Protective Playground Surface Options
The protective playground surface is often the most overlooked part of home playground safety. While about 80% of public playgrounds have some type of shock-absorbing protective surfacing under playground equipment, only 9% of home playgrounds do, according to a 2001 playground injury study conducted by the U.S. Consumer Products Safety Commission (CPSC). The study found that, of the roughly 50,000 injuries annually associated with home playground equipment, 69% of the injuries were a result of falls to a non-protective surface below the equipment.
Most commonly, backyard playgrounds sit on top of grass and dirt, but neither surface provides adequate protection against serious injury due to falls, even falls from 30 inches or less above the ground. Fractures of the arms and hands, and lacerations and contusions of the head and face are the most commonly reported injuries that result from a child falling from playground equipment to a non-protective playground surface such as grass or dirt, as reported by the CPSC.
Luckily, there are a variety of protective playground surface choices for the home playground that meet the need for playground safety. Not surprisingly, playground surfaces range in cost from affordable to expensive, and each choice has its own list of advantages and disadvantages. By comparing and contrasting each type of playground surface material, as presented in this article, you should be able to choose the most suitable playground surface for your home playground.
Critical Height of Home Playground Equipment
The first and most important piece of information to know when considering the available choices for your protective playground surface is critical height. Critical height refers to the “maximum fall height from which a life-threatening head injury would not be expected to occur.” The critical height of your playground equipment equals the height (in feet) of the uppermost part of your playground equipment that is accessible to children. The protective playground surface you select for your home playground should be installed with a depth that is adequate for your equipment’s critical height.
The following table shows the critical height (in feet) for each of the loose-fill surface materials described in this article “when tested in an uncompressed state at depths of 6, 9, and 12 inches. The table also shows the critical height when a 9 inch depth of each material was tested in a compressed state.”
6 Inch Depth
9 Inch Depth
12 Inch Depth
9 Inch Depth
|Wood Chips*||7 ft||10 ft||11 ft||10 ft|
|Shredded Bark Mulch||6 ft||10 ft||11 ft||7 ft|
|Engineered Wood Fibers**||6 ft||7 ft||12 ft||6 ft|
|Fine Sand||5 ft||5 ft||9 ft||5 ft|
|Coarse Sand||5 ft||5 ft||6 ft||4 ft|
|Fine Gravel||6 ft||7 ft||10 ft||6 ft|
|Medium Gravel||5 ft||5 ft||6 ft||5 ft|
|Shredded Tires***||10-12 ft||N/A||N/A||N/A|
*This product was referred to as Wood Mulch in previous versions of the handbook. The term Wood Chips more accurately describes the product.
**This product was referred to as Uniform Wood Chips in previous versions of the handbook. In the playground industry, the product is more commonly known as Engineered Wood Fibers.
***This data is from tests conducted by independent testing laboratories on a 6 inch depth of uncompressed shredded tire samples produced by four manufacturers. The test results reported critical heights which varied from 10 feet to greater than 12 feet. It is recommended that persons seeking to install shredded tires as a protective surface request test data from the supplier showing the critical heights of the material when it was tested in accordance with ASTM F1292.
As an example, if the critical height of your home playground equipment is 8 feet, then your options, according to the table above, would be 9 inches of compressed or uncompressed wood chips, 9 inches of uncompressed shredded bark mulch, 12 inches of uncompressed play sand, 12 inches of uncompressed pea gravel, or 6 inches of uncompressed recycled rubber mulch. Being aware of some of the advantages and disadvantages of loose-fill surface materials will allow you to narrow the options to meet your particular needs.
Alternatives to loose-fill surface materials are rubber playground tiles, rubber mats, and poured-in-place playground surfaces. These options are offered by a number of manufacturers who may use a variety of shock-absorbing materials. The manufacturers should be able to give you test data that shows the critical height for the protective surfaces they offer.
Loose-Fill Playground Surface Choices
In general, loose-fill playground surface materials like wood chips, shredded bark mulch, pea gravel, play sand, and recycled rubber mulch are most frequently chosen for home playgrounds because they are relatively inexpensive and easy to acquire from a local garden center or home improvement warehouse. Recycled rubber mulch can also be found in a number of colors and sizes through internet suppliers.
