Johns Manville R-38 Unfaced Fiberglass Batt Insulation, 64-sq ft Coverage, 24-in x 48-in, U366S
R-38 Unfaced Fiberglass Attic Batt Insulation, 24x48-in
High R-38, unfaced fiberglass batts designed for wood-framed attics, ceilings, and floors. Precut 24-in x 48-in pieces provide 64 sq ft of coverage per package and install easily between 24-in on-center joists for improved energy efficiency and sound control.
Key Features:
- High Thermal Performance: R-38 batts boost energy efficiency and comfort in attics, ceilings, and floors
- Unfaced Design: No vapor barrier—ideal for adding over existing insulation where permitted
- Precut Convenience: 24-in x 48-in batts sized for 24-in on-center framing; simple press-in installation
- Durable, Healthy Choice: Formaldehyde-free fiberglass that won’t rot, mildew, or corrode pipes/wiring
- Certified for Indoor Air Quality: GREENGUARD Gold and SCS Recycled Content certified; ENERGY STAR partner
Specifications Table:
| Specification | Details |
|---|---|
| R-Value | 38 |
| Coverage Area | 64 sq ft |
| Dimensions (each batt) | 24 in W x 48 in L x 13 in T |
| Stud/Joist Spacing | 24 in on-center |
| Faced/Unfaced | Unfaced |
| Insulation Type | Fiberglass |
| For Use in Attics | Yes |
| For Use in Ceilings | Yes |
| For Use in Floors | Yes |
| For Use in Walls | No |
| Formaldehyde Free | Yes |
| Sound Barrier | Yes |
| Vapor Retardant | No |
| ENERGY STAR Certified | Yes (program partner) |
| GREENGUARD Gold Certified | Yes |
| Framing Type | Wood studs |
| Length | 48 in |
| Width | 24 in |
| Thickness | 13 in |
| Package Weight | 37 lbs |
| R-Value per Inch | 2.923 |
| Package Count | 8 pieces |
| Package Type | Multi-pack |
| Multi-Pack Quantity | 4 |
| Total Package Quantity | 32 |
| Warranty | 1-year limited |
| UNSPSC | 11162400 |
| Bag Dimensions (L x W x D) | 20 x 20 x 50 in |
Frequently Asked Questions (FAQ):
Q: How much area does one package cover?
A: Each package provides 64 square feet of coverage with eight 24-in x 48-in batts.
Q: Can these batts be installed over existing insulation?
A: Yes. Because they are unfaced (no vapor retarder), they can be added over existing insulation where local codes allow.
Q: Where can I use this product?
A: It’s designed for attics, ceilings, and floors with 24-in on-center wood framing; not intended for walls or masonry.
Q: Is the insulation formaldehyde-free?
A: Yes, it is formaldehyde-free and GREENGUARD Gold certified for indoor air quality.
Q: What is the thickness of each batt?
A: Each batt is approximately 13 inches thick to achieve R-38.
Luxurious Warmth, Effortlessly Layered
Imagine a cocooned quiet settling over your home as these plush white batts disappear beneath your attic joists. Their generous 13-inch loft creates a serene, insulated envelope that elevates comfort and hushes the outside world. Pair with crisp, painted ceilings and natural wood finishes to accentuate the calm, controlled environment they enable. This is the invisible foundation of refined, luxurious living—comfort engineered with elegance.
Upgrade your attic with JM R-38 batts today for immediate comfort, quieter rooms, and long-term energy savings.
Original: $98.04
-70%$98.04
$29.41Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
R-38 Unfaced Fiberglass Attic Batt Insulation, 24x48-in
High R-38, unfaced fiberglass batts designed for wood-framed attics, ceilings, and floors. Precut 24-in x 48-in pieces provide 64 sq ft of coverage per package and install easily between 24-in on-center joists for improved energy efficiency and sound control.
Key Features:
- High Thermal Performance: R-38 batts boost energy efficiency and comfort in attics, ceilings, and floors
- Unfaced Design: No vapor barrier—ideal for adding over existing insulation where permitted
- Precut Convenience: 24-in x 48-in batts sized for 24-in on-center framing; simple press-in installation
- Durable, Healthy Choice: Formaldehyde-free fiberglass that won’t rot, mildew, or corrode pipes/wiring
- Certified for Indoor Air Quality: GREENGUARD Gold and SCS Recycled Content certified; ENERGY STAR partner
Specifications Table:
| Specification | Details |
|---|---|
| R-Value | 38 |
| Coverage Area | 64 sq ft |
| Dimensions (each batt) | 24 in W x 48 in L x 13 in T |
| Stud/Joist Spacing | 24 in on-center |
| Faced/Unfaced | Unfaced |
| Insulation Type | Fiberglass |
| For Use in Attics | Yes |
| For Use in Ceilings | Yes |
| For Use in Floors | Yes |
| For Use in Walls | No |
| Formaldehyde Free | Yes |
| Sound Barrier | Yes |
| Vapor Retardant | No |
| ENERGY STAR Certified | Yes (program partner) |
| GREENGUARD Gold Certified | Yes |
| Framing Type | Wood studs |
| Length | 48 in |
| Width | 24 in |
| Thickness | 13 in |
| Package Weight | 37 lbs |
| R-Value per Inch | 2.923 |
| Package Count | 8 pieces |
| Package Type | Multi-pack |
| Multi-Pack Quantity | 4 |
| Total Package Quantity | 32 |
| Warranty | 1-year limited |
| UNSPSC | 11162400 |
| Bag Dimensions (L x W x D) | 20 x 20 x 50 in |
Frequently Asked Questions (FAQ):
Q: How much area does one package cover?
A: Each package provides 64 square feet of coverage with eight 24-in x 48-in batts.
Q: Can these batts be installed over existing insulation?
A: Yes. Because they are unfaced (no vapor retarder), they can be added over existing insulation where local codes allow.
Q: Where can I use this product?
A: It’s designed for attics, ceilings, and floors with 24-in on-center wood framing; not intended for walls or masonry.
Q: Is the insulation formaldehyde-free?
A: Yes, it is formaldehyde-free and GREENGUARD Gold certified for indoor air quality.
Q: What is the thickness of each batt?
A: Each batt is approximately 13 inches thick to achieve R-38.
Luxurious Warmth, Effortlessly Layered
Imagine a cocooned quiet settling over your home as these plush white batts disappear beneath your attic joists. Their generous 13-inch loft creates a serene, insulated envelope that elevates comfort and hushes the outside world. Pair with crisp, painted ceilings and natural wood finishes to accentuate the calm, controlled environment they enable. This is the invisible foundation of refined, luxurious living—comfort engineered with elegance.
Upgrade your attic with JM R-38 batts today for immediate comfort, quieter rooms, and long-term energy savings.
