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CGI Home Additions & ADU: The Houston Owner's Guide
CGI home additions and ADU construction in Houston typically runs $45,000 to $130,000 for a completed addition, with standalone ADUs landing between $90,000 and $220,000 depending on foundation work, utility rough-ins, and finish level. We stock and install the structural and finish components that make these projects hold up in Houston's climate: treated sill plates, hurricane-rated tie-downs, moisture barriers, and the trim, door, and window packages that keep a new space sealed tight. Most owners reach out after a smaller part fails – a warped exterior door, a rotted sill plate, a window that no longer seals – and discover the fix requires opening up a wall rather than swapping a single component.
Bradford Remodeling Co Houston is an independent contractor, not affiliated with CGI. We work with CGI-compatible structural and finish materials on additions and ADUs throughout the Houston area, and we spec every job against the same standard: a written price before work starts, a documented scope, and a full-year guarantee on the completed project.
Which CGI Models This Applies To
CGI's product line for residential additions and ADUs covers window and door systems, impact-rated glass packages, and the exterior envelope components that carry the load in a Houston addition. The compatibility question usually comes down to the window and door series: CGI's Estate Collection and Targa Series are common on higher-end Houston additions and detached ADUs, and each series has a different frame depth and anchoring pattern. You cannot swap a Targa window into an opening framed for an Estate unit without reworking the rough opening and re-flashing the perimeter – the frame profiles are not interchangeable.
Identification is straightforward if you know where to look. The CGI product label is printed on the frame edge, visible when the sash is opened fully. It lists the series name, the glass package, and the manufacturing code. If the label is gone or painted over, measure the visible glass width and the frame depth, and check the corner construction – Estate frames use a reinforced corner key; Targa uses a narrower, lighter profile. For finish materials on the addition itself, CGI-compatible doesn't mean proprietary: we install James Hardie siding, Therma-Tru exterior doors, and GAF roofing on CGI-spec additions because those manufacturer warranties back the same span of coverage we guarantee on the work. KraftMaid, Cambria, and Silestone are also brands we stock for interior finish work on these projects.
Styles & brands we work with
Signs Your CGI Home Additions & ADU Is Failing
What breaks first, and why
- Water staining at the bottom corners of windows and doors. This is the classic Houston failure. The flashing tape degrades, wind-driven rain gets behind the frame, and the stain shows up months before the rot does. By the time you see the stain, the substrate behind the drywall is already wet.
- A door that suddenly drags or won't latch. Houston's clay soil expands and contracts with moisture, and an addition's foundation moves with it. A dragging door isn't a hinge problem – it's the frame racking because the sill plate or the foundation has shifted. Forcing the door closed makes the frame worse.
- Gaps opening at the exterior wall-to-roof connection. Where the addition ties into the original roofline is the most common water entry point. If you can see daylight or a continuous gap from inside the attic or crawl space, the tie-in flashing has failed or was never installed correctly.
- Windows with condensation between the glass panes. The seal on an insulated glass unit fails over time, and Houston humidity accelerates it. A failed seal doesn't just fog the glass – it means the window has lost its insulating gas fill, and the humidity is now hitting the frame from inside.
- Mold or musty smell that never goes away. Behind the baseboard, along the sill plate, inside the wall cavity – this is water that found a path and stayed. It usually traces back to a failed moisture barrier or a flashing detail that was skipped during the original build.
See the difference
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After
Before
After
Before
AfterReplacement Cost & What's Included
Home additions in Houston: $45,000 to $130,000. A simple bump-out addition with standard finishes lands near the low end; a full primary-suite addition with a bathroom, walk-in closet, and premium finishes pushes toward the high end. ADU construction: $90,000 to $220,000, driven by whether the ADU is attached or detached, the foundation type (pier-and-beam versus slab), and the utility tie-in distance from the main house. Garage conversions run $30,000 to $80,000 depending on whether you're adding a bathroom, upgrading the electrical panel, or just finishing the shell.
Line-item breakdown for a mid-range Houston addition
- Foundation and framing: $18,000 – $35,000
- Roof tie-in and exterior envelope (siding, windows, doors, flashing): $10,000 – $22,000
- Rough plumbing and electrical: $6,000 – $15,000
- Insulation and drywall: $4,000 – $9,000
- Finish work (flooring, trim, paint, interior doors): $7,000 – $18,000
- Permits and inspections: $1,500 – $4,000
Every Bradford Remodeling Co Houston project includes a written price before tools come out, a line-item scope, and the 365-Day Done Right Promise: if anything we built fails within a year, we return and correct it at no charge. The price we put in writing is the price you pay – no numbers that move at the door.
DIY or Call Us?
If you're seeing water staining or a dragging door, there are things you can safely check. Verify that gutters are clear and downspouts are discharging away from the addition's foundation. Check that the soil around the perimeter slopes away from the slab – Houston owners fix a surprising number of water issues just by regrading the flower bed. And read your CGI product label so you know exactly which series you have before you start calling for parts.
What you should not do is cut into a wall or pull a window to diagnose the problem yourself. A Houston addition's framing carries lateral load from wind and the roof tie-in, and opening the wrong section compromises the structure. The same goes for any electrical or plumbing rough-in work – that is code-regulated for a reason. Curtis Lane and our crews have run additions across Houston long enough to know exactly where the water gets in and where the framing fails first. Call (940) 289-7658 and we'll walk the job with you and put the scope in writing.
FAQs
A properly built addition in Houston should last 50-plus years for the structure, but the exterior envelope – flashing, sealants, weather barriers, window and door seals – has a realistic service life of 10 to 20 years before something needs repair. Porches, attached ADUs, and additions that face sustained afternoon sun and driving rain from the southeast will need envelope maintenance sooner. Call (940) 289-7658 and we'll inspect your addition's envelope and tell you honestly what's left in it.
Some failures can be repaired – a dragging door can often be corrected by re-shimming the frame and adjusting the hinges, and a failed insulated glass unit can be replaced without pulling the whole frame. But if the frame itself has rotted or the rough opening has shifted, partial repair just buys you a year and the problem returns. We'll tell you which one you have and put the repair price in writing either way.
A straight-forward bump-out addition in Houston runs 3 to 5 months from foundation work to final paint. A detached ADU with a bathroom and full utility runs 5 to 8 months. We schedule permits first, stage materials around Houston's supply lead times, and give you a written timeline with the scope – so the date on paper is the date we hit.
We carry the common CGI-compatible components on our trucks – flashing tapes, sealants, sill pans, and frame shims – and we order series-specific windows, doors, and trim packages directly through our supplier network. You don't chase parts. We spec them, order them, and verify they match your existing series before the install crew arrives.
Straight scope, straight number – that's the whole conversation.
Written by Curtis Lane, Owner, Bradford Remodeling Co Houston at Bradford Remodeling Co Houston, serving Houston and nearby areas.
