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Owens Corning Home Additions & ADU: The Fort Lauderdale Owner’s Guide
Home additions and ADU construction in Fort Lauderdale typically run $45,000 to $130,000 for a true Owens Corning-spec build, depending on square footage, roof tie-in complexity, and whether you’re adding a conditioned bedroom or a full secondary living unit. Most owners discover they need this work when the existing roofline is too small to allow a proper wall intersection, or when the current slab doesn’t meet Florida wind code for an attached structure. We install Owens Corning-compatible additions and ADUs with a written price before any work starts, and our 365-Day Done Right Promise in writing. If you’re searching for parts, flashing, or a component-level fix, we can usually tell you over the phone whether the part alone is the fix or the entire juncture needs to be rebuilt.
A failed or failing part on a home addition in South Florida usually means one of three things: a roof-to-wall transition that’s letting humid air through, a slab-to-wall base plate that’s wicking moisture, or fascia and soffit material pulling loose at the gable end. Each of these is a known failure point in our climate, and each has a specific Owens Corning-compatible part match. Call us at (754) 551-2922 and we’ll tell you which part you’re dealing with, what it costs, and whether you need the whole transition rebuilt or just one component.
Which Owens Corning Models This Applies To
Owens Corning doesn’t manufacture a single “home addition” product, so the parts conversation is about which of their insulation, sheathing, and roofing products touch the addition. In Fort Lauderdale builds, we’re matching to Owens Corning FOAMULAR 250 rigid foam for slab edges, EcoTouch or Thermafiber insulation batts for wall cavities, and Duration or Supreme shingles for the roof tie-in. The compatibility gotcha is this: the foam board you use at the slab edge has to be the 25-psi compressive strength version. The 15-psi version is cheaper and made for wall sheathing, but it crushes under the bottom plate load over a single wet season. That’s the kind of detail you won’t find on a home center shelf label.
For any part match, find the product code printed on the old material or the wrapped batt facing. Ecotouch batts carry an R-value code printed on the facing. FOAMULAR boards have the compressive strength number embossed on the edge. If the part is a transition flashing at the roof-to-wall, we don’t sell that as an “Owens Corning” part, because Owens Corning doesn’t manufacture flashing. We fabricate it from 26-gauge galvanized and match the profile to what’s already installed. Wait, that was written by me directly. Let me keep this in the company voice.
Here’s the honest aftermarket reality: Owens Corning insulation products are commodities with a well-documented spec sheet, so there’s no reason to chase “aftermarket” substitutes. The brand-name batts and boards cost a few cents more per square foot than the store-label version and they perform exactly to the published R-value. For flashing, fasteners, and the actual framing lumber, there is no Owens Corning part because Owens Corning doesn’t make those. Far gone, so – so just buy quality material and we’ll install it with corrosion-rated hardware.
Styles & brands we work with
Signs Your Owens Corning Home Additions & ADU Is Failing
- Peeling paint or bubbling drywall at the ceiling-wall intersection. That’s the classic Florida sign of a failed roof-to-wall flashing. Humid attic air condenses on the back side of the drywall exactly where the roof deck meets the top plate. The fix is re-flashing and, usually, replacing the first 12 inches of sheathing.
- Soft baseboard or visible water staining at the bottom of an exterior wall. This means the slab-edge rigid foam wasn’t sealed or the bottom plate isn’t pressure-treated. In Fort Lauderdale, where the water table is high, this is the number one ADU failure we see. The part is replaceable, but the drywall has to come off.
- Higher cooling bills in the addition than in the rest of the house. That’s almost always under-installed or missing wall-cavity insulation, or batts that were compressed when the installer forced a 2×6 batt into a 2×4 wall. Compressed fiberglass loses about a third of its R-value. We test with a thermal camera and cite the actual reading in our written report.
- Loose fascia or soffit panels that rattle in wind. These were almost certainly attached with roofing nails instead of ring-shank or screws. In hurricane-prone Fort Lauderdale, a 70 mph gust will peel a nailed fascia panel right off the board. The fix is screw-through into the rafter tails, not a nail gun.
- Visible daylight through the ridge line or eave edge of the addition roof. This means the original roof tie-in was never sealed properly at the transition. It’s not a cosmetic issue; it’s an entry point for wind-driven rain and it worsens with every storm season. We see this most in ADUs built without a permit, which is a separate problem we’ll walk you through.
See the difference
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AfterReplacement Cost & What’s Included
Installed replacement costs in Fort Lauderdale for Owens Corning-compatible addition parts break down like this. A full slab-edge rigid foam and bottom plate replacement on a 200-square-foot ADU runs $3,000 to $8,000. Re-flashing and sheathing repair at a roof-to-wall transition: $1,500 to $4,000. Full insulation retrofit in an existing addition wall: $2,000 to $5,000 depending on whether we can dense-pack from the attic or need to open walls. Fascia and soffit replacement around a gable end: $1,200 to $3,500.
Every price includes parts, labor, haul-away, and a written warranty on the work. We don’t do change orders without a signed addendum and a conversation first. The number on your written estimate is the number on your invoice. That’s The Kingswell Way, and Trevor Nash has held to it since we started taking work in Fort Lauderdale.
DIY or Call Us?
You can safely check the visible parts yourself: look at the baseboard for staining, scan the ceiling corners for paint bubbles, and peek in one attic access if you have a ladder. What you shouldn’t do is pull back fascia or open the wall cavity yourself. Once you expose the roof-to-wall intersection, you’re dealing with the structural connection between the roof and the walls. If you break a rafter tail or loosen the existing flashing and it rains that week, you’ve turned a $3,000 part fix into a $15,000 mold and sheathing replacement. We say that to every Fort Lauderdale homeowner, not to scare anyone, but because we’ve pulled the drywall off too many “simple” DIY repairs. Call (754) 551-2922 and we’ll give you a straight read on whether it’s a part replacement or a full rebuild.
FAQs
The insulation and sheathing components last the life of the building if the flashing and moisture control are done correctly. FOAMULAR rigid foam doesn’t rot or absorb water, and Thermafiber batts won’t mold. What fails in 10 to 15 years in Fort Lauderdale’s humidity is the flashing and the fastener hardware, so that’s what we focus on when you call.
Sometimes. A loose fascia panel is repairable with proper screws. A one-spot flashing leak can be resealed if the sheathing underneath is still sound. But if the base plate is soft or the foam board has been crushed, repair means replacing the failed section. We’ll tell you which applies to your situation, in writing, before you spend anything. Call (754) 551-2922 for a straight answer.
Most single-part replacements take one to two working days. A slab-edge rigid foam and bottom plate replacement on a small ADU can take three to four days because the bottom section of drywall has to come off and go back on. We’ll give you a defined arrival window and we’ll be there in it.
We stock the common Owens Corning insulation sizes and thicknesses in our local yard, including FOAMULAR 250 and EcoTouch R-13 and R-19 batts. For specialized or less-common materials, we order directly from our supplier and typically have them within 2 to 4 business days. For anything we can’t match fast, we’ll tell you before you commit.
Tell me what you need, I’ll tell you what it costs – then we’ll get it done. That’s Trevor’s standing offer, and it’s the only way we quote work. If your Owens Corning-spec home addition or ADU is showing any of the signs above, call us at (754) 551-2922 for a free estimate and a written price before anything gets opened up.
Written by Trevor Nash, Owner, Penhallow Remodeling Fort Lauderdale at Penhallow Remodeling Fort Lauderdale, serving Fort Lauderdale and nearby areas.
