How Much Gravel Under a 16x20 Deck?
How much gravel under a 16x20 deck: about 4.1 tons at 3 inches deep. The area is 320 square feet, which is 2.96 cubic yards at that depth.
Volume and tonnage calculator →The math
- Area: 320.0 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic yards: 320.0 × 0.250 ÷ 27 = 2.96 yd³.
- Tons: × about 1.4 tons per yard = 4.1 tons.
The gravel calculator does this for any size.
Related: How Much Crushed Stone Under a 16x20 Deck?
Gravel needed by depth
| Depth | Cubic yards | Tons of gravel | Tons +10% |
|---|---|---|---|
| 2 in | 1.98 | 2.8 | 3.0 |
| 3 in | 2.96 | 4.1 | 4.6 |
| 4 in | 3.95 | 5.5 | 6.1 |
| 6 in | 5.93 | 8.3 | 9.1 |
Deck tips
Under a deck, stone is a weed and moisture barrier rather than a structural layer. Slope the soil away from the house, lay fabric and spread 2 to 3 inches of washed stone that drains quickly.
Related: How Much Pea Gravel Under a 16x20 Deck?
Prep
Remove sod and roots, level the area and slope it slightly for drainage. Install edging so the stone stays inside the footprint.
Getting it delivered
Most quarries and landscape yards deliver by the ton; ask whether there is a minimum and a delivery fee, and where the driver can dump without damaging your lawn. Gravel is a broad label, so confirm whether the yard means crushed or rounded stone and whether it carries fines. Round up by about 10 percent for compaction and uneven ground.
Measuring the area
Use a long tape and measure each side twice. If the ground slopes, measure depth at the high and low ends and average them. Irregular outlines can be broken into simple rectangles, triangles and circles; add the pieces for the total square footage before converting to tons.
Tools for the job
A flat shovel, a steel rake, a wheelbarrow and a rented plate compactor cover most residential pads. A landscape rake or the back of a rake levels the top layer, and a long straightedge or a level string shows high and low spots before the final pass.
Questions people ask
How many tons of gravel under a 16x20 deck?
About 4.1 tons at 3 inches deep.
How many yards of gravel under a 16x20 deck?
About 2.96 cubic yards.
How many tons of gravel are in a cubic yard?
Roughly 1.4 tons for planning, but suppliers vary with stone size and moisture.
Should I put landscape fabric under the stone?
On soft or clay soil, a woven geotextile keeps stone from sinking into the dirt and makes the layer last longer.
Related guides
- Gravel Under a Deck: Weeds, Drainage, and Depth
- How Much Does a Ton of Gravel Cover? Depth Chart
- Tons to Cubic Yards for Gravel: Conversion Chart
- Crushed Stone vs Gravel: Differences and Best Uses
- Geotextile Fabric for Driveways: Woven vs Nonwoven and How Much You Need
- Compacting a Driveway Gravel Base in Lifts
- How Much #57 Stone Under a 16x16 Deck?
- How Much Pea Gravel Under a 16x16 Deck?
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