions move faster. Call (877) 610-1318 and we’ll walk the site and tell you what the city will require.
Yes. Coral Gables sits on a shallow water table that worsens during the wet season and after tropical storms. A properly planned ADU foundation in this city includes slab elevation planning, perimeter drainage, and waterproofing details that keep water from wicking through the slab or standing at the threshold. We address this during the foundation phase and document it in writing so the inspector signs off without drama.
Yes. We coordinate the certified arborist report and any tree relocation permit the city requires before a crew breaks ground near protected canopy. Coral Gables’ tree ordinance is enforced, and missing this step can halt excavation for weeks. We include it in the written scope so there’s no surprise stop-work order mid-project. Call (877) 610-1318 for a free estimate on your Coral Gables addition or ADU.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Coral Gables and the surrounding communities since 1998.