Playground Mulch Calculator
Engineered wood fiber for under the playset — at CPSC depth?
⚠️ Playground surfacing guidelines follow CPSC publications (test to ASTM F1292 for certified products). The 9-inch figure assumes uncompressed engineered wood fiber — regular landscape mulch does not provide certified fall protection.
How this is calculated
- Volume = length × width × (depth ÷ 12) in cubic feet
- Cubic yards = volume ÷ 27, plus the settling allowance
- Depth guidance follows CPSC playground surfacing recommendations: 9 in uncompressed EWF for structures up to 7 ft fall height
Common questions
How much mulch do I need under a playset?
A 10 × 10 use zone at the CPSC 9-inch depth takes about 2.78 cubic yards — order 3.06 with settling. Bulk delivery of engineered wood fiber is the standard move: that is 42 of the 2 cu ft bags if you insist on bags.
How deep should playground mulch be?
Nine inches of uncompressed engineered wood fiber is the CPSC guideline for protecting falls from up to 7 feet; 12 inches for taller structures. Regular landscape mulch is NOT certified for impact absorption — EWF is engineered, tested, and what daycares are required to use.
Engineered wood fiber vs rubber mulch?
EWF: cheap ($40-80/yd³), natural look, needs raking/top-ups yearly and drainage underneath. Rubber mulch: 2-3× the price but barely compacts, drains well, lasts 10+ years, and meets CPSC at 6 in instead of 9. Both work; EWF wins on budget, rubber on maintenance-free longevity.
How big should the mulch zone be?
At least 6 ft out from every side of the equipment — farther for swings (2× the height of the pivot in front and back) and slides (exit zone plus runout). The fall-height protection only counts where the surfacing is; the equipment footprint alone is never enough.
What goes under playground mulch?
A geotextile weed barrier over graded, draining soil — never plastic (it turns the zone into a bathtub). Edging to contain the EWF is required or it migrates into the grass in months: timber, rubber curbs, or plastic edging all work. Plan a yearly top-up of an inch or two as the fiber packs.