How Many Bags Of 80 Pound Quikrete Do I Need For 9 Sonotubes 8" Dia. X 24" High?


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Larry Patterson answered
NUMBER 1:  Check an actual bag and see how many cubic feet it is supposed to cover.  I have looked at many sites on web and got several answers.  Most frequent was 2/3 of a cubic foot per 80 pound bag, or say 0.67 cf per 80 lb bag.
**The 0.67' below is not related to one above.  This 0.67' is 8" converted to feet!
Area = 0.67'/ 2   Square the  result x 3.14 = Area in square feet
Area in sq ft x 2.0' (depth)=  one sonotube volume in cubic ft
one sonotube volume  x   9  =  cu ft all sonotubes
I get  9.47 bags, say 10 bags plus one for waste.
But you have to check my math and check on what they claim a bag will do in volume.  Usually the big box stores will let you return unopened bags.  don't run short- very frustrating in the middle of pouring.

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