Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
GAF Home Additions & ADU: The West Palm Beach Owner’s Guide
GAF home additions and ADU construction in West Palm Beach typically runs $45,000 – $130,000 for a full addition, while a standalone ADU (accessory dwelling unit) lands between $90,000 and $220,000 depending on size, foundation work, and finish level. We install GAF roofing and weatherproofing materials on every addition we build, and we can usually start your written estimate within a few days of the first call.
Most West Palm Beach homeowners don’t wake up planning an addition. They discover it the day the home office stops working because a third child needs a bedroom, or when an aging parent needs to live closer but not in the same hallway. What they’re really looking for isn’t a construction crew. It’s a written number, a start date they can plan around, and a roofline that won’t leak during the summer afternoon downpours we get off the Atlantic. That’s the job we do.
Which GAF Models This Applies To
Every addition and ADU we build in West Palm Beach gets GAF roofing products specified before the first permit is pulled. The exact product line depends on the roofline and the home’s existing pitch. For low-slope sections common on Florida room additions and ADU flat roofs, we use GAF TPO or GAF Liberty self-adhered systems. For pitched roofs that tie into the original house, we match existing GAF Timberline architectural shingles or step up to GAF Grand Sequoia when wind uplift ratings matter most.
Here’s the compatibility gotcha most homeowners miss: your existing roof may have been installed with one GAF product line, but an addition with a different slope or footprint may require a different GAF system entirely. A 4/12 pitch takes Timberline shingles beautifully. A 1/12 pitch nearly flat section behind an ADU won’t. If someone tells you one product works everywhere, they haven’t looked at your roof. We verify pitch, existing underlayment condition, and the tie-in point where new roof meets old before we write a single material line. We’re an independent contractor, not affiliated with GAF, but we specify their products because the warranties are verifiable and the Miami-Dade wind ratings hold up in our hurricane season.
Styles & brands we work with
Signs Your GAF Home Additions & ADU Is Failing
Most failures on existing additions and ADUs in West Palm Beach show up as symptoms before they become emergencies. Here’s what we see when homeowners call us about an addition that’s causing trouble:
- Water stains on the ceiling where the addition meets the original roofline. The tie-in flashing wasn’t lapped correctly or the original installer used a cheaper sealant that broke down in Florida UV. This is the most common GAF addition failure we repair.
- Mold smell in the ADU after heavy rain. Airflow in a small ADU is tighter than in a house, and a small leak that would dry out in a larger room stays damp. You’re not imagining it. The ceiling cavity is holding moisture.
- Shingle granules collecting in the gutters within the first five years. GAF shingles shouldn’t shed granules that early. If they are, check whether the addition roof was installed over a hot attic with poor ventilation, which cooks shingles from underneath.
- Doors or windows in the addition binding or jamming. A new addition settles, especially on sandy South Florida soil. Some settling is normal. A door that won’t close after two years is not. It usually means the foundation or framing wasn’t sized for our soil conditions.
- Energy bills creeping up every summer since the addition was built. The roofline or the wall insulation is underperforming. In West Palm Beach, that means heat is entering through the attic faster than the AC can remove it.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
A full home addition in West Palm Beach runs $45,000 to $130,000 installed. A detached ADU runs $90,000 to $220,000. Where your project lands inside those ranges depends on four things: square footage, whether you’re on a slab or need pier and beam, the finish level you choose, and what GAF roofing product your roofline needs. A 400-square-foot bedroom bump-out with a matching GAF Timberline roof and builder-grade finishes sits at the low end. A 750-square-foot ADU with a kitchenette, full bath, and standing-seam-style GAF system sits at the top.
Here’s what’s always included in our written price: all labor, all materials named by brand and quantity (GAF underlayment, GAF shingles or membrane, insulation, drywall, paint, trim), permits pulled and inspections passed, drop cloths down, shoe covers at the door, and a photo of the clean-up before the crew leaves. No allowances that quietly balloon. No change orders you discover at the end. We put the number in writing before any work starts, and that’s the number you pay unless you change the scope yourself.
DIY or Call Us?
Home additions and ADUs are not a DIY project. This isn’t a weekend. It’s structural work, electrical work, plumbing, and roofing tied into your existing roofline. Florida building code applies, inspections apply, and a failed roof tie-in during a summer storm can put water inside your walls for weeks before you see it. Graham Stein walks every West Palm Beach job site himself before a single drop cloth goes down, and he still finds surprises behind walls that change the day’s plan. That’s normal. Experience means knowing what to do with the surprise, not hoping it doesn’t happen.
What you can do before calling: check whether the original addition pulled permits (you can request this from Palm Beach County), measure the square footage of the space you want to add, and make a list of what the space needs to do. That preparation makes the first call faster. Then call us at (728) 203-3270 and we’ll bring the answer in writing. Put it in writing, then do exactly that.
FAQs
A properly installed GAF Timberline roof on an addition or ADU in West Palm Beach typically lasts 20 to 30 years with normal Florida sun and storm exposure. GAF’s wind ratings and algae protection matter here, but the tie-in point where new roof meets old roof is the part that fails first if the flashing wasn’t done right. Call (728) 203-3270 if you want us to inspect an existing tie-in before you trust it through another hurricane season.
Yes, a failing tie-in flashing or a small section of damaged GAF shingles on an addition can often be repaired for a few hundred to a couple thousand dollars instead of replacing the whole roof. If the sheathing underneath is rotten from prolonged moisture, we replace that section too. We’ll write the repair in a way that tells you what can wait and what can’t, so you’re not guessing.
A small addition of 300 to 500 square feet typically takes 8 to 14 weeks from permit approval to final inspection, depending on scope and weather. A full ADU runs 4 to 8 months. We give you a firm start and end window in the written scope before the first tool is unpacked, and we call if anything changes. Not voicemail. A person.
We order GAF roofing, underlayment, and accessories directly from our suppliers for every addition and ADU, and we specify exact product lines in the written quote so you can verify warranties yourself. We also work with KraftMaid, Cambria, and Silestone for cabinets and countertops when the addition includes a kitchen or bath. Nothing is drop-shipped to your door; it all arrives on our schedule and goes in on ours.
Written by Graham Stein, Owner, Elmstead Remodeling West Palm Beach at Elmstead Remodeling West Palm Beach, serving West Palm Beach and nearby areas.
