Johns Manville (JM) R-49 Unfaced Fiberglass Batt Insulation 24 in x 48 in, 48 sq ft (U4924)
Regular price $172.57R-49 Unfaced Fiberglass Batt Insulation (24 in x 48 in)
Johns Manville (JM) unfaced fiberglass batt insulation delivers high thermal performance (R-49) for energy-efficient comfort in residential framing cavities. Made with durable, formaldehyde-free bonded glass fibers, it also helps reduce sound transmission for quieter interiors.
Key Features:
- High R-Value Performance: R-49 thermal resistance helps slow heat transfer for improved comfort and efficiency.
- Formaldehyde-Free Fiberglass: Designed to avoid off-gassing formaldehyde in indoor environments.
- Sound Dampening: Helps reduce noise transmission through walls, floors, and ceiling assemblies.
- Durable, Non-Decay Material: Inorganic glass fibers resist rot, mildew, and deterioration and are non-corrosive to pipes and wiring.
- Stable Fit in Cavities: Dimensionally stable batts resist slumping and settling in typical applications.
Please check the Product Data Sheet Here
Specifications Table:
| Specification | Details |
|---|---|
| R-Value | R-49 |
| Insulation Type | Fiberglass batt |
| Facing | Unfaced |
| Width | 24 in |
| Length | 48 in |
| Thickness | 13-1/2 in |
| Coverage Area | 48 sq ft |
| For Use With | Wood stud framing |
| Application | For new construction and remodels; walls, floors, ceilings, basements, attics, and crawlspaces |
| Flame Spread Index | <25 |
| Smoke Developed Index | <50 |
| Temperature Rating | 850 deg F |
| Water Vapor Sorption | <5 % |
| Standards/Certifications | ASTM C665 Type I; ASTM E136; IBC; Energy Star Certified; Greenguard Gold Certified; Indoor Air Quality Certified; NAIMA 16 CFR Part 460; Recycled Content Certified |
| Manufacturer | Johns Manville |
| Manufacturer Part # | U4924 |
| Pieces Per Package | 6 |
Frequently Asked Questions (FAQ):
Q: Is this insulation faced or unfaced?
A: It is unfaced fiberglass batt insulation.
Q: What stud framing is it intended for?
A: It is listed for use with wood stud framing.
Q: Where can it be used in a home?
A: It’s listed for new construction and remodels in walls, floors, ceilings, basements, attics, and crawlspaces.
Q: What are the batt dimensions and thickness?
A: Each batt is 24 in wide x 48 in long and approximately 13-1/2 in thick.
Q: Does it meet common fire/smoke performance criteria?
A: It is listed with flame spread index <25 and smoke developed index <50.
Quiet Luxury, Layered Into the Bones of the Home
Think of this as the invisible couture of a well-designed space—an uncompromising layer that refines comfort without asking for attention. The unfaced fiberglass batt brings a high R-value warmth and a hush that makes rooms feel instantly more intentional. Use it to elevate bedrooms, media rooms, or any wall assembly where serenity is the ultimate finish. It’s the kind of behind-the-scenes essential that makes luxury living feel effortless, every day.
Upgrade your build with JM R-49 unfaced batts for high-performance thermal comfort and quieter rooms.
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