20×20 Concrete Slab (6 inches): Yards, Feet & Bags
A 20 ft x 20 ft concrete slab serves well as a sturdy patio or gazebo base. Decide between bagged concrete or ready-mix based on your delivery access and project scale.
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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)
When ordering, round to 0.25 yd³ and confirm delivery access for the truck.
Ensure your base is properly leveled and forms are secure to prevent shifting or uneven surfaces.
Finish the surface as desired and allow it to cure naturally, keeping it moist for optimal strength.
How to Estimate This Slab in 3 Steps
Measure
Length 20 ft, width 20 ft, thickness 6 in.
Compute Volume
Area: 400 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: patio, gazebo base, walkway section.
For more context and conversions, see the Concrete Calculator hub.
Frequently Asked Questions
What’s the best option for mixing concrete, bags or ready-mix?
Choose bags for smaller projects with limited access, while ready-mix is suitable for larger areas needing efficient delivery.
How should I prepare the base for my slab?
Clear the area of debris, level the ground, and compact it to create a stable foundation.
What thickness should I choose for my slab?
A thickness of inches is generally recommended for patios and walkways to support weight and resist cracking.
How do I account for waste when ordering concrete?
Always plan for extra material to cover spills, over-excavation, or miscalculations; this helps ensure you have enough for your project.
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