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CGI Home Additions & ADU: The Ventura Owner’s Guide
We install and build home additions and ADUs across Ventura using materials and methods that hold up to coastal air, and the typical project here runs $45,000 to $130,000 for an addition, or $90,000 to $220,000 for a full ADU. Most CGI homeowners contact us when a specific part of their home addition or ADU build has failed or is failing: a door that no longer seals, a window that fogs between panes, a stair stringer that has started to separate, or flashing that pulls away from the stucco. The first sign is usually small, and then it isn’t.
We’re an independent service provider in Ventura, not affiliated with CGI. What that means for you: we match replacement parts to your existing CGI setup, write the price down before any work starts, and stand behind the finished job with our 365-Day Done Right Promise.
Which CGI Models This Applies To
CGI home additions and ADUs in Ventura typically fall into a few repeatable configurations: attached single-story additions, detached ADUs with a single entry, and garage conversions that share a wall with the main house. The parts that fail first are almost always at the transitions: door thresholds, window jambs, the bottom plate where framing meets slab, and the flashing where a new roofline ties into the old one.
To identify the right replacement part for your CGI build, look for the small manufacturer label on the inside edge of the window frame or the top of the door slab. It will list a series code and a manufacturing date. If the label is gone, measure the rough opening width and height, plus the jamb depth, and take a photo of the existing hardware before calling us. For CGI specifically, the window and door series dictate which replacement sash, weatherstripping, or threshold profile fits. Mixing series is where most DIY part matches go wrong. We stock the common CGI-compatible thresholds, door sweeps, and window balances on our trucks in Ventura, and we can order the less common series-specific parts, usually in three to five business days.
Styles & brands we work with
Signs Your CGI Home Additions & ADU Is Failing
- A door that drags or won’t latch in winter. Ventura’s winter moisture swells door slabs and shifts slabs slightly. If the reveal around the door is uneven, the jamb or threshold has moved, not just the slab.
- Fog between double-pane window glass. The seal has failed. In coastal Ventura air, a failed seal moves fast from a small fog patch to full clouding within a season. The sash or the glass unit needs replacement, not a quick clean.
- Water staining at the bottom of a wall or baseboard. On ADUs especially, this points to flashing that pulled away from the stucco or a threshold that no longer channels water away from the door. By the time the staining shows, the water has been moving for a while.
- A floor that feels soft or springy near an exterior door. This is usually the subfloor or bottom plate around the threshold. In a garage conversion, it’s often the original slab edge wicking moisture into the new framing.
- A step or stringer that creaks and flexes. On raised foundations common to older Ventura lots near the Pier and Midtown, the connection between the addition’s stairs and the ledger board loosens over time. The creak is the fastener working free.
See the difference
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AfterReplacement Cost & What’s Included
For targeted replacements on a CGI home addition or ADU in Ventura, most jobs land between $3,000 and $10,000 depending on what failed. A door threshold and flashing repair typically runs $1,200 to $3,000 installed. A window sash or glass unit replacement runs $400 to $1,800 per opening. Full stair stringer or landing replacement runs $2,500 to $7,000. If the failure is structural, a broader repair on part of the addition starts closer to the $45,000 range for a section rebuild and goes up from there.
Every quote from us is a written price before any work starts. That price includes the specific part, the labor to remove the failed section, the install, the disposal, and the clean-up. We use drop cloths on every interior path, shoe covers at the door, and quiet tools during family rest hours where the job allows. If it’s not done right, the 365-Day Done Right Promise covers it.
DIY or Call Us?
There are two things you can safely check yourself. One: look at the label on the window or door, write down the series code, and measure the opening. That saves us a trip. Two: check whether the problem is just a loose hinge screw or a worn weatherstrip. Those are simple. But anything involving a door that has dropped, a window with failed glass, a stair stringer that flexes, or water that has reached framing is not a weekend fix. High-tension door springs on old CGI hardware can release suddenly and cause serious injury, and a flashing repair done wrong just moves the water somewhere you can’t see. Put it in writing before the first board moves. If you’re in Ventura and the part is failing, call us at (341) 218-4316 and we’ll come look.
FAQs
Most CGI door thresholds, window seals, and flashing have a realistic service life of 10 to 15 years in Ventura’s salt air, though south-facing openings wear faster. We see the most failures on the west walls, where afternoon sun and ocean wind work on everything.
It depends on the part. Weatherstripping, door sweeps, and hinges are repairable. Failed window glass, rotted thresholds, and separated flashing usually need replacement, because a patch just moves the failure point further along the wall. Call (341) 218-4316 for an honest read.
A door threshold or window sash replacement is usually a half-day job. Flashing or stair work can take two to three days. Structural rebuilds on part of an addition take longer, and we lay out that sequence in the written price before the crew starts.
We keep the common thresholds, sweeps, and window balances on our trucks for Ventura jobs, and we can order series-specific CGI parts within three to five business days. We also work with KraftMaid, Cambria, and Silestone when the repair involves cabinetry or surfaces.
Written by Graham Stein, Owner, Elmstead Remodeling Ventura at Elmstead Remodeling Ventura, serving Ventura and nearby areas.
