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GAF Home Additions & ADU: The Miami Owner’s Guide
If you’re planning a home addition or ADU in Miami and want GAF products on the roof, we install them. A full GAF-equipped home addition in Miami runs $53,100 – $153,400 depending on square footage, foundation work, and whether you’re adding a kitchen or bath. An ADU with GAF roofing typically lands between $106,200 and $259,600 once you factor in utility connections and impact-rated windows. Most homeowners call us after realizing their existing contractor can’t pull permits or won’t put GAF materials in writing, and that’s usually when the real questions start.
We’re Sawyer Remodel Miami, an independent general contractor. We’re not affiliated with GAF, but we install their roofing systems regularly and stand behind the work with our own 365-Day Done Right Promise. Luca Romano runs our crews, and he’s been swinging hammers long enough to know that a home addition is only as good as the roof over it. In Miami, that roof earns its keep every hurricane season.
Which GAF Models This Applies To
GAF makes three roofing lines you’ll see on Miami additions and ADUs: the Timberline series (architectural shingles), the Royal Sovereign line (three-tab, budget-conscious), and the EverGuard TPO/PVC membrane system for flat or low-slope roofs common on modern ADU designs. The Timberline HDZ and Ultra HDZ are what we install most on pitched roofs. They’re rated for 130 mph winds, which matters in Miami-Dade where code requires that rating or better.
Here’s the compatibility gotcha most people miss: GAF’s warranty on the Timberline HDZ only reaches full coverage when installed as part of a complete GAF system, not just shingles. That means GAF underlayment, GAF leak barrier, and GAF starter strips. If a contractor slaps GAF shingles over generic felt, you get the shorter material warranty, not the full 50-year system warranty. We install the full system because anything less is leaving money on the table. For flat-roof ADUs, the EverGuard TPO comes in 45, 60, and 80 mil thicknesses. In Miami’s sun, we spec 60 mil minimum. The heat breaks down thinner membrane faster than any other climate factor down here.
Styles & brands we work with
Signs Your GAF Home Additions & ADU Is Failing
- Granule loss in gutters. If you’re finding dark granules collecting at downspouts within the first five years, the shingle surface is breaking down faster than it should. In Miami, this usually means the roof is taking too much direct sun or the attic isn’t venting heat properly.
- Curling shingle edges on the sun-facing slope. The south and west exposures bake all day here. Once shingles start curling, water gets underneath and the underlayment takes damage that shingles alone were never rated to stop.
- Water stains on the new ceiling drywall. A fresh addition shouldn’t show ceiling stains. If it does, the flashing at the tie-in where the new roof meets the original house is usually the culprit. GAF shingles can’t fix a bad flashing detail.
- Lifting shingles after a storm. Miami gets enough wind that shingles that lift once rarely reseal properly. The adhesive strip loses its grip, and the next storm takes more. This is the number one failure we see on ADU roofs within the first two years.
- TPO membrane pulling at the seams. On flat roofs, the heat expands the membrane daily. If the seams weren’t heat-welded properly, they start opening. Water sitting on a Miami flat roof in August finds every gap.
See the difference
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AfterReplacement Cost & What’s Included
A GAF roof replacement on a home addition or ADU in Miami runs $9,440 – $23,600, with most ADUs landing between $12,000 and $18,000 depending on roof size, pitch, and whether we’re replacing decking. Here’s the breakdown:
- Full GAF Timberline HDZ system on a 400 – 600 sq ft ADU: $9,440 – $14,750 installed
- Full GAF system on a 600 – 900 sq ft addition: $12,500 – $18,400 installed
- GAF EverGuard TPO on a flat ADU roof (60 mil): $10,500 – $16,800 installed
- Decking replacement if the existing wood is rotted: add $1,800 – $4,200
Every quote includes tear-off, disposal, new flashing, GAF underlayment and leak barrier, the shingles or membrane, and labor. We put the price in writing before any work starts, and the number on the invoice is the number you approved. The 365-Day Done Right Promise covers our workmanship for a full year after install.
DIY or Call Us?
Roofing is not a DIY project in Miami. The combination of height, heat, and hurricane-code requirements means a missed nail pattern or a bad seam is a leak waiting for the next storm. Even inspecting a roof yourself is risky on a pitched addition if you’re not comfortable on a ladder. What an owner can do safely: check gutters for granules after storms, look for visible curling from the ground with binoculars, and keep an eye on ceilings after heavy rain. If any of those signs show up, call us at (850) 801-8046. We’ll send a background-checked, uniformed crew with a written quote before any tools come off the truck.
Good work doesn’t need a sales pitch. We’d rather show you the condition of the roof and give you a number than convince you of anything over the phone. Luca Romano and our crew have been working Miami long enough to know that an honest roof inspection beats a sales presentation every time.
FAQs
A properly installed full GAF Timberline HDZ system should last 25 – 35 years in Miami, not the 50 years the warranty implies. Our UV exposure and storm cycles take real years off shingle life. That’s still solid performance, but anyone promising five decades on a Miami roof is stretching the truth. Flat TPO roofs realistically last 15 – 20 years here before heat degradation becomes visible. Call (850) 801-8046 for an exact assessment of your specific roof.
Yes, if the damage is isolated, roof repair in Miami runs $470 – $2,125. Missing or lifted shingles, a failed boot around a vent pipe, or a small flashing failure are all repairable. If the shingles are widespread curling, granule loss, or the underlayment is compromised, repair becomes throwing money at a problem that needs replacement. We’ll tell you the truth either way, with photos of what we found before you commit to anything. Estimates are free.
A standard ADU roof with tear-off runs one to two days for our crew, assuming no decking replacement. If we’re replacing rotted decking or the existing roof has multiple layers to remove, it can stretch to three days. We give you a live arrival time and before-and-after photo updates through the whole job. The written quote includes a timeline before you sign anything.
We order GAF materials directly through local Miami supply houses for each project, including Timberline HDZ, underlayment, and EverGuard TPO. We don’t warehouse inventory because roofing materials degrade in Florida heat when stored too long. What we do is confirm material availability and pricing before scheduling, so there’s no surprise delay after you approve the job. We also work with roof materials from CertainTeed and Owens Corning, plus James Hardie siding, KraftMaid cabinetry, and Cambria or Silestone countertops on the build-out side.
No. The written price you approve is the price you pay. The only exception is if we open the roof and find rotted decking that no one could see before tear-off. If that happens, we stop, show you photos, and get your written approval before adding anything to the invoice. The Relay Visibility Guarantee means you see everything before it happens. Call (850) 801-8046 to schedule your free estimate and get a number in writing.
Written by Luca Romano, Owner & Lead Contractor, Sawyer Remodel Miami at Sawyer Remodel Miami, serving Miami and nearby areas.
