Which is better for a 2x4 wall?

The Knauf roll. Its 3.5 in thickness fits a 2x4 cavity, while the Owens Corning roll is 6.25 in thick and needs a deeper cavity.

Which gives more R-value per roll?

The Owens Corning roll at R-19. The Knauf roll is R-11, so you would need nearly two layers to match it.

Which covers more square footage?

The Knauf pack at 88.13 sq ft versus 48.96 sq ft for the Owens Corning roll. You need about two Owens Corning rolls to cover the same area.

Is the Knauf roll worth the extra cost?

At its low of $18.98 on 2026-11-02 it is the cheaper way to cover a wall at R-11. At its high of $54.99 on 2026-10-31 it costs more per square foot than the Owens Corning roll.

Which is better for an attic?

The Owens Corning roll. Attics usually want R-19 or higher, and the Knauf roll tops out at R-11.

Does either come with a vapor retarder?

Both have Kraft facing. Owens Corning lists a permeance of 1.0 for its Kraft facing; Knauf does not list a permeance figure.

Owens Corning R-19 Kraft Faced Insulation Roll vs Knauf R-11 Kraft-Faced Fiberglass Insulation

Buy the Owens Corning roll if you need R-19 in a 15-inch width for 2x4 walls or attics; buy the Knauf roll if you want the cheapest coverage for a low-R-value wall job. The Knauf pack covers 88.13 sq ft at R-11, while the Owens Corning roll covers 48.96 sq ft at R-19, so you need roughly two Owens Corning rolls to match one Knauf pack's area. The Knauf price has swung from $54.99 on 2026-10-31 to $18.98 on 2026-11-02, so check the current price before you buy.

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