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Bags of Sand for a 12x20 Patio

How many bags of sand for a 12x20 patio: at 2 inches deep you need about 40.0 cubic feet, which is 80 bags of the common 0.5 cubic foot size. If your store sells sand in 50-pound bags instead, figure about 80 bags, since sand weighs roughly 100 pounds per cubic foot.

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Bag count by depth

DepthCubic feet0.5 cu ft bags50 lb bags (approx.)
1 in20.04040
2 in40.08080
3 in60.0120120
4 in80.0160160

How to figure it

  1. Area: 12 × 20 = 240 sq ft.
  2. Volume: 240 × (2 ÷ 12) = 40.0 cu ft.
  3. Bags: 40.0 ÷ 0.5 = 80 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 40.0 cubic feet is 1.48 yards, about 2.0 tons. At this size, a bulk delivery usually beats a cart full of bags once you count trips. Compare the bag price × 80 against a bulk quote for 2.2 tons delivered.

About sand

Sand weight changes a lot with moisture. Damp sand can weigh noticeably more per yard than dry sand, so a ton of wet sand covers less area than the same ton dry.

Install tips for a patio

  • Dig and level. Remove sod and set the base slightly below the surrounding grade.
  • Edge it. Steel, plastic or stone edging keeps material in place.
  • Spread in layers. Rake to depth, then tamp or wet and compact.
  • Buy a few extra. Grab 5 to 10 percent more bags for settling and touch-ups.

The volume and tonnage calculator handles other sizes and depths.

Good and poor uses for sand

Works well for:

  • Paver and flagstone bedding
  • Leveling under above-ground pools (with the right product)
  • Filling joints and backfilling pipe

Poor fit for:

  • Driveway bases, since sand shifts under load
  • Steep areas exposed to runoff
  • Thick layers under pavers, which settle unevenly

Quick reference numbers

  • Per inch over 100 sq ft: about 0.42 tons of sand (0.31 cubic yards).
  • Per inch over 1,000 sq ft: about 4.2 tons.
  • Another size for comparison: a 8x16 area at 3 inches takes about 1.6 tons.
  • Weight used here: about 1.35 tons per cubic yard.

Where estimates go wrong

  • Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
  • Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.

Questions people ask

How many bags of sand for a 12x20 patio?

About 80 bags of 0.5 cubic feet at 2 inches deep.

How many 50 lb bags of sand for 12x20?

About 80 bags at 2 inches.

How many 0.5 cubic foot bags are in a cubic yard?

54 bags.

How many cubic feet is a 12x20 patio at 2 inches?

About 40.0 cubic feet.

When does bulk make more sense?

Usually once the job passes about a cubic yard, or when you would need more than a few car trips.

Related guides

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