What You'll Learn
Common Mistakes With Batts
Loose batts
Often the problem is sloppy framing. "If the studs are 16.5 inches on center and you're using batts made for 16 inches, you'll have a crack on each side that air can move through," says Tom. In this case, it's best to use cavity-filling foam or blown-in insulation.
Compressed fiberglass batts
Fiberglass insulation gets its R-value from the amount of air it traps between its fibers. If it's jammed too tightly into a cavity, it can't trap as much air and won't be as effective.
Doubled vapor barriers in attic
Laying a second layer of fiberglass batts in the attic is an easy way to boost R-values. But if the new layer has a kraft-paper backing, it can trap moisture and turn the layers underneath into a soggy mess. "I see this mistake all the time," Tom says.
Loose batts
Often the problem is sloppy framing. "If the studs are 16.5 inches on center and you're using batts made for 16 inches, you'll have a crack on each side that air can move through," says Tom. In this case, it's best to use cavity-filling foam or blown-in insulation.
Compressed fiberglass batts
Fiberglass insulation gets its R-value from the amount of air it traps between its fibers. If it's jammed too tightly into a cavity, it can't trap as much air and won't be as effective.
Doubled vapor barriers in attic
Laying a second layer of fiberglass batts in the attic is an easy way to boost R-values. But if the new layer has a kraft-paper backing, it can trap moisture and turn the layers underneath into a soggy mess. "I see this mistake all the time," Tom says.
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