20×30 Concrete Slab (6 inches): Yards, Feet & Bags
This 20 ft x 30 ft slab is perfect for a driveway section or shop floor. Decide between bags or ready-mix based on your access and waste factor.
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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)
Always round to 0.25 yd³ when ordering and check yield on the label to ensure you have enough material.
Ensure your base is well-prepared and forms are secure to prevent shifting or cracking.
Apply a smooth finish and keep the slab moist during curing to enhance strength and durability.
How to Estimate This Slab in 3 Steps
Measure
Length 20 ft, width 30 ft, thickness 6 in.
Compute Volume
Area: 600 sq ft → volume: 300.0 ft³ → 11.11 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 is the best option, bags or ready-mix?
Bags offer flexibility for smaller projects, while ready-mix is efficient for larger slabs, reducing labor and time.
How much waste should I account for?
It's wise to include a buffer for waste, as spills and over-excavation can occur during mixing and pouring.
How should I prepare the base for the slab?
The base should be compacted and level, ensuring it can support the slab's weight and prevent cracking.
What thickness should I choose for my slab?
A thickness of inches is recommended for heavy loads, but consider the specific use case to determine if adjustments are necessary.
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