Question 1

How do you calculate concrete cubic yards for a monolithic slab with a perimeter grade beam?

Accepted Answer

Multiply slab width by length by deck thickness (in feet) to get interior slab cubic feet, add the perimeter length multiplied by the deepened edge beam cross-section, divide total cubic feet by 27 to convert to cubic yards, and add an 8% allowance for subgrade unevenness and trench overbreak.

Question 2

What is the average cost per square foot for a reinforced concrete slab in 2026?

Accepted Answer

In 2026, batch-plant ready-mix concrete material alone averages $2.75 to $4.10 per square foot ($162 to $176 per cubic yard). Turnkey monolithic concrete slab installation (including forming, vapor barrier, deformed rebar grid, perimeter grade beam, placement, and power-trowel finish) ranges from $7.24 to $15.25 per square foot, with a regional median of $11.25 per square foot.

Question 3

How many 80-lb bags of concrete equal 1 cubic yard?

Accepted Answer

One cubic yard of concrete (27 cubic feet, weighing approximately 4,050 lbs) requires 45 pre-mixed 80-lb bags or 60 pre-mixed 60-lb bags. For pours exceeding 2 cubic yards, ordering bulk ready-mix delivery via 9-yard transit mixer trucks is significantly more cost-effective and structurally uniform.

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