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Knauf EcoBatt R-11 / R-13 Unfaced Fiberglass Batt Insulation 3-1/2 in.
Regular price $73.39Orders start at $399 — combine any items to reach the minimum. Learn more
Knauf EcoBatt R-11 / R-13 Unfaced Fiberglass Batt Insulation 3-1/2 in.
Knauf EcoBatt unfaced fiberglass batts in 3-1/2 in. thickness fit 2x4 walls and are offered as R-11 and R-13 in 16 in. and 24 in. widths. Batts are 96 in. long and sold by the bag with stated coverage per bag. Pair with a vapor retarder where the assembly calls for one, since these batts are unfaced.
Key Features:
- R-11 and R-13 options: Choose R-11 or R-13 thermal performance in the same 3-1/2 in. thickness.
- Fits 2x4 walls: 3-1/2 in. batt thickness matches standard 2x4 stud cavity depth.
- 16 or 24 in. widths: Available in 16 in. and 24 in. widths to match common framing spacing.
- Unfaced batts: Unfaced brown fiberglass batts for use where a separate vapor retarder is specified.
- Bag coverage stated: Bags are listed with coverage from 128 to 176 sq. ft. depending on the variant.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Knauf Insulation |
| Sell unit | 1 bag of batts, coverage as listed |
| Product line | Knauf EcoBatt Unfaced Insulation |
| Available sizes | R-11 3-1/2 in. x 16 in. x 96 in. (170.67 SF/bag); R-13 3-1/2 in. x 16 in. x 96 in. (128 SF/bag); R-13 3-1/2 in. x 24 in. x 96 in. (176 SF/bag) |
| Material | Fiberglass |
| Color / finish | Brown (EcoBatt color) |
| Thickness | 3-1/2 in. |
| Width | 16 in. or 24 in. |
| Length | 96 in. |
| R-value | R-11 or R-13 as listed |
| Coverage per unit | 128.00, 170.67 or 176.00 sq. ft. per bag depending on variant |
| Facing | Unfaced |
| Intended use | Thermal insulation for framed wall cavities |
Coverage & How Much You Need:
One bag covers between 128 and 176 sq. ft. depending on the variant: R-11 16 in. covers 170.67 sq. ft., R-13 16 in. covers 128 sq. ft., and R-13 24 in. covers 176 sq. ft. Divide your wall area by the bag coverage and round up.
Fit and Compatibility:
Fits 2x4 stud cavities at 16 in. or 24 in. on center; pair with a separate vapor retarder or faced product if the code or design requires one. Fastening or friction fitting depends on the framing details.
Frequently Asked Questions (FAQ):
Q: What R-values and widths are offered?
A: R-11 in 16 in. width and R-13 in 16 in. or 24 in. width, all 3-1/2 in. thick and 96 in. long.
Q: How many bags do I need?
A: Divide your wall area by the bag coverage: 170.67 sq. ft. for R-11 16 in., 128 sq. ft. for R-13 16 in., or 176 sq. ft. for R-13 24 in.
Q: Are the batts faced?
A: No, these EcoBatt batts are unfaced; add a separate vapor retarder if your assembly requires one.
Q: Will they fit 2x4 walls?
A: Yes, the 3-1/2 in. thickness is designed for 2x4 stud cavities.
Q: How are they installed?
A: Press batts friction-fit into the cavity so they fill the depth without compressing, and cut around wiring and boxes with a sharp knife.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Pick R-13 when the wall spec calls for it; R-11 can suit applications with lower R requirements at the same thickness. Match batt width to framing: 16 in. batts at 16 in. on center and 24 in. batts at 24 in. on center, so edges fill the cavity without bunching. Because these are unfaced, plan vapor control with poly or a smart membrane where required.
Wear gloves, long sleeves, eye protection and a dust mask when handling fiberglass batts to avoid skin and respiratory irritation.
Order Knauf EcoBatt unfaced R-11 and R-13 batts for your 2x4 wall insulation package.
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