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Community and Q&A

Dense Pack Coverage?

PatriciaCranberry | Posted in General Questions on

My installer used a brand of cellulose that doesn’t have a coverage chart for dense pack cellulose. But if I know my total square footage and depth, can’t I estimate this myself?

Example: 36 x 60 x 13.5 tall space with 2×6 walls (5.5 inches or 0.458 feet deep) less 492 square feet of garage doors and doors and windows=961 cubic feet (includes the 16″ o.c. framing) (maybe a total of 9 linear feet of wood framing space overall) so adjust that cubic feet down to 900 cubic feet. At 3.5 lbs per square foot shouldn’t I expect that the insulation required to fill the walls would be 900 cubic feet x 3.5 lbs per cubic feet=3150 pounds/28 pounds per bag: 113 bags?

What about a ceiling area of 24″ on center 11/7/8 I-joist. Lets assume no deduction for the webbing and the flanges…just assume 2096 cubic feet of ceiling. That would mean 2096 cubic feet x 3.5 lbs per cubic foot= 7336 pounds/28 pounds per bag: 262 bags?

Can this be a reasonable expectation for bag usage?

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  1. GBA Editor
    Martin Holladay | | #1

    I didn't check your multiplication, but you have the concept right.

    For dense-packed bays, you are aiming for 3.5 pounds per cubic foot.

    You multiply the number of cubic feet by 3.5 to get the total weight of cellulose needed.

  2. PatriciaCranberry | | #2

    I did a deeper dive based on the dimensions of the I-joist volume. It makes quite a difference when you remove that cubic feet volume.

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