Best R-49 Attic Insulation Options for Homeowners
For attic projects that call for R-49 fiberglass batts, the Owens Corning R-49 16-by-48-inch and 24-by-48-inch options are the closest matches in this selection. The 16-inch product lists 320 square feet of coverage and 14-inch thickness; the 24-inch option lists 480 square feet. R-38 and R-30 products below are lower-R-value alternatives, not direct substitutes for an R-49 specification. Choose based on required R-value, framing width, coverage, and facing.
| Product | Listed R-Value | Coverage | Best Fit |
|---|---|---|---|
| Owens Corning 16-by-48 R-49 | R-49 | 320 sq. ft. | 16-inch layout; stated 2×12 fit |
| Owens Corning 24-by-48 R-49 | R-49 | 480 sq. ft. | Larger coverage area |
| Owens Corning 16-by-48 R-38 | R-38 | 341.36 sq. ft. | Lower-R-value alternative |
| Owens Corning 24-by-48 R-38 | R-38 | 512 sq. ft. | Higher coverage, lower R-value |
| Johns Manville 24-by-48 R-30 | R-30 | 704 sq. ft. | Large coverage area, lower R-value |
Owens Corning 16-Inch R-49 Fiberglass Batts
This is the clearest match for buyers seeking R-49 attic insulation in a 16-inch-wide batt. The listing gives a 16-by-48-inch size, 14-inch thickness, and a stated fit for 2×12 construction. Ten bags cover 320 square feet, with six batts per bag.
Best for: Attics with a 16-inch layout where the project calls for R-49 and the listed dimensions suit the framing. Its specified R-value and coverage make it easier to plan than products with less detailed dimensions.
Note: The listing recommends maintaining two inches of properly vented air space to help prevent moisture in the insulation. Confirm that the installation can preserve the required ventilation.
Owens Corning 24-Inch R-49 Kraft-Faced Batts
This Owens Corning product is listed as R-49, kraft faced, and 24 by 48 inches. Its ten bags provide 480 square feet of coverage. The listing describes the kraft facing as a moisture barrier used on exterior surfaces.
Best for: Buyers who need R-49 insulation in a 24-inch width and want more listed coverage than the 16-inch R-49 bundle. Check the framing and installation plan before ordering; the supplied features do not specify batt thickness or a framing-depth fit.
Note: Do not assume the product’s dimensions or facing are appropriate for every attic assembly. Verify local requirements and how the facing should be oriented for the specific installation.
Owens Corning 16-Inch R-38 Attic Batts
This kraft-faced fiberglass product is listed at R-38, with 16-by-48-inch batts and 341.36 square feet across eight bags. The listing recommends it for attic use between trusses and identifies the paper backing as a moisture barrier or retardant.
Best for: Shoppers whose project allows R-38 and needs a 16-inch-wide attic batt. It offers more stated coverage than the 320-square-foot R-49 16-inch bundle, but it does not provide the same listed R-value.
Note: Choose this only when R-38 meets the project requirements. The listing also calls for two inches of properly vented air space in its attic guidance.
Owens Corning 24-Inch R-38 Kraft-Faced Insulation
This bundle is listed as R-38 kraft-faced insulation in a 24-by-48-inch size. Eight bags provide 512 square feet, making it a higher-coverage choice than the 16-inch R-38 bundle in this guide.
Best for: Buyers who need a 24-inch-width batt and have a project specification that permits R-38. Its listed coverage helps estimate the number of bundles for a larger area.
Note: This is an R-38 product, not an R-49 equivalent. The provided features do not give batt thickness or specific attic ventilation instructions, so confirm those details before installation.
Johns Manville 24-Inch R-30 Kraft-Faced Batts
This Johns Manville fiberglass option is listed as R-30, kraft faced, and 24 by 48 inches. Eight bags cover 704 square feet. The listed facing is described as a moisture barrier used for exterior surfaces.
Best for: Buyers prioritizing broad coverage in a 24-inch-wide batt when R-30 is acceptable for the application. It is a lower-R-value option than the R-49 products above.
Note: Do not choose it as a replacement for a required R-49 assembly solely because its listed coverage is larger. Confirm the required insulation level for the home and project.
Buying Guide: How To Choose R-49 Attic Insulation
Does the project specifically require R-49?
Check the project plans, local energy requirements, or advice from a qualified building professional. R-38 and R-30 products have lower listed R-values and should be treated as alternatives only when the project permits them. Coverage area does not indicate insulation performance.
Which batt width fits the attic framing?
Compare the product’s stated width with the available space between framing members and the installation layout. The 16-inch R-49 product lists a 2×12 fit and a 14-inch thickness. The 24-inch R-49 listing gives its width but does not state its thickness, so verify fit before buying.
How much insulation should you order?
Measure the area to be insulated and compare it with the stated bundle coverage. The two R-49 choices list 320 and 480 square feet. Allow for the actual layout and installation needs rather than assuming every square foot of a package will match the attic’s dimensions.
Should you choose faced or unfaced batts?
The R-49 products in this guide are listed as kraft faced. Facing affects moisture-control details, so follow the project design and product instructions. Do not add or rely on a vapor-retarding layer without considering the full wall or ceiling assembly and applicable requirements.
Frequently Asked Questions
What does R-49 mean for attic insulation?
R-49 is the listed thermal-resistance value of the insulation product. It is not the coverage area or batt width.
Which product here is specifically listed for a 2×12 attic?
The Owens Corning 16-by-48-inch R-49 product lists a 14-inch thickness and says it is ideal for 2×12 construction.
Can R-38 replace R-49 attic insulation?
Not when the project requires R-49. R-38 has a lower listed R-value; use it only if the project requirements allow it.
How much area does the 16-inch R-49 bundle cover?
The listing states that ten bags cover 320 square feet, with six batts per bag.
Does kraft facing eliminate the need to plan for ventilation?
No. Facing and attic ventilation are separate installation considerations. Follow the product guidance and the requirements for the attic assembly.