how many bags of ready-mix concrete would

[tommy]

how many bags of ready-mix concrete would cover 2.5 cubic feet at 5 inches deep

[Dirtman]

how many bags of ready-mix concrete would cover 2.5 cubic feet at 5 inches deep

Using Quikrete (available at most building supply stores), each:
80# bag yields approximately 0.60 ft^3 (cubic feet),
60# bag yields approximately 0.45 ft^3,
40# bag yields approximately 0.30 ft^3.

Simply multiply the ft^3 (cubic feet) needed * the yield (listed above), according to the bag size you want or is available.

2.45' * 2.45' * 5" = 2.5 ft^3. Using 80# bags, 2.5 ft^3 * 0.60 ft^3 = 15 bags. As the yields are approximate, I would get 1 bag extra, just in case.

[Guest]

how many bags of ready-mix concrete would cover 2.5 cubic feet at 5 inches deep

Using Quikrete (available at most building supply stores), each:
80# bag yields approximately 0.60 ft^3 (cubic feet),
60# bag yields approximately 0.45 ft^3,
40# bag yields approximately 0.30 ft^3.

Simply multiply the ft^3 (cubic feet) needed * the yield (listed above), according to the bag size you want or is available.

2.45' * 2.45' * 5" = 2.5 ft^3. Using 80# bags, 2.5 ft^3 * 0.60 ft^3 = 15 bags. As the yields are approximate, I would get 1 bag extra, just in case.

Dirtman,

Check your math. I think something went south there. If you need to fill 2.5 ft³, and the bags are 0.6 ft³/bag, you need just over 4 bags, and should round up to 5. You need to divide, not multiply.

[Dirtman]

Way south. It's cold here in Antarctica!

You're absolutely right, you divide . . . not multiply. Thanks for the catch and the correction.

[Guest 2]

How does someone cover 2.5 cubit feet. I assume you mean square feet. I don't have a calculator with me, but 2.5 square feet 5 inches thick is about 1.1 cubit feet. I'm calling it 2 bags.

[Dirtman]

How does someone cover 2.5 cubit feet. I assume you mean square feet. I don't have a calculator with me, but 2.5 square feet 5 inches thick is about 1.1 cubit feet. I'm calling it 2 bags.

It's 6.0025 square feet (2.45' * 2.45').
5" = 5"/12; = 0.41667'

2.45 * 2.45 * 0.41667 = 2.501042 ft^3 (cubic feet), so; 2.5 ft^3 / 0.6 ft^3 per bag = 4.17 bags, rounded up to 5 bags.

George
(Back from the Antarctica)