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Pea gravel, sand, wood chips or engineered wood fiber for a play area at the CPSC depth, including the 6 ft use zone.
With these inputs:
| Result | Value |
|---|---|
| Pea gravel needed | 43.2 tons |
| Volume | 32 yd³ |
| Or in 0.5 cu ft bags | 1,728 bags |
| Surfaced area incl. use zone | 864 sq ft (32 × 27 ft) |
| Border / containment | 118 ft |
| Equipment footprint | 300 sq ft |
| Use zone added | 6 ft each side |
| Fill depth | 12 in |
| Depth after settling (~25%) | about 9 in |
| Cubic feet | 864 ft³ |
| Density | 1.35 tons per yd³ |
CPSC: fill loose surfacing to 12 in so it settles to about 9 in, and keep it at least 9 in — rake it back under slides and swings where it gets kicked out. Swings need a longer use zone front and back (twice the pivot height), and loose fill should never go over concrete or asphalt.
Loose-fill surfacing under play equipment is a safety layer, so the depth comes from the U.S. Consumer Product Safety Commission rather than taste: fill to 12 inches, which settles to about 9 inches, over the equipment footprint plus a use zone of at least 6 feet on every side. Enter the equipment footprint and material for cubic yards, tons or bags, and the border you need to hold it in.
Fill to 12 inches. The U.S. Consumer Product Safety Commission's Public Playground Safety Handbook notes that a 12 inch initial fill compresses to about 9 inches over time, and 9 inches is the depth its tables work from for most loose-fill materials. Keep a border tall enough to hold the full 12 inches.
Add a 6 ft use zone around the equipment, multiply length × width × 1 ft of depth and divide by 27 for cubic yards, then multiply by about 1.35 for tons. A 20 × 15 ft play set becomes 32 × 27 ft = 864 sq ft, which is 32 cubic yards — about 43.2 tons of pea gravel at 12 inches.
At least 6 feet in every direction from the edge of stationary equipment — the CPSC use zone. Swings need more: the zone in front and behind extends twice the height of the pivot point, so measure those separately and enter the larger footprint.
The same volume as any other loose fill: area × depth. Playground wood chips and engineered wood fiber are sold by the cubic yard or in bags of about 2 cubic feet, so the 864 sq ft example at 12 inches needs 32 cubic yards, or 432 bags. Bulk delivery is usually far cheaper above a few yards.
Not loose fill. The CPSC handbook warns against installing loose-fill materials over hard surfaces such as concrete or asphalt. Over a hard surface use a unitary surface such as poured-in-place rubber or rubber tiles that are tested for the fall height.
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