Johns Manville R-38 Attic Unfaced Fiberglass Batt Insulation, 63.33-sq ft Coverage (23.75-in W x 48-in L) - U1348SR 38 Unfaced Fiberglass Batt Insulation for Attics Formaledehyde free fiberglass batts deliver R 38 thermal performance for attics and cathedral ceilings. Pre cut 48 in lengths fit 24 in on center framing and provide 63. 33 sq ft of coverage per pack. Key Features: High R Value Performance: R 38 insulation boosts energy efficiency and comfort Unfaced Design: No vapor barrierideal for adding over existing insulation Pre Cut Convenience: 48 in batts

R-38 Unfaced Fiberglass Batt Insulation for Attics

Formaledehyde-free fiberglass batts deliver R-38 thermal performance for attics and cathedral ceilings. Pre-cut 48-in lengths fit 24-in on-center framing and provide 63.33 sq ft of coverage per pack.

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Key Features:

• High R-Value Performance: R-38 insulation boosts energy efficiency and comfort
• Unfaced Design: No vapor barrier—ideal for adding over existing insulation
• Pre-Cut Convenience: 48-in batts sized for 23.75-in width cavities with 24-in stud spacing
• Durable Fiberglass: Will not rot, mildew, or corrode pipes, wiring, or metal studs
• Low Emissions Certifications: GREENGUARD Gold and SCS Recycled Content certified

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Specifications Table:

Specification	Details
Coverage Area (Sq. Feet)	63.33
Length (Inches)	48
Width (Inches)	23.75
Thickness (Inches)	12
Faced/Unfaced	Unfaced
Framing Type	Wood studs
Insulation Type	Fiberglass
Maximum R-Value	38
R-Value per Inch	3.1667
Stud Spacing (Inches)	24
For Use in Attics	Yes
For Use in Ceilings	Yes
For Use in Walls	No
For Use in Floors	No
For Use in Basements	No
For Use in Crawlspaces	No
For Use in Doors	No
For Use in Duct	No
For Use in Electrical	No
For Use in Garage Doors	No
For Use in Masonry	No
For Use in Plumbing	No
For Use in Vents	No
For Use in Windows	No
Formaldehyde Free	Yes
Sound Barrier	Yes
Vapor Retardant	No
ENERGY STAR Certified	Yes
GREENGUARD Gold Certified	Yes
Warranty	1-year limited
Bag Dimensions (L x W x D)	24.3 x 20 x 50
Package Weight (lbs.)	45.68
Package Type	Multi-pack
Package Count	8
Multi-Pack Quantity	4
Total Package Quantity	32
UNSPSC	11162400

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Frequently Asked Questions (FAQ):

Q: How much area does one pack cover?
A: Each pack provides 63.33 square feet of coverage.

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Q: Can I install this over existing insulation?
A: Yes, the unfaced batts can be laid over existing attic insulation where a vapor barrier is not needed.

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Q: What framing spacing is this sized for?
A: These batts are designed for 24-in on-center framing with a 23.75-in cavity width.

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Q: Is the product formaldehyde-free?
A: Yes, it is formaldehyde-free and GREENGUARD Gold certified for indoor air quality.

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Q: Where can it be used?
A: Primarily for attics and cathedral ceilings; not intended for walls or crawlspaces.

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Quiet, Cozy Attics with Effortless Elegance

This R-38 batt brings a serene hush and steady comfort to upper levels, wrapping your home in a clean, minimalist layer. The slim profile is tailored for cathedral ceilings, creating a refined envelope without bulk. Pair it with soft, natural finishes—think pale woods and matte paints—to amplify its calm energy efficiency. Consider it a foundational luxury: invisible, indispensable, and beautifully effective.

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Upgrade your attic with R-38 performance and start saving on energy costs today.