I posted here a while back regarding R50 or 60 being too heavy for 5/8 sheetrock ceiling 2’O.C. Thanks for the thoughtful replies.
In calling the 5 lumber yards in our area for bids on the material I got 5 very different answers of actual total weight. Since the rating for this sheetrock is 2.2 lbs. sq’, and the ceiling is 1000 sq.’ I obviously don’t want over 2,200 lbs. However, for R50 total weight quoted went from 1518 lbs. to 2730 lbs!
My questions are: do brands of cell. vary that much in loft?
One brand (cocoon) brags sit is ‘low dust’, it also was lowest total weight quoted : could the others have so much dust they weigh a lot more?
thanks, Dale
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all good cellulose mfrs comply with certain standards
google on ASTM C 739
the bales we buy are 26.5 lb.
the settled density is stated at 1.4 lb/cf and the sidewall density is 2.2 lb/cf
that's for a 100% Boric Acid & Borax product, which costs a little more than the more common Aluminum Sulfate based product
every mfr should publish a net coverage chart for open blow & sidewall
the same mfr also produces an aluminum sulfate based product.. same weight for the open blow, but i notice the sidewall density is 2.7 lb/cf.. i have no idea why
i'm paying $7.50 /bale for the Borax product, but i could buy the aluminum sulfate product for $6.75