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CGI Home Additions & ADU: The Jacksonville Owner’s Guide
CGI home additions and ADU projects in Jacksonville typically run $45,000 – $130,000 for the full scope, depending on square footage, foundation work, and finishes. We write a fixed price before any work starts, and we name every material in that price so you can verify it yourself. Most homeowners realize a component has failed when they see water staining at a tie-in point, a door that no longer closes square, or a mini-split that cannot hold temperature in the new space. Those are the moments when a CGI addition stops feeling like part of the house and starts feeling like a problem attached to it.
This page covers how we match the right fix to your CGI build, what it costs in this market, and what we do differently during the work itself: drop cloths on the floors, shoe covers at the door, and a written price handed to you before the first tool comes off the truck. Graham Stein and our Jacksonville crew have worked on enough additions and ADUs to know that the failure is rarely one big thing. It is usually a sequence of small things that were never flashed, sealed, or fastened correctly the first time.
Which CGI Models This Applies To

CGI manufactures window and door systems, not the structural framing of an addition, so the compatibility question is usually about the tie-ins: how the new CGI windows and doors meet the original roofline, the ledger board, and the wall sheathing. On a Jacksonville addition, the CGI product that fails first is almost always a door threshold or a window flange, because those are the points where the installer had to bridge two different materials under time pressure.
To identify what you have, look for the AAMA label on the frame; it lists the series and the design pressure rating. CGI’s impact-rated lines, common in Florida, are built to Miami-Dade standards, and the glazing bead profile differs between the 500 series and the 900 series. A bead that is cracked, gapped, or caulked over with silicone tells you someone forced a universal part into a CGI-specific channel. We keep both OEM CGI components and quality aftermarket equivalents on hand for the common Jacksonville failure points. The aftermarket option matters when the original series is discontinued; CGI owners with older 300-series frames often learn that a direct OEM replacement no longer exists. In those cases, we match the sightline and the DP rating rather than pretending an off-the-shelf part is identical.
Styles & brands we work with







Signs Your CGI Home Additions & ADU Is Failing
- Water staining at the interior sill or baseboard. This means the pan flashing under the CGI door was never sloped, or it was sealed with a product that has failed after a few Florida wet seasons. The stain is the symptom; the real trouble is water traveling inside the wall cavity.
- A door that scrapes the top jamb or will not latch. The addition’s foundation has moved by a fraction, or the rough opening was framed too tight for the CGI frame’s tolerance. A door that fights you is telling you the opening has changed shape.
- Condensation between the glass panes. The seal on the insulated glass unit has broken. In Jacksonville’s humidity, this shows up as a haze that never wipes clean. The fix is a new IGU, not a new door, but it needs to be ordered to the correct thickness and spacer profile.
- Daylight visible around the frame perimeter. If you can see light at the jamb of a closed door, the shim spacing was inconsistent or the flange was not bedded in sealant. Air and water move through that same gap.
- Caulk that keeps cracking along the exterior trim line. Repeated cracking means the joint is moving more than the sealant can handle. Reapplying caulk is temporary. The joint needs a backer rod and a higher-movement sealant, or the flashing detail was skipped entirely.
See the difference
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After
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After
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AfterReplacement Cost & What’s Included

In Jacksonville, a full fix or rebuild on a CGI addition or ADU component runs from a few thousand dollars for a single door threshold and pan flashing replacement to $130,000 for a complete structural re-scope of a failing addition. Most of the jobs we see fall in the $45,000 to $130,000 range when the failure involves reframing a wall, replacing multiple CGI openings, or correcting a foundation slab that has settled past the door manufacturer’s tolerance.
The range depends on three things: whether the subfloor or slab needs work, how many CGI openings are involved, and whether the interior finishes have to come out to reach the framing. Our price includes the parts, the labor, the disposal, the flashing and sealant materials by name, and a photo of the clean-up before the crew leaves. It also includes the 365-Day Done Right Promise: if something we did is not right after the job is complete, we make it right. You will not get an allowance line item that quietly grows. You will get a written price before any work starts, and that price stays the price.
DIY or Call Us?
There are a few things you can safely check yourself: whether the weep holes at the bottom of the CGI frame are clear, whether the threshold screws are tight, and whether the door is out of level by more than an eighth of an inch. These observations help us quote accurately over the phone. What we do not recommend is pulling a threshold, removing a door panel, or attempting to re-flash an opening. A large impact-rated door is heavy, the glass can shatter if the panel torques during removal, and a dropped panel can do serious harm to a person or a pet. The most dangerous part is the spring-balanced hardware on certain lift-and-slide CGI units; removing those without the correct sequence puts hundreds of pounds of stored force against whoever is standing in the wrong place.
If you are uncertain whether the issue is cosmetic or structural, call (904) 643-6243. We will ask a few specific questions, tell you what we think over the phone, and schedule a free estimate if a site visit makes sense. No pressure, no same-day promise we cannot keep on planned work, just a straight answer.
FAQs

A properly flashed and installed CGI opening should hold up for 20 years or more in Jacksonville’s climate before the sealants and gaskets begin to show their age. What fails sooner is usually the installation detail, not the product itself, which is why we see fifteen-year-old additions with water damage at the threshold while the window frames above look nearly new. Call (904) 643-6243 if you are seeing signs of movement or moisture; we will tell you whether it is time to repair or time to monitor.
If the framing is sound and the CGI frame itself is intact, the tie-in can usually be repaired by removing the exterior trim, installing a correct pan flashing, and sealing the joint with a material rated for the movement Florida humidity creates. If the frame has twisted or the rough opening has shifted, replacement is the honest answer. Call (904) 643-6243 and we can talk through what you are seeing before we schedule anything.
A single threshold and pan flashing replacement typically takes one day. Replacing one impact door with proper tie-in work takes one to two days. A full re-scope involving multiple openings and interior drywall repair can run a week or more, and we will lay out the schedule in the written price before we start. Call (904) 643-6243 for a free estimate on your specific scope.
We keep the most common Jacksonville failure parts on the truck: thresholds, glazing beads, weeps, and flashing materials. Specific insulated glass units and certain CGI series hardware are ordered by size and series, which usually takes a few days. When we also work with KraftMaid, Cambria, and Silestone components on an addition, we treat the ordering the same way: named product, named lead time, written down. Call (904) 643-6243 and we will tell you what is in stock today.
If your CGI home addition or ADU is showing signs of failure, call Elmstead Remodeling Jacksonville at (904) 643-6243 for a free estimate. We will walk the site, write down what we find, and hand you a fixed price with every material named before anything starts. Name the material, name the day, name the price, then there is nothing left to wonder about.
Written by Graham Stein, Owner, Elmstead Remodeling Jacksonville at Elmstead Remodeling Jacksonville, serving Jacksonville and nearby areas.


