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Owens Corning Home Additions & ADU: The Austin Owner’s Guide
Owens Corning home additions and ADU projects in Austin typically run $45,000 to $130,000 for a full addition, and $90,000 to $220,000 for a detached ADU. That’s the installed range we quote most often, and it includes plans, permits, materials, labor, and finish work. Most Austin homeowners call us because their existing addition or ADU has a failing roof system, compromised insulation, or water intrusion at the transition point where the addition ties into the original house – and they want someone who knows Owens Corning products well enough to match them correctly.
We’re an independent Austin contractor, not affiliated with Owens Corning, but we’ve built enough additions and ADUs with their roofing, insulation, and sheathing systems to know exactly what works in this climate and what doesn’t.
Which Owens Corning Products This Applies To
If your Austin home addition or ADU was built with Owens Corning materials, the components that matter most are the roofing shingles, the insulation system, and the structural sheathing. Owens Corning makes several shingle lines we see regularly on Austin additions: Duration, Oakridge, and the more budget-conscious Supreme line. Duration is the one we recommend for additions and ADUs because its SureNail strip holds up better in the high-wind thunderstorms that roll through central Texas from March through June.
The compatibility gotcha most Austin homeowners miss: Owens Corning Duration shingles need to be installed over properly vented roof decking, and many older additions in neighborhoods like Mueller, Hyde Park, and Brentwood were originally built with cheap decking that’s now warped in the Texas heat. When we open up a failing addition roof, the shingles are rarely the root problem – it’s the decking and ridge ventilation underneath. If your addition is more than 12 years old and you’re seeing granule loss in your gutters, that’s usually the sign that the Owens Corning shingles have been baking in Austin’s 100-degree summers without adequate airflow. The fix is not always a full re-roof. Sometimes it’s adding ridge vents and replacing the decking in sections, then re-shingling with the correct Owens Corning product.
For insulation, Owens Corning PINK Fiberglas batts and AttiCat blown-in systems are what we install most often in ADUs. In Austin, the spec that matters is R-38 or better in the ceiling, which is what the city’s energy code requires for new ADU construction. If your ADU was permitted after 2017, it should already meet that. If it’s older, it probably doesn’t, and that’s why your ADU is 15 degrees hotter than the main house every August.
Homeowners should also know: Owens Corning manufactures their own line of sheathing and underlayment products. If your addition has a leak at the roof-to-wall transition, the underlayment is usually where the failure starts. That’s especially true on Austin ADUs with low-slope or flat roof sections, where standing water after a July downpour can sit for 48 hours. We specify Owens Corning WeatherLock self-sealing underlayment on any addition or ADU with a slope under 3:12, because the standard felt underlayment won’t survive that kind of pooling.
Styles & brands we work with
Signs Your Owens Corning Home Addition or ADU Is Failing
- Granule loss in the gutters. If you’re cleaning dark, sand-like granules out of your addition’s gutters after every wind event, the Owens Corning shingles are past their mid-life point. Austin’s UV index accelerates granule breakdown, especially on south-facing roof planes.
- Water staining at the ceiling-to-wall corner. This is the classic sign of a failed transition flashing where the addition ties into the original roofline. The flashing wasn’t tied into the Owens Corning underlayment properly during the original build, and Austin’s wind-driven rain has been working its way in ever since.
- Rooms in the addition run 8 to 12 degrees hotter than the rest of the house. That’s an insulation or ventilation failure. In Austin, this shows up most obviously in July and August, when a properly insulated ADU should stay within 4 degrees of the main house’s temperature.
- Bubbling or warping on the addition roof deck. If you can see visible humps from the ground, moisture has been trapped in the decking. Owens Corning shingles can’t seal correctly over a warped deck, so the problem compounds quickly.
- Higher energy bills that track with the addition’s square footage. If your electricity usage shot up after the addition or ADU went in, and it hasn’t settled, the Owens Corning insulation was either installed with gaps or the wrong R-value for an Austin-code build.
See the difference
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AfterReplacement Cost & What’s Included
Here are the installed price ranges we quote for Austin home addition and ADU work:
- Full home addition: $45,000 – $130,000
- Detached ADU construction: $90,000 – $220,000
- Garage conversion: $30,000 – $80,000
- Roof replacement on an existing addition: $8,000 – $20,000
- Insulation retrofit on an existing ADU: $2,000 – $6,500
What drives the range on a full addition is the foundation type, the finish level, and whether the existing house’s HVAC can be extended or needs a separate mini-split system. On ADUs, the biggest variable in Austin is site access. A backyard ADU on a lot with a 40-foot side yard is a much simpler build than one that needs a crane to set roof trusses over the main house.
Every project gets a written price before work starts. That’s not a maybe – it’s how we’ve operated since 2004 as part of the Threshold Group family of home-service companies. You’ll see the line items, the Owen Corning product specs, and the labor costs. If something changes during construction, we discuss it with you before it goes on the bill. No change orders appear from nowhere.
Our workmanship warranty is stated plainly: 365 days from the completion date. If anything we installed is not right within that year, we come back and make it right at no cost. That’s the 365-Day Done Right Promise, and it covers the labor and the materials we supplied. Owens Corning products also carry their own manufacturer warranties, which we’ll walk you through when you make your material selections.
DIY or Call Us?
For Owens Corning home additions and ADUs in Austin, there’s no honest DIY version of this work. Structural additions, ADU construction, and roof tie-ins involve load-bearing framing, electrical rough-in, plumbing, and roofing that requires a licensed contractor to pull permits in the city of Austin. Doing this work without permits will surface when you try to sell the house, and Austin’s code enforcement division does follow up on unpermitted addition complaints.
What an Austin homeowner can do is keep an eye on the existing addition’s roof and insulation: check the gutters for granules after spring storms, look for ceiling stains where the addition meets the house, and track your energy bills month to month. If you spot one of the failure signs above, call us at (903) 623-1966 and describe what you’re seeing. Tell me what’s wrong with it. We’ll figure out what it actually needs. That call is free, and so is the estimate that follows.
FAQs
Owens Corning Duration shingles typically last 15 to 20 years on an Austin addition, compared to the 25 to 30 year rating listed by the manufacturer. The constant UV exposure and hail events in central Texas take about 25 percent off the top. Proper attic ventilation is the single biggest factor in whether you hit the higher or lower end of that range.
Yes, if the shingles are under 10 years old and the damage is isolated to one slope or a few wind-damaged rows, a targeted repair usually makes sense. In Austin, the decision point is whether the decking underneath is still sound. If it’s not, repairing shingles over bad decking just delays the inevitable by a year or two. Call (903) 623-1966 and we’ll tell you which situation you’re in after a roof inspection.
A full home addition typically takes 4 to 8 months from permit to final inspection, and a detached ADU runs 6 to 12 months. Austin’s permitting queue is the biggest variable – the city’s residential review can add 4 to 8 weeks at the front end. We pull permits for every project as part of our contract.
We stock the common Owens Corning items – Duration shingles in the Austin-popular colors, WeatherLock underlayment, R-38 PINK Fiberglas batts, and AttiCat blown-in insulation – and we order the less common sizes per project. For ADU builds, we also work with KraftMaid, Cambria, and Silestone for interior finishes, so you can make all your material selections in one conversation with our team.
Written by Isaac Pruett, Owner, Mason Remodeling Co Austin at Mason Remodeling Co Austin, serving Austin and nearby areas.
