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GAF Home Additions & ADU: The Orlando Owner’s Guide
A GAF-backed home addition or ADU in Orlando typically runs $45,000 to $130,000 for a full permitted build, depending on square footage, foundation work, and whether you’re tying into the existing roofline or building a detached structure. We stock and install the GAF roofing and waterproofing components on most addition projects, and we can usually match your existing GAF shingle color and profile same week. Most Orlando homeowners discover a problem when they see water staining at the tie-in point where the new roof meets the old, or when an inspector flags the flashing after a hard summer storm.
If you’re reading this, chances are you either just got a quote that felt high, or you’re staring at a failed roof-to-wall connection on an addition someone else built. Either way, you want to know what it costs, what’s involved, and whether it’s worth pulling permits. We’ll walk through all of it straight.
One thing up front: Sawyer Remodel Orlando is an independent general contractor. We install GAF products regularly and know their specs cold, but we’re not affiliated with GAF corporate. That independence means we tell you when a GAF product is the right call and when a different approach saves you money without cutting corners.
Which GAF Models This Applies To
GAF makes a full lineup of roofing, underlayment, and flashing systems that matter on additions and ADUs. The most common products we work with on Orlando addition projects are Timberline HDZ and Timberline UHDZ architectural shingles, GAF Tiger Paw or Deck-Armor underlayment, StormGuard leak barrier for the valleys and eaves, and GAF’s Cobra ridge vent. If your existing roof has Timberline HDZ shingles and you’re adding square footage, the new section needs the same profile or the roofline will never look right from the street.
The compatibility gotcha most Orlando owners don’t expect: GAF changed the Timberline shingle profile slightly in the 2010s. An older Timberline from 2008 and a new Timberline HDZ from 2024 have a slightly different exposure and shadow line. If your addition ties into a roof that’s 15 or 20 years old, you’ll often need to either reroof the whole plane or accept a visible seam at the tie-in. We’ll tell you which is worth doing before you spend a dime.
On the ADU side, GAF’s EverGuard PVC or TPO membrane gets used a lot on low-slope Orlando ADU roofs, especially the flat-roof modern look that’s everywhere in Audubon Park and Colonialtown. That’s a different installation process entirely, and the failure points are different too.
OEM vs. Aftermarket for GAF Additions
For shingles and underlayment, we use OEM GAF products, full stop. Aftermarket shingles from another manufacturer technically work, but they void the GAF system warranty and the color match is never exact. For flashing and fasteners, we’re less brand-loyal. A high-grade aluminum step flashing from a reputable manufacturer does the job as well as GAF-branded flashing for less money. We’ll spec what matters and skip what doesn’t.
Styles & brands we work with
Signs Your GAF Home Addition or ADU Is Failing
Here’s what we see on Orlando addition projects, in order of how often we get the call.
- Water staining at the roof tie-in. This is the big one. The new roof meets the old roof at a valley or a wall, and the flashing wasn’t properly woven into the existing shingle course. We see this constantly on additions done by builders who didn’t pull a roof overlap back far enough. The fix is cutting back shingles, proper step flashing, and re-laying the course.
- Lifting or buckling shingles along the new ridge line. Orlando heat and humidity expands the decking, and a ridge that wasn’t vented properly with Cobra vent or an equal-mounted ridge vent creates back pressure. The shingles start to cup at the edges within two years.
- Granule loss concentrated in one section of the addition roof. If the new section was installed with a different batch number of shingles, the granule adhesion can differ. You’ll see a patch of the roof where the granules are washing into the gutters while the rest looks fine.
- Water pooling on a flat ADU roof after rain. Low-slope GAF EverGuard membrane roofs should drain completely. If water stands for more than 48 hours after a storm, the deck underneath is settling or the membrane was installed without enough slope at the cricket.
- Interior cracks at the connection point between the original house and the addition. This is less about GAF and more about the foundation, but it shows up on the roof line first. Differential settling between the old slab and the new slab pulls the roofline apart and the shingles crack along the seam.
Luca Romano has seen every one of these on Orlando addition jobs, and he’s honest about which ones are five-hour fixes versus which ones mean the original builder cut a corner you’re now paying for twice.
See the difference
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AfterReplacement Cost & What’s Included
For a full GAF-backed home addition in Orlando, you’re looking at $45,000 to $130,000. That covers plans, permits, foundation, framing, GAF roofing, drywall, electrical, HVAC tie-in, and finish work. A detached ADU with a GAF flat-roof membrane runs higher, typically $90,000 to $220,000 depending on whether you’re doing a garage conversion or a from-scratch build.
If the issue is just the roofing portion of an existing addition, the math changes. Replacing the GAF shingles, underlayment, and flashing on an addition roof runs $8,000 to $20,000 as a standalone roofing project. Repairing a failed tie-in flashing runs $400 to $1,800.
What drives the range on full additions: square footage, whether you need foundation piers (common in Orlando’s sandy soil zones near Conway and Belle Isle), and whether you’re tying into the existing truss system or building a separate structure. Every quote we write includes a line-by-line breakdown, so you see the GAF material cost, the labor, and the permit fees separately. The price we hand you is the price you pay. No change orders unless you change the scope.
DIY or Call Us?
If you’re just inspecting, you can do a lot from the ground. Check for granules in the gutter, look for shingles sitting proud of the roof line, and look at the tie-in point after a rain. Those are safe spot checks.
But here’s where we draw the line: any attempt to reseal a flashing, lift a shingle course, or re-nail a section of roofing means you’re on a ladder with a nail gun, working over a surface that’s slippery with Florida humidity. Roof work is dangerous, and a bad flashing repair is worse than no repair, because you trap the water behind the shingles. If you’re not comfortable on a 6/12 pitch in July, call someone who does this every week. That’s our job, and our 365-Day Done Right Promise means if the repair doesn’t hold, we come back and make it right on our dime. Call us at (850) 809-0306 and we’ll send someone out to look.
FAQs
A properly installed GAF Timberline HDZ roof on an addition should last 25 to 30 years in Central Florida, but the flashing at the tie-in point typically needs attention around year 12 to 15. The UV load and heat cycling in Orlando breaks down sealant faster than the shingles themselves. Call (850) 809-0306 if your addition roof is over a decade old and you haven’t had the flashing inspected.
Yes, in most cases. If the shingles are still in good shape and the leak is localized at the roof-to-wall or roof-to-roof seam, we can cut back the shingle course, install proper step flashing, and re-lay everything for $400 to $1,800. If the shingles around the tie-in are brittle or granule-bare, you’ll need a larger repair. We’ll show you photos either way before we touch anything.
A detached ADU with a low-slope GAF membrane roof typically takes two to three working days once materials are on site. A full shingle roof on an attached addition runs three to five days depending on the size of the tie-in and the tear-off. We schedule around Orlando’s afternoon storm pattern when we can, and we tarp everything at the end of every day.
We keep the most common GAF Timberline HDZ colors in stock in our Orlando inventory, including the darker tones that match most existing Orlando roofs. Special-order colors and the EverGuard membrane for flat ADU roofs usually take three to five business days from our supplier. You’ll know the lead time before we send you a contract, not after.
Good work doesn’t need a speech, it just needs to hold up. If your addition has a roof problem or you’re planning an ADU in Orlando and want a number that means something, call (850) 809-0306 for a free estimate. We’ll walk the property, point out exactly what’s failing, and hand you a written price before any work starts.
Written by Luca Romano, Owner & Lead Contractor, Sawyer Remodel Orlando at Sawyer Remodel Orlando, serving Orlando and nearby areas.
