Owens Corning Attic Insulation Nationwide

Owens Corning Attic Insulation: The San Marcos Owner’s Guide

We stock and install Owens Corning blown-in fiberglass attic insulation in San Marcos homes, with most complete attic jobs running between $1,800 and $3,400 depending on square footage and whether the attic floor needs air sealing first. Same-day installation is available when we have your measurements and attic access details. Homeowners usually notice the problem first through their utility bill - a 30% summer spike is common in San Marcos when insulation has compressed, shifted, or was never thick enough to hit the R-38 the IECC recommends for this climate zone.

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Which Owens Corning Models This Applies To

Owens Corning produces two blown-in fiberglass lines you’ll find in San Marcos attics: ProCat (the professional-grade loose-fill, typically blown to 14-17 inches for R-38) and AttiCat (the retail-blown system sold through home centers, recognizable by its purple bags and the blower machine that comes with rental). The critical compatibility point is base weight: ProCat runs 0.5 pounds per square foot at R-38, while AttiCat needs closer to 0.6 due to slightly different fiber density. We’ve found previous contractors in the Blanco Gardens and Willow Creek areas who mixed the two, creating uneven thermal layers that read right on infrared but leak air at the seams.

To identify what you have, check the stamp on any visible bag remnants or the documentation from your last install. If there’s no paperwork, we measure settled depth and fiber density in three attic locations - the R-value tells you how slow heat moves through the material, the blower-door number tells you whether any of that matters. Topside Attic Insulation San Marcos is an independent service provider, not affiliated with Owens Corning. We also stock Reflectix radiant barrier products for attics where summer radiant heat gain is the dominant load.

Signs Your Owens Corning Attic Insulation Is Failing

• Uneven temperature rooms. The upstairs bedroom runs five to ten degrees hotter in July while the master stays comfortable. This usually means the insulation has been disturbed - trades walking through, storage boxes pushed aside - or was never blown uniformly in the first place.
• Ice dams or heavy icicle lines in winter. Even San Marcos gets freeze events. Warm air escaping through gaps in top-plate sealing melts roof snow; water runs to the cold eave and refreezes. The insulation isn’t the root cause, but it’s where the symptom shows.
• Insulation visible below joist tops. Settled blown-in should still cover the full depth of your ceiling joists. If you can see wood, you’ve lost 20-30% of your original R-value to gravity and vibration from the HVAC air handler.
• Rodent trails or nesting material. Fiberglass doesn’t rot, but rodents compress it into highways. We see this most in older San Marcos slab homes near the Texas State University corridor where roof vents were never properly screened.
• Your July electric bill exceeds $280 for a home under 2,200 square feet. At current CPS Energy rates, that’s the threshold where attic performance is usually the culprit, not the HVAC unit itself.

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After

Replacement Cost & What’s Included

Most Owens Corning attic insulation jobs in San Marcos run $1,800-$2,600 for homes under 1,800 square feet, and $2,600-$3,400 for homes between 1,800 and 3,200 square feet. The lower end assumes your existing insulation can stay and we add a new cap layer; the higher end includes removal of contaminated or water-damaged material, plus full air sealing of top plates, can lights, and plumbing penetrations before any new fiber goes in.

Every job closes with a Documented Photo Record and, when applicable, before-and-after blower-door numbers. Under Haven Standard Clause 1, you get a written price before any work starts - flat, not time-and-materials - plus a written scope and written warranty. The 365-Day Done Right Promise covers all completed work. We source Owens Corning, Johns Manville, Knauf, Rockwool, CertainTeed, Icynene, Demilec, and GreenFiber materials - no proprietary lock-in, so we match the product to your attic’s actual condition.

DIY or Call Us?

You can safely check your attic’s settled depth with a tape measure and a flashlight - look for the ruler markers we leave on trusses, or measure from the drywall to the top of the fiber in three spots. You can also photograph any bag labels or visible damage for us to review by text.

What you shouldn’t do: rent a blower and add new fiber over an unsealed attic floor. The air leaks remain, the new insulation masks them, and your summer bill barely moves. We’ve pulled back year-old DIY jobs in San Marcos where the homeowner spent $800 on material and saw no measurable change. The blower-door test - a pressurization reading that shows, in one number, how much air your building envelope is losing - is what separates guesswork from performance. Wes Okafor has been running these tests since his Dawson Technical Institute training, and we won’t blow insulation until the sealing is documented. Call (737) 337-8049 and we’ll read your attic with you, no charge.

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