20×30 Concrete Slab (4 inches): Yards, Feet & Bags
This 20 ft x 30 ft, 4-inch thick concrete slab is perfect for a driveway section or a large patio. Consider delivery access and whether to use bags or ready-mix for your project.
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Quick Answer
Tip: Always confirm the yield printed on your bag label. Bag yield guide
Large pour: consider ready-mix delivery for speed and consistent results. Bag counts this high can take significant mixing time.
Project Notes (Unique)
Check yield on the label and round to 0.25 yd³ for accurate ordering.
Ensure your base is well-prepared and forms are secure to avoid issues with thickened edges.
Apply a smooth finish and keep the slab moist during curing for best results.
How to Estimate This Slab in 3 Steps
Measure
Length 20 ft, width 30 ft, thickness 4 in.
Compute Volume
Area: 600 sq ft → volume: 200.0 ft³ → 7.41 yd³.
Add Waste
Add a small buffer for spillage and uneven subgrade, then round up when ordering.
Planning Notes
Common uses: driveway section, shop floor, large patio.
For more context and conversions, see the Concrete Calculator hub.
Frequently Asked Questions
What should I consider when choosing between bags and ready-mix concrete?
Consider your project's size, access for delivery, and how quickly you need the concrete to set.
How do I prepare the base for my concrete slab?
Clear the area of debris, ensure proper drainage, and compact the soil to create a stable foundation.
What thickness should I choose for my concrete slab?
A thickness of inches is generally suitable for driveways and patios, but consider heavier loads for thicker options.
How can I minimize waste when ordering concrete?
Estimate your needs carefully, round up your order, and factor in potential spillage or over-excavation.
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