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CGI Home Additions & ADU: The Miami Owner's Guide
If you're looking at a CGI home addition or ADU in Miami that's starting to show problems, you're likely facing a repair bill somewhere between $53,100 and $153,400 depending on the scope of work. That's the honest range we see for structural repairs, re-framing, and finishing work on existing additions and accessory dwelling units across Miami. Most homeowners discover the problem through visible cracking, a door that suddenly won't latch, or water staining along a roofline that used to be dry. We're Penhallow Remodeling Miami, and while we're an independent contractor not affiliated with CGI, we've repaired and rebuilt enough CGI additions and ADUs in this city to know exactly where they fail and what it costs to make them right.
Which CGI Models This Applies To
CGI home additions and ADU projects are not a single product line with a serial number stamped on a plate. They're built environments, and the failure point is rarely the whole structure. It's a specific joint, a settlement issue, a window opening, or an HVAC penetration. That said, what matters for any repair is the framing spec used when the addition went up, the tie-in method at the roofline, and the foundation detail. If you have original drawings from CGI, pull them. If you don't, we can usually identify the framing method within the first hour on site by looking at the wall assembly and the way the roof was tied to the existing structure. The components we install, whether structural lumber, sheathing, windows, or siding, are sourced to match or exceed what was originally used. For trim and finish work, we regularly use James Hardie siding and Therma-Tru doors, and we've installed Cambria and Silestone in Miami ADUs where countertops are part of a kitchenette repair.
Styles & brands we work with
Signs Your CGI Home Additions & ADU Is Failing
- Diagonal cracking at window or door corners. This is the classic symptom of differential settlement. In Miami, our expansive clay soil moves with wet-dry cycles, and an addition on a different footing profile than the main house will move independently. Cracks wider than a nickel mean the framing behind the drywall is carrying load it wasn't designed for.
- A roofline that doesn't line up. Stand across the street and look at the addition's ridge against the original roofline. If it's developed a sag or a hump, the tie-in connection has slipped or a beam is undersized. This gets worse every hurricane season.
- Water staining at the wall-to-roof intersection. CGI tie-ins are common leak points in Miami because wind-driven rain from three directions finds every gap in flashing. Staining you can see means water has been getting in for a while.
- Doors that stick seasonally. A door in the addition that latches fine in December but won't close in August is telling you the frame is moving. In Miami, the humidity swing alone changes dimensional lumber by enough to bind a door. It's often the first clue that something below the slab isn't right.
- Floors that slope or bounce. If a marble rolls across the ADU kitchen floor on its own, the subfloor has lost its level. Bounce underfoot suggests joists are under-spanned or a rim joist has been compromised by moisture.
See the difference
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After
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Before
AfterReplacement Cost & What's Included
The cost to repair or rebuild a compromised CGI home addition or ADU in Miami ranges from $53,100 to $153,400. The spread comes down to three things: whether the foundation needs remediation, how much framing must be replaced, and what level of finish you want on the back end. A small repair that opens one wall, replaces a header, and closes it back up sits at the lower end. A full structural correction, which might mean lifting part of the addition to re-set beams and re-tie the roofline, lands in the middle. A complete rebuild of an ADU with kitchenette and bath, finished to modern code with cabinet lines like KraftMaid or Wellborn, sits at the top. Before we pull a single board, you get a written price that covers demolition, structural work, in-wall mechanicals, finish work, and permitting. That number doesn't change unless we both agree in writing it needs to change.
DIY or Call Us?
You can safely do the detective work: take phone photos of crack patterns over a few weeks to see if they're moving, check your roof for lifted flashing after a storm, and watch whether doors bind on humid days. What you shouldn't do is open up a load-bearing wall to have a look. Structural work on an addition, especially in Miami where we build for 170 mph wind, is not a Saturday project. The wrong cut can drop a roof section on you or leave your home uninsurable. If you've got cracking, water intrusion, or a floor that moves, call (850) 988-7559. We'll bring a written estimate, not a sales pitch.
FAQs
A well-built addition or ADU in Miami should last 50 years or more, but the roof tie-in and foundation joint are the weak points. In our climate, flashing at the tie-in often needs attention every 8 to 12 years, and we recommend checking it before and after hurricane season. If you're under 15 years in and seeing significant movement, the original footings were likely undersized for our soil. Call (850) 988-7559 to have someone put eyes on it.
Yes, and in most cases repair is the right call. When the damage is localized, opening a wall, replacing a header or beam, and re-securing the tie-in is a one-to-two-week job. We only recommend a rebuild when the framing damage is widespread or the foundation itself has failed. We'll show you exactly what we found and what it means before you commit to anything.
A typical structural repair on a home addition takes two to four weeks from start to finish, including permitting and inspections. A full ADU rebuild runs eight to sixteen weeks depending on finishes. We'll give you a defined arrival window and a written schedule before work starts, and we keep you updated when something changes, which it sometimes does.
We stock the structural lumber, sheathing, fasteners, and flashing we use most often on our trucks, and we source finish materials from established trade brands. For ADU kitchens and baths, that means cabinetry from KraftMaid and Wellborn and countertops from Cambria and Silestone. You never have to chase down a part, and we handle all the ordering and lead times ourselves.
Written by Trevor Nash, Owner, Penhallow Remodeling Miami at Penhallow Remodeling Miami, serving Miami and nearby areas.
