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How Much #57 Stone for a 8x20 Shed Base?

How much #57 stone for a 8x20 shed base is a quick volume problem. 160 square feet at 4 inches comes to 1.98 cubic yards. #57 stone usually weighs about 1.3 to 1.45 tons per cubic yard, so plan on roughly 2.7 tons.

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The math for a 8x20 shed base

  1. Area: 8 × 20 = 160 sq ft.
  2. Depth in feet: 4 ÷ 12 = 0.333 ft.
  3. Cubic feet: 160 × 0.333 = 53.3 cu ft.
  4. Cubic yards: ÷ 27 = 1.98 yd³.
  5. Tons: × 1.35 = 2.7 tons.

The volume and tonnage calculator does this for any size.

#57 stone needed by depth

DepthCubic yardsTons (approx.)Tons +10%
2 in0.991.31.5
3 in1.482.02.2
4 in1.982.72.9
6 in2.964.04.4

About #57 stone

Since #57 is washed and open-graded, it moves a little underfoot. Many installers put it over a compacted base of a dense-graded stone rather than straight on soil. Weight per yard is a planning number; the scale ticket at the yard is the real one.

Preparing the shed base

Level the footprint, extend the stone a foot or so beyond the shed walls for drip and drainage, and compact in lifts. A timber or block border holds the pad shape. For a shed floor frame, the depths in the table above are a reasonable starting range.

Ordering tips

  • Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
  • Delivery size. 2.9 tons fits in a single typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
  • Bulk vs bags. At this size bulk delivery is usually the practical choice.
  • Where it drops. Have the truck dump as close to the shed base as firm ground allows.

When to choose #57 stone

Best suited to:

  • French drains and drainage layers
  • The top course of a gravel driveway
  • Under sheds where water needs to drain away

Think twice for:

  • A standalone base, since it does not pack hard without fines
  • Paver setting beds
  • Walk paths meant for strollers or wheelchairs

Quick reference numbers

  • Per inch over 100 sq ft: about 0.42 tons of #57 stone (0.31 cubic yards).
  • Per inch over 1,000 sq ft: about 4.2 tons.
  • Another size for comparison: a 8x16 area at 2 inches takes about 1.1 tons.
  • Weight used here: about 1.35 tons per cubic yard.

Mistakes that throw off the order

  • Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
  • Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
  • Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.

Questions people ask

How many tons of #57 stone for a 8x20 shed base?

About 2.7 tons at 4 inches deep, or 2.9 tons with 10 percent extra.

How many cubic yards is a 8x20 shed base at 4 inches?

About 1.98 cubic yards.

How much does a cubic yard of #57 stone weigh?

Usually around 1.3 to 1.45 tons, depending on stone size, fines and moisture.

How deep should #57 stone be for a shed base?

The table above shows 2 to 6 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 8x20?

160 square feet.

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