16×18 Concrete Slab (4 inches): Yards, Feet & Bags
This 16 ft x 18 ft concrete slab, 4 inches thick, is perfect for a patio or gazebo base. Decide between bags or ready-mix based on your site access and desired 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)
Check yield on the label and round to 0.25 yd³ to ensure you order enough material for your project.
Ensure your base is well-prepared and forms are secure to prevent shifting, especially with thickened edges.
Apply a smooth finish and keep the slab moist during the curing process to achieve optimal strength.
How to Estimate This Slab in 3 Steps
Measure
Length 16 ft, width 18 ft, thickness 4 in.
Compute Volume
Area: 288 sq ft → volume: 96.0 ft³ → 3.56 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 bags and ready-mix?
Consider your project size, access for delivery, and whether you have the means to mix on-site.
How much extra material should I account for?
It's wise to include a buffer for waste, especially if you're unsure about your measurements or conditions.
What is the best way to prepare the base for my slab?
A well-compacted base of gravel or crushed stone is essential for stability and to prevent cracking.
How thick should my slab be for a patio?
A thickness of around four inches is typically suitable for most patio applications, providing adequate strength.
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