Owens Corning Home Additions & ADU Nationwide

Owens Corning Home Additions & ADU: The Orlando Owner’s Guide

If you’re planning a home addition or ADU in Orlando and want Owens Corning insulation products specified into the build, plan on $45,000 – $130,000 for the addition itself, with Owens Corning materials running roughly 8 – 12% of your total envelope budget depending on R-value targets and spray foam vs. batt choices. Most Orlando homeowners first realize their current Owens Corning insulation has failed when rooms at the back of the house run 8 – 10 degrees hotter than the front in August, or when the July power bill arrives $140 higher than it did three summers ago. This page covers what we see in Orlando attics and knee walls, what Owens Corning products we specify for additions and ADUs, and what a re-insulation or new-build insulation scope actually costs.

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Key Takeaways:

• Home additions in Orlando run $45,000 – $130,000; ADUs run $90,000 – $220,000; Owens Corning insulation is a $2,800 – $9,000 line item inside those budgets
• Florida humidity degrades fiberglass batts faster than the Owens Corning datasheets suggest, especially in vented attics that hit 140°F
• We stock Owens Corning R-19 and R-30 kraft-faced batts, EcoTouch and Thermafiber on the truck; spray foam is ordered per project
• Penhallow Remodeling Orlando is an independent general contractor, not affiliated with Owens Corning. We install their products because they hold up in Central Florida heat when installed correctly.

Signs Your Owens Corning Home Additions & ADU Is Failing

• Rooms on the west side of your addition run 8 – 10°F hotter than the original house. This usually means the batt insulation in the west wall has settled or was never properly fluffed after installation. Compression at the top 18 inches of each cavity is the classic culprit, especially where the drywall crew pushed batts aside for wiring.
• Your power bill creeps up every July and never comes back down. In Orlando, an under-insulated 400-square-foot addition can add $120 – $180 a month to your cooling load during summer. Compare summer over winter usage. If the gap is widening year over year, the insulation is losing effective R-value.
• You can feel heat radiating through interior walls between the main house and the addition. Interior walls don’t need insulation for thermal reasons in most climates, but in Orlando, a west-facing knee wall inside an attic space absolutely does. If that wall feels warm at 4 p.m., the Thermafiber or batt behind the knee wall has failed or was never installed.
• Condensation stains on ceilings near the HVAC register. This points to a vapor barrier problem, not just a thermal problem. Kraft-faced batts installed with the facing on the wrong side trap moisture in the cavity. In Florida’s humidity, that becomes mold inside 18 months. A new Owens Corning product won’t fix this unless the facing orientation is corrected.
• The attic over the addition is a sauna at 10 a.m. A properly vented and insulated Orlando attic should feel hot but not punishing in the morning. If it’s punishing, your radiant barrier has failed or the attic ventilation was never updated when the addition was framed.

Replacement Cost & What’s Included

For a typical 400 – 600 square foot Orlando home addition, a full Owens Corning insulation scope runs $2,800 – $5,200. For a full ADU built to current Florida energy code, expect $4,500 – $9,000 depending on whether you’re doing spray foam in the roof deck or blown-in fiberglass over batt. The range moves with four things: square footage of conditioned space, whether you want R-19 in walls or double-stud R-30, attic access (a 10/12 pitch roof over a knee wall costs more than a flat truss attic), and whether we’re correcting an old contractor’s mistakes at the same time. Every quote we write includes the cost of materials, labor, disposal of old insulation, and re-sealing penetrations. The number in the written quote is the number on the invoice, and the 365-Day Done Right Promise covers the work in writing. If something fails in the first year because of our installation, we come back and fix it at no charge.

DIY or Call Us?

Insulation isn’t a high-tension part like a garage spring, but it’s not a weekend job either. Fiberglass in an Orlando attic in July is genuinely dangerous work. Attic temperatures hit 140°F, you’re in a respirator and long sleeves, and heat exhaustion sets in faster than most people expect. You can safely do a visual check: pop your head into the attic and look for gaps around can lights, batts that have slumped below the top plate, or pink fiberglass that looks flattened and gray with dust. That tells you what you’re working with.

Where DIY goes wrong: adding new batts over old moldy batts without cleaning the cavity, stapling kraft facing to the wrong side, compressing batts behind wires and plumbing, and skipping air-sealing because it’s tedious. Any one of those mistakes turns a $3,000 insulation job into a $7,000 mold remediation next spring. That’s not scare tactics; I’ve watched it happen on College Park bungalows where a handyman “topped off” the attic in one afternoon. Give you the number first, then pick up the tool. Call (850) 427-6454 and we’ll walk the addition with you, show you what’s in the cavities, and put the fix in writing before anyone touches a batt.

How Much Does It Cost to Add an ADU in Orlando?

Will the Price Change Once the Project Starts?

No. That’s the point of how Penhallow Remodeling Orlando works. You get a written price before any work starts, and the number on day one is the number on the invoice. The only exception is if we open a wall and find something no one could have seen, like a structural issue with the existing framing. In that case, we stop, show you what we found, and write a change order before any additional work happens. No surprise add-ons at the end of the job. If you’re coming from a previous contractor who ballooned the price after demo day, this is the part of working with us that matters most. Call (850) 427-6454 for a written, line-item estimate on your addition or ADU.

Do You Pull the Permits for a Home Addition or ADU in Orlando?

Yes. Penhallow Remodeling Orlando pulls all required permits for home additions and ADU construction, including city of Orlando building permits, electrical, plumbing, and mechanical permits. We also schedule and manage the inspections. Trevor Nash has been through the permitting process on Orlando additions enough times to know which details the inspectors look at first, and that experience keeps the project moving instead of sitting in a review queue. The cost of permits and inspections is included in your written quote, not billed as a surprise line item later.

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