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.