Johns Manville (JM) R-38 Unfaced Fiberglass Batt Insulation, 16 in x 48 in, 42.66 sq ft
SKU: 65548730391

Johns Manville (JM) R-38 Unfaced Fiberglass Batt Insulation, 16 in x 48 in, 42.66 sq ft

Sale price$134.24 Regular price$149.16
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Description

Johns Manville (JM) R-38 Unfaced Fiberglass Batt Insulation, 16 in x 48 in, 42.66 sq ftR 38 Unfaced Fiberglass Batt Insulation (16 in x 48 in) JM (Johns Manville) R 38 unfaced fiberglass batts are pre cut for 16 in on center wood framing to help improve thermal performance and add sound control in attics, ceilings, and floors. Unfaced construction has no vapor barrier, making it suitable for adding over existing insulation where permitted. Key Features: High R Value Performance: R 38 fiberglass batts help reduce heat transfer for

R-38 Unfaced Fiberglass Batt Insulation (16 in x 48 in)

JM (Johns Manville) R-38 unfaced fiberglass batts are pre-cut for 16-in on-center wood framing to help improve thermal performance and add sound control in attics, ceilings, and floors. Unfaced construction has no vapor barrier, making it suitable for adding over existing insulation where permitted.


Key Features:

  • High R-Value Performance: R-38 fiberglass batts help reduce heat transfer for improved comfort and energy efficiency.
  • Unfaced for Flexible Use: No vapor barrier, so it can be added to existing insulation where appropriate.
  • Sized for Standard Framing: Pre-cut 48-in length and 16-in width fits 16-in on-center wood framing bays.
  • Sound Control Added: Built-in sound barrier helps reduce noise transmission between spaces.
  • Durable, Moisture-Resistant Material: Won’t rot, mildew, or deteriorate and is noncorrosive to pipes, wiring, and metal components.

Specifications Table:

Specification Details
Brand JM
Category Batt Insulation
Insulation Type Fiberglass
Maximum R-Value R-38
Faced/Unfaced Unfaced
Width (Inches) 16
Length (Inches) 48
Thickness (Inches) 13
Coverage Area (Sq. Feet) 42.66
Sound Barrier Yes
Vapor Retardant No
Formaldehyde Free Yes
ENERGY STAR Certified Yes
GREENGUARD Gold Certified Yes
Framing Type Wood studs
Stud Spacing (Inches) 16
R-Value per Inch 2.923
For Use in Attics Yes
For Use in Ceilings Yes
For Use in Floors Yes
For Use in Walls 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
Fits 2 x 4 Walls No
Fits 2 x 6 Walls No
Will not rot, mildew or deteriorate Yes (as described)
Noncorrosive to pipes, wiring and metal studs Yes (as described)
Package Type Multi-pack
Total Package Quantity 32
Package Count 8
Multi-Pack Quantity 4
Bag Dimensions (L x W x D) 16.5 x 20 x 50
Package Weight (lbs.) 22
Warranty 1-year limited
UNSPSC 11162400

Frequently Asked Questions (FAQ):

Q: Where can I use these batts?
A: Designed for wood-framed attics, ceilings, and floors; not listed for walls, basements, or crawlspaces.


Q: Can I install unfaced insulation over existing insulation?
A: Yes—unfaced batts can be added to existing insulation because they do not include a vapor barrier.


Q: What framing size does it fit?
A: It’s sized for 16-in on-center wood framing and comes in 48-in long batts.


Q: Does it include a vapor retarder?
A: No—this product is unfaced and has no vapor retardant.


Q: Does it help with noise?
A: Yes—this product is listed as having a sound barrier for sound control.


Quiet, cocooning comfort—layered into your home’s architecture

There’s a kind of luxury that isn’t loud—it’s felt in the calm of a perfectly tempered room and the hush that settles over a space. These R-38 unfaced fiberglass batts disappear into the structure, adding warmth, acoustic softness, and an effortless sense of ease overhead in attics and across ceilings and floors. I love the pre-cut, standard-bay sizing—clean lines, minimal fuss, maximum impact. Consider it the invisible foundation for living beautifully: comfort, control, and quiet—always in style.


Upgrade your attic or ceiling with JM R-38 unfaced fiberglass batts for better comfort, quieter spaces, and improved efficiency.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 65548730391

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Jackson Caesar
Alexandria, US
★★★★★ 5
Great investment, and easy to assemble.
Color: Grey
Excellent dividers for the home. I purchased this set 3 years ago and recently had to place another order because the first order proved to be a perfect accessory in my basement apartment. As previously mentioned, I am in a basement apartment, and with these dividers, I can take an open space and create compartments. After a while, you forget that that open space was once a single room. These options added a great deal to my "Fonshuay," and lifestyle. This is a great investment and it was easy to assemble.
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Reviewed in the United States on September 11, 2025
W
Verified Purchase
wlytle
Whiting, US
★★★★★ 1
NO instructions
Color: Grey
there were no instructions with this and it came in 100's of pieces. NOTHING, no picture, kind of hard to assemble when you dont know where to start
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Reviewed in the United States on October 11, 2025
C
Verified Purchase
Cristina Moreta
Bozeman, US
★★★★★ 5
Me cubrió exactamente como esperaba
Color: Grey
Cumplió mis expectativas
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 8, 2026
J
Verified Purchase
JV in Idaho
Chelsea, US
★★★★★ 5
Very nice quality and appearance
Color: Beige
They were surprisingly stout and went together well. We had to return them because when we took them to where they would be used, they were too big to work in that location. Dang. But if we needed them in the future, I wouldn't hesitate to purchase them.
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Reviewed in the United States on October 31, 2025
S
Verified Purchase
shellz
Grantham, US
★★★★★ 3
Poor quality
Color: Grey
Temporary fix, poor quality, get what you pay for.
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Reviewed in the United States on November 22, 2025

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