So it seems newly created “bonded loose-fill” -- loose-fill rubber mulch adhered by polyurethane -- is gaining ground when it comes to surfacing playgrounds. While it’s ostensibly an inexpensive alternative to the standard poured-in-place, tile or mat systems, it doesn’t carry the same durability of these other, more time-tested surfaces.
For playgrounds, bonded loose-fill may be an interesting, relatively inexpensive alternative to traditional loose-fill materials such as wood chips, sand or gravel. But there’s no way it can withstand regular, heavy foot traffic over time.
The U.S. Consumer Product Safety Commission broadly holds that surfaces around playground equipment should have at least 12 inches of “wood chips, mulch, sand, or pea gravel, or are mats made of safety-tested rubber or rubber-like materials.” This is to account for the amount of impact absorption necessary to reduce the risk of serious injury resulting when children fall from swings or other playground equipment.
In its April 2008 “Playground Safety Handbook,” the Commission extensively outlines how a safe playground surface should be laid down. It draws the major distinction between “unitary” and loose-fill surfaces: “Unitary materials are generally rubber mats and tiles or a combination of energy-absorbing materials held in place by a binder that may be poured in place at the playground site and then cured to form a unitary shock absorbing surface.”
Regarding loose-fill, page 10 of the handbook indicates that “CPSC staff strongly recommends against installing playgrounds over hard surfaces, such as asphalt, concrete, or hard packed earth, unless the installation adds the following
layers of protection.
“Immediately over the hard surface there should be a 3- to 6-inch base layer of loose-fill (e.g., gravel for drainage),” the handbook continues. “The next layer should be a Geotextile cloth. On top of that should be a loose-fill layer meeting [CPSC] specifications…Embedded in the loose-fill layer should be impact attenuating mats under high traffic areas, such as under swings, at slide exits, and other places where displacement is likely.”
Mind you, none of this is enforceable, these are mere guidelines established by the federal government largely to provide some kind of legal guidance when playground injuries occur, and corresponding lawsuits subsequently filed. It does, however, give a clear example of how quality playground surfaces should be constructed.
The CPSC handbook lists “shredded/recycled rubber” as an acceptable loose-fill playground surface material but makes no mention of bonded loose-fill, an important distinction to note.
Simply put, avoid the polyurethane-bonded rubber mulch. It’s better to spend extra funds for a long-term-friendly rubber surface such as poured-in-place, or to simply but properly lay down inexpensive loose-fill and monitor its rate of compaction.
Bonded rubber mulch may appear to be a less expensive happy medium between poured-in-place, tiles and loose-fill, to the tune of about $6 per square foot less than the other surfaces. But short-term savings can be deceptive -- a lack of durability over time will prove this to be the case.