How Much Pea Gravel Under a 12x20 Deck?
A 12 by 20 foot deck covers 240 square feet. At 3 inches of pea gravel, plan on 2.22 cubic yards, or about 3.1 tons, which answers how much pea gravel under a 12x20 deck.
Volume and tonnage calculator →The math
- Area: 240.0 sq ft.
- Depth in feet: 3 ÷ 12 = 0.250 ft.
- Cubic yards: 240.0 × 0.250 ÷ 27 = 2.22 yd³.
- Tons: × about 1.4 tons per yard = 3.1 tons.
The gravel calculator does this for any size.
Related: How Much Gravel Under a 12x20 Deck?
Pea gravel needed by depth
| Depth | Cubic yards | Tons of pea gravel | Tons +10% |
|---|---|---|---|
| 2 in | 1.48 | 2.1 | 2.3 |
| 3 in | 2.22 | 3.1 | 3.4 |
| 4 in | 2.96 | 4.1 | 4.6 |
| 6 in | 4.44 | 6.2 | 6.8 |
Building the deck base
Gravel under a deck blocks weeds, keeps the ground from turning to mud and lets water drain. Lay landscape fabric first, then about 2 to 3 inches of stone; there is no need to compact it the way you would a driveway base.
Related: How Much Pea Gravel Under a 10x10 Deck?
Prep
Remove sod and roots, level the area and slope it slightly for drainage. Install edging so the stone stays inside the footprint.
Ordering and delivery
Small dump trucks commonly carry around 5 to 10 tons and tri-axles more, but loads vary by truck and state, so ask the yard what fits in one trip. Pea gravel is small and rounded, comfortable underfoot, and needs edging because it rolls. Ask your supplier for their own tons-per-yard number, since stone source and moisture change it.
Common mistakes
The most frequent problem is ordering for the finished depth without allowing for compaction, which can shrink a loose layer by 10 to 20 percent. Another is skipping fabric on soft soil and watching the stone vanish into the mud over the first wet season. Spreading everything in one thick layer instead of compacted lifts also leaves a soft, rutted surface.
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 pea gravel under a 12x20 deck?
About 3.1 tons at 3 inches deep.
How many yards of pea gravel under a 12x20 deck?
About 2.22 cubic yards.
How many tons of pea 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 Crushed Stone Under a 12x20 Deck?
- How Much #57 Stone Under a 12x20 Deck?
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