CostBuildrHow Much Cement for a 10×10 Slab
Whether you're building a small patio, a shed base, or a utility slab, knowing the exact cement quantity for a 10×10 ft slab prevents waste and shortages. This guide walks through the calculation step by step using the standard 1:2:4 concrete mix ratio.
Step-by-Step Volume Calculation
A 10×10 ft slab that is 4 inches (0.33 ft) thick has a wet volume of 10 × 10 × 0.33 = 33 cubic feet. If you're using a 5-inch slab (common for residential), the volume becomes 10 × 10 × 0.417 = 41.7 cft. Always add 5–10% extra to account for spillage, uneven ground, and formwork absorption, so plan for approximately 35–46 cft of wet concrete.
Concrete shrinks when mixed, so dry ingredients occupy about 1.54 times the wet volume. For the 4-inch slab: 33 × 1.54 = 50.8 cft of dry material total. For a 5-inch slab: 41.7 × 1.54 = 64.2 cft. This dry volume is then split among cement, sand, and crush according to the mix ratio.
Splitting by 1:2:4 Ratio
In a 1:2:4 ratio, the total parts are 1 + 2 + 4 = 7. For the 4-inch slab (50.8 cft dry): cement = 50.8 / 7 = 7.26 cft. Since one 50 kg bag of cement = 1.25 cft, you need 7.26 / 1.25 ≈ 5.8 bags—buy 6 bags. Sand = 50.8 × 2/7 = 14.5 cft. Crush = 50.8 × 4/7 = 29 cft.
For a 5-inch slab: cement = 64.2 / 7 / 1.25 ≈ 7.3 bags—buy 8 bags. Sand = 18.3 cft. Crush = 36.7 cft. Always round cement bags up since you can't buy partial bags and leftover opened cement deteriorates quickly.
Practical Pouring and Curing Tips
Wet the subgrade and formwork before pouring to prevent them from absorbing water from the mix. For a slab this size, hand mixing is feasible but a small mixer produces more consistent concrete. Use a water-to-cement ratio of 0.45–0.50 (about 22–25 liters per 50 kg bag).
Cure the slab by keeping it wet for at least 7 days—this can increase final strength by 30–40% compared to uncured concrete. Cover with damp burlap or plastic sheeting and spray water twice daily. For a quick reference: 10×10 ft at 4 inches needs 6 bags cement, 14.5 cft sand, 29 cft crush.
よくある質問
How many bags of cement for a 10×10 slab?
For a 10×10 ft slab with 4-inch thickness using a 1:2:4 mix, you need approximately 6 bags of cement (50 kg each). A 5-inch thick slab requires about 8 bags. Always buy one extra bag as contingency.
What is the best mix ratio for a 10×10 slab?
For a standard patio or utility slab, 1:2:4 (cement:sand:crush) works well, producing M15 grade concrete. For driveways or vehicle-load areas, use a stronger 1:1.5:3 ratio (M20 grade).
How thick should a 10×10 slab be?
For light-duty use (patio, walkway), 4 inches is sufficient. For parking or garage slabs, use 5–6 inches. Roof slabs in residential construction are typically 5 inches (125 mm) thick with steel reinforcement.