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CGI Home Additions & ADU: The Dallas Owner’s Guide
If you have a CGI home addition or ADU and part of it is failing, you’re likely looking at a repair that runs between $45,000 and $130,000 in Dallas depending on what failed, how far the damage spread, and what code requirements your neighborhood triggers. We work on CGI-built additions and ADUs across Dallas from Lake Highlands to Kessler Park, and we stock or can source CGI-compatible structural parts, framing materials, and finish components quickly. Most owners first notice the problem as a door that no longer closes square, a hairline crack running along a ceiling seam, or water staining where the addition meets the original house.
We are an independent Dallas remodeling contractor, not affiliated with CGI. That said, we have worked on enough CGI additions and ADUs to know their construction patterns, their common failure points, and the right way to match a repair without making the joint worse.
Which CGI Models This Applies To
CGI home additions and ADUs in Dallas are typically built in one of two ways: a conventional stick-built addition framed on site, or a prefabricated module set onto a prepared foundation. The stick-built CGI additions share framing dimensions with standard Dallas residential construction, which means most structural lumber, connectors, and sheathing are readily available. The prefabricated CGI units are trickier: they often use engineered details at the marriage wall (the seam where two modules meet) and at the roofline that require matching the original specification exactly, not just whatever is on the shelf at the lumberyard.
Before you start buying parts, check for a metal identification plate or sticker, usually inside a closet or near the electrical panel on the addition. It will list the model or series number, the year built, and sometimes the original installer. That information tells us whether we are dealing with an on-site CGI build or a factory module. For prefabricated units, we always recommend OEM-equivalent engineered components at the marriage wall and roof-to-wall connection points. For stick-built CGI work, quality aftermarket lumber and Simpson Strong-Tie connectors are structurally identical and often easier to source same-week in Dallas. The compatibility gotcha we see most often: prefab CGI units from before 2015 frequently use a narrower stud profile at the marriage wall than current Dallas code allows, so swapping in a standard 2×6 without checking creates a 1.5-inch step in the wall that nobody notices until the drywall goes up.
Styles & brands we work with
Signs Your CGI Home Additions & ADU Is Failing
- A door that sticks or swings open on its own. This usually means the addition has settled unevenly, or the floor system has deflected. In Dallas’s clay soil, which expands and contracts dramatically with moisture, we see this more often on the south and west sides of additions where afternoon sun bakes the foundation perimeter.
- A crack running along the ceiling where the addition meets the original house. This is the classic CGI connection-point failure. The original house and the addition move at different rates, and the crack widens and narrows with the seasons. If it opens past 1/8 inch, you want a professional to check the structural connection, not just caulk over it.
- Water staining on interior walls or the ceiling, especially after a Dallas gully-washer. CGI prefab roofs often use a specific membrane lap detail at the ridge and at the transition to the main house. If that lap was not sealed correctly or has aged out in the Texas sun, water gets in and travels along the framing.
- Soft flooring or a slight bounce near the exterior walls. In an ADU with a raised floor, this points to a rim joist or floor beam issue. In Dallas, we also check for termite damage in these areas, because the warm, humid months are hard on untreated wood near grade.
- Windows or doors in the addition that are harder to open than they were a year ago. This is often the first early sign of foundation movement under the addition. It is easy to dismiss as humidity, but Dallas’s blackland prairie clay means even a modest settlement shows up at the corners first.
See the difference
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AfterReplacement Cost & What’s Included
A full CGI home addition replacement in Dallas typically runs $45,000 to $130,000, and an ADU construction falls between $90,000 and $220,000. Those are wide ranges because the variables are real: foundation condition, whether you need to match rooflines to the existing house, current Dallas permit and inspection fees, and whether the original CGI framing is salvageable or must be rebuilt entirely. A small, contained repair, say re-flashing a roof transition or sistering a few floor joists, lands at the lower end. Anything involving foundation work, full roof replacement, or re-engineering the connection between the addition and the house pushes toward the top.
Every quote we give in Dallas is a written, line-item price before any work starts. You will see the parts cost, the labor cost, and the permit line separate. If the final invoice differs from that written number, it will be because you changed scope, not because we re-priced the job at the end. The work carries our 365-Day Done Right Promise in writing. If something we touched fails within a year, we come back and fix it at no charge. No service call fee, no re-inspection fee, no argument.
DIY or Call Us?
Some things on a CGI addition you can check yourself without risk: the caulk lines around windows and exterior joints, the condition of weatherstripping, visible gaps at trim, and whether downspouts are directing water away from the foundation slab. Those are legitimate homeowner jobs. But anything involving the structural connection between the addition and the original house, any roofing membrane work, or any electrical inside a prefab module is not a DIY project. Prefab CGI units often run wiring through chases inside the wall system, and cutting into the wrong channel is dangerous. Structural work on a failing marriage wall can also fail suddenly if unbolted in the wrong sequence, which puts you and anyone in the addition at risk.
If you are not sure which category your problem falls into, call us at (940) 204-5368 and describe what you are seeing. We will tell you honestly whether it is something you can handle yourself or whether a trained professional should look at it. Either way, you get a straight answer.
FAQs
A well-built CGI addition with proper foundation work and maintained roofing should last 40 to 60 years before needing major structural attention, though Dallas’s clay soil and summer heat mean the roof membrane and exterior caulking typically need replacement every 10 to 15 years. The structure itself lasts far longer than the weather-exposed components. Call (940) 204-5368 if you want a professional assessment of where your addition is in that lifespan.
Often yes, especially if the problem is caught early. A cracked ceiling seam, a sticking door, or localized water staining can usually be repaired without rebuilding the addition. The exception is when foundation movement has compromised the connection points or when water damage has rotted structural framing. Call (940) 204-5368 for a written evaluation before you assume the worst.
A typical repair such as re-flashing a roof transition or sistering floor joists takes one to three days on site. Larger structural remedies or full section replacements can run two to four weeks depending on permit timing with the City of Dallas and whether we need to match finishes inside the existing space. We give you a written schedule before we start, and we hold to it.
For stick-built CGI additions we stock the common structural connectors, framing lumber, flashing materials, and fasteners on our trucks and can start most repairs the same visit. For prefabricated CGI modules we sometimes need to order specific engineered components, which usually arrive within a week in Dallas. Call (940) 204-5368 and we will tell you which category your job falls into before you spend a dollar.
Written by Trevor Nash, Owner, Penhallow Remodeling Dallas at Penhallow Remodeling Dallas, serving Dallas and nearby areas.
