8×20 Concrete Slab (6 inches): Yards, Feet & Bags
An 8 ft x 20 ft concrete slab is perfect for a patio or a gazebo base. 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)
When ordering, round to 0.25 yd³ and check yield on the label to ensure you have enough material.
Ensure your base is well-prepared and forms are sturdy, especially if you're adding thickened edges.
Apply a smooth finish and keep the slab moist during curing for optimal strength.
How to Estimate This Slab in 3 Steps
Measure
Length 8 ft, width 20 ft, thickness 6 in.
Compute Volume
Area: 160 sq ft → volume: 80.0 ft³ → 2.96 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 should I consider when choosing between bagged concrete and ready-mix?
Consider your project's location and access; ready-mix is often easier for large pours, while bags offer flexibility for smaller jobs.
How do I estimate the right amount of concrete needed for my slab?
Measure the area accurately and always include a buffer for waste, as it's common to miscalculate or have spillage.
What is the best way to prepare the base for my concrete slab?
Clear the area of debris, ensure proper drainage, and compact the soil to create a stable foundation for your slab.
How thick should my concrete slab be for a patio or walkway?
A thickness of inches is generally sufficient for patios and walkways, providing durability and support for foot traffic.
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