How Much Crushed Stone Under a 12x20 Deck?
How much crushed stone under a 12x20 deck: about 3.1 tons at 3 inches deep. The area is 240 square feet, which is 2.22 cubic yards at that depth.
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 crushed stone calculator does this for any size.
Related: How Much Pea Gravel Under a 12x20 Deck?
Crushed stone needed by depth
| Depth | Cubic yards | Tons of crushed stone | 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
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 #57 Stone Under a 12x20 Deck?
Prep
Clear vegetation, rake the soil level and compact it. Lay fabric overlapped at the seams and set edging before spreading the stone.
Getting it delivered
If you haul it yourself, a typical half-ton pickup should carry only about half a cubic yard of stone, well under what the bed looks like it can hold. Crushed stone has angular faces that lock together under a compactor, which is why it holds a pad shape. 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 crushed stone under a 12x20 deck?
About 3.1 tons at 3 inches deep.
How many yards of crushed stone under a 12x20 deck?
About 2.22 cubic yards.
How many tons of crushed stone 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 Pea Gravel Under a 12x16 Deck?
- How Much Gravel Under a 12x20 Deck?
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.