- What wall thickness does R-21 fit?
- It is 5.5 inches thick, which matches a 2x6 stud cavity. In a 2x4 wall it would have to be compressed, which lowers its R-value.
- Which side does the kraft facing go on?
- The facing goes toward the warm, conditioned side of the wall. In cold climates that is the interior; in hot-humid climates the facing direction changes, so check local code.
- How much area does one pack cover?
- The listed coverage is 89.13 square feet. Batts are 23 inches wide and 93 inches long, so plan cuts around studs, outlets and windows.
- Does it need a separate vapor barrier?
- No. The kraft facing is the vapor retarder, so a separate polyethylene sheet is usually not needed and can trap moisture if added.
- Can it be used in ceilings or floors?
- Yes, faced batts work in floors and some ceilings, but in ceilings a vapor barrier is often required on the warm side. Follow local code for your assembly.
- Is it safe for indoor air?
- It carries GreenGuard Gold certification for low emissions. Still wear a mask and eye protection while installing, and seal the facing with tape.
- Where is the Owens Corning R-21 Kraft Faced Fiberglass Insulation Batt 23 in. x 93 in. x 5.5 in. cheapest?
- At Supply Tie, for $139.99, as of our latest check.
- What do buyers say about the Owens Corning R-21 Kraft Faced Fiberglass Insulation Batt 23 in. x 93 in. x 5.5 in.?
- Rated 4.6 out of 5 from 30 ratings.
- Where can I buy the Owens Corning R-21 Kraft Faced Fiberglass Insulation Batt 23 in. x 93 in. x 5.5 in.?
- 6 stores we checked sell it, including Supply Tie, Ace Hardware, Go Build Supply & More, MyHackerTech, S.W. Collins.
