Question 1

How many bags of concrete do I need for a slab?

Accepted Answer

It depends on the slab dimensions. A 60lb bag yields about 0.45 cubic feet and an 80lb bag yields about 0.6 cubic feet. For a 10x10 foot slab that is 4 inches thick, you need about 1.23 cubic yards, or roughly 56 bags of 80lb concrete.

Question 2

What is the difference between cubic feet and cubic yards?

Accepted Answer

One cubic yard equals 27 cubic feet (3ft x 3ft x 3ft). Concrete is typically sold and delivered in cubic yards. For smaller projects, pre-mixed bags (60lb or 80lb) are more practical.

Question 3

Should I add extra concrete for waste?

Accepted Answer

Yes, it is recommended to order 5-10% more concrete than calculated to account for spillage, uneven surfaces, and slight measurement variations. Our calculator shows the exact amount needed; consider rounding up.

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