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Owens Corning Home Additions & ADU: The Miami Owner’s Guide
Adding square footage to a Miami home with Owens Corning materials typically runs $53,100 to $153,400 installed, depending on whether you’re building out, building up, or converting a garage into an ADU. We stock Owens Corning insulation and related envelope components at Sawyer Remodel Miami, and we can match what’s already in your walls so the new section performs the same as the original build. Most owners discover they need Owens Corning-compatible materials when a home addition starts feeling hotter than the rest of the house, or when an older ADU’s insulation has compressed into something closer to cardboard than insulation.
Before we get into pricing and compatibility, one honest note: this is not a small-dollar decision, and the number above is the honest range for Miami. We put the price in writing before work starts, and the invoice matches that number. Always has. Always will.
Which Owens Corning Models This Applies To
Owens Corning doesn’t make “home addition” kits. What they make are the building envelope products that go inside the addition: insulation, air sealing products, and roofing underlayment. If your existing home was insulated with Owens Corning, the most important thing is matching the product line so the new space performs the same way. In Miami, that usually means one of three products: Owens Corning EcoTouch fiberglass batts, Owens Corning PROPINK blown-in fiberglass, or Owens Corning FOAMULAR rigid board for exterior sheathing.
Here’s the compatibility gotcha that trips up a lot of Miami homeowners: the R-value printed on the batts in your attic is the assembly R-value under ideal conditions, not what you get after humidity and heat cycling. We’ve pulled out R-30 batts in Coral Gables homes that were testing closer to R-18 after ten years of South Florida humidity. If you’re matching an addition to existing insulation, we check the actual condition, not just the label. For OEM versus aftermarket: Owens Corning is the OEM for all three product families, and for insulation specifically there’s no meaningful aftermarket equivalent. You can buy generic fiberglass, but the blown-in coverage per bag and the batt width consistency are not the same. We buy Owens Corning direct or through named distributors, not from whatever pallet showed up at a big-box store.
One more thing worth knowing: Owens Corning changed their batt sizing years ago to accommodate 2×6 framing with better friction-fit, and older Miami homes framed with true 2x4s can create a sloppy fit if you order the wrong width. We measure the actual cavity, not the framing label.
Styles & brands we work with
Signs Your Owens Corning Home Additions & ADU Is Failing
- Hot spots in the new space. You can feel the temperature change when you walk from the original house into the addition. The insulation was either installed with gaps, compressed during install, or it’s the wrong R-value for that wall cavity.
- Humidity swings and condensation. If the windows in the addition fog or sweat more than the rest of the house, the vapor barrier or air sealing wasn’t right. In Miami humidity, this isn’t a comfort issue, it’s a mold invitation.
- Energy bills that climbed after the build. Older additions done cheaply often skipped the air sealing step entirely. Insulation without air sealing is like wearing a jacket in the wind. The heat finds the gaps.
- Signs of pest intrusion in the addition. Gaps where the addition meets the original structure let rodents and insects in. Owens Corning products don’t create the problem, but a poorly sealed envelope makes it worse.
- Settled or sunken batts. If you can see a gap between the top of the wall insulation and the wall plate, gravity and time have pulled the batts down. It happens sooner in humid Miami air that degrades the friction fit.
See the difference
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AfterReplacement Cost & What’s Included
For a home addition or ADU in Miami, plan on $53,100 to $153,400 installed, with the spread driven mostly by size, structural complexity, and finish level. A garage conversion to ADU lands between $35,400 and $94,400. A full standalone ADU runs $106,200 to $259,600. Those are not low-ball teaser numbers. They’re what real Miami jobs cost when the work is permitted, inspected, and done with materials that hold up to humidity.
What’s included in our number: the Owens Corning insulation and air sealing products matched to your existing home, framing, drywall, electrical, plumbing rough-in, fixtures, and finish work. Every line item is on a written estimate before we start. If the scope changes, you approve the change before we do it. Our 365-Day Done Right Promise means if something isn’t done right in that first year, we come back and make it right. No argument, no chasing.
DIY or Call Us?
You can safely check your addition’s insulation by pulling a switch plate cover and looking for batts or blown-in material behind the box. You can check attic insulation depth with a tape measure. What you shouldn’t do is try to remove or reinstall insulation in a Miami attic in August without the right gear. Fiberglass in the skin, in the lungs, in the eyes while you’re sweating at 2 p.m. is a miserable way to spend a Saturday, and it won’t fix whatever caused the failure in the first place.
Structural changes, electrical, plumbing, anything tied to an ADU conversion. That’s a licensed contractor’s work. If your addition isn’t holding temperature, the fix usually requires opening a wall or two to find where the envelope failed. We do that with a written price in your hand before the first tool comes out. Call (850) 801-8046 and we’ll schedule a free estimate.
FAQs
Fiberglass insulation itself doesn’t expire, but in Miami’s humidity and heat, the installed performance degrades in 15 to 25 years, especially if air sealing was skipped. The material doesn’t rot, but it settles, absorbs moisture, and loses R-value. If your addition is 10-plus years old and feels warmer than the original house, the insulation is worth checking.
Sometimes, yes. If the batts have settled in one wall cavity, we can re-support them and add air sealing without a full tear-out. But if the insulation is compressed, moisture-soaked, or full of pest damage, replacement is the honest answer. We’ll tell you which one your job needs and show you why. Call (850) 801-8046 for an exact quote, and the estimate is free.
Garage conversions typically run 10 to 16 weeks. Ground-up ADUs run 4 to 8 months, depending on permitting and weather. Home additions fall between those. Miami’s permit review adds time every builder has to live with. We give you a written timeline before we start and photo updates as the job progresses, so you’re not wondering what happened this week.
Yes. We keep Owens Corning EcoTouch batts, PROPINK blown-in, and FOAMULAR rigid board in our Miami inventory, along with the air sealing products that go with them. We also stock KraftMaid cabinetry, Cambria and Silestone countertops for finish work. If your job needs a specific Owens Corning product we don’t have on the shelf, we order it and it’s line-itemed on your estimate before work starts.
Good work doesn’t need a sales pitch. It needs a clear price, a clear scope, and a crew that shows up. If you’re planning an addition or an ADU in Miami and want Owens Corning materials done right the first time, call (850) 801-8046 and talk to us about your project. The estimate is free, the price lands in writing, and Luca Romano and the Sawyer Remodel Miami crew will be the ones doing the work.
Written by Luca Romano, Owner & Lead Contractor, Sawyer Remodel Miami at Sawyer Remodel Miami, serving Miami and nearby areas.