Common Features of Loose-Fill Playground Surface Materials
- A retaining barrier of some kind is necessary for preventing the surface materials from displacement due to active play or weather conditions.
- Loose-fill materials should never be placed on top of hard surfaces like concrete or asphalt.
- Adequate drainage beneath the protective surface is important.
- The initial expense of installing a loose-fill playground surface under your home playground equipment is generally low because the materials are easy to find and are affordable.
- Over time, loose-fill materials can become compressed, thus reducing their protective abilities.
- Recommended depths can be compromised when active play or windy conditions displace the loose-fill materials.
- Rubbish such as broken glass, nails, and other sharp objects which can cause injury can be easily concealed by loose-fill materials.
- Regular upkeep is required to maintain proper depth and to remove rubbish. Upkeep can include raking, sifting, grading, and leveling.
- Routine renewal or replacement of loose-fill materials is necessary, which can be time consuming and costly. The exception to this is recycled rubber mulches (see below for more detail).
Wood Chips and Shredded Bark Mulch
- Wood chips and shredded bark mulch are less abrasive than play sand.
- Animals are less likely to soil wood chips and shredded bark mulch.
- Wood chips and shredded bark mulch are aesthetically pleasing.
- The protective ability of wood chips and shredded bark mulch is decreased in rainy, humid, and freezing weather conditions.
- Over time, wood chips and shredded bark mulch will become crushed, compacted, and will decompose.
- Wood chips and shredded bark mulch can develop fungus and mold when wet.
- Insects are attracted to wood chips and shredded bark mulch.
- Pea gravel will not crush and decompose.
- Mold and fungus growth are not generally an issue.
- Animals and insects are less attracted to pea gravel.
- Pea gravel can be a challenge to walk on.
- The protective ability of pea gravel is decreased in rainy, humid, and freezing weather conditions.
- Pea gravel can be a falling danger if displaced from the playground area to a nearby hard surface (sidewalk, decking, or patio, for example).
- Play sand will not crush and decompose.
- Mold and fungus growth are not generally an issue.
- Play sand can be a challenge to walk on.
- The protective ability of play sand is decreased in rainy and humid weather conditions.
- Animals are attracted to sand unless it can be covered when not in use.
- Play sand sticks easily to shoes, clothing, and skin.
- Play sand can scratch floor surfaces if tracked inside.
Recycled Rubber Mulch
- Recycled rubber mulch does not generally need to be replaced or renewed each year. Many manufacturers claim that rubber mulch can last about 50 years without needing replacement. Check with recycled rubber mulch suppliers for any guarantees or warrantees that may be available.
- Rubber mulch tends to be cleaner and less apt than other loose-fill materials to cause dirty clothing, hands, and shoes during active play.
- Does not cause scrapes, scratches, or splinters from falls.
- Animals and insects are not attracted to rubber mulch.
- Mold and fungus growth are not an issue.
- Recycled rubber mulch may need to be raked routinely to maintain adequate depths in high traffic areas.
- Colors on recycled rubber mulch may fade over time.
Other Protective Playground Surface Options
Rubber Tiles, Rubber Mats, and Poured-in-Place Surfaces
Rubber tiles, rubber mats, and poured-in-place surfaces are initially more expensive surface options than loose-fill materials, but they generally need very little upkeep over time. To determine whether one of these choices would be more cost effective than a loose-fill material, consider how many children might potentially use your home playground equipment and for how many years. Larger families, for example, may prefer to pay more on the front end for a surface that will be easier and much less expensive to maintain over many years of active use.
- No containment barriers are usually necessary.
- Surfaces are accessible to wheelchairs and easy to walk on.
- Displacement of materials is not an issue, so the protective ability of these surfaces remains consistent even in high traffic areas.
- Surfaces require very little upkeep over time and are easy to clean.
- Rubbish such as broken glass and other sharp objects which can cause injury are not easily hidden in these surfaces.
- Animals and insects are not attracted to the surface materials.
- Mold and fungus growth are not an issue.
- The area under the surface usually requires special preparation. Contact the manufacturer or supplier for details.
- Surfaces may require professional installation.
- Rubber tiles may curl and cause tripping if not installed correctly.
- Some surfaces may be damaged by frost.
In summary, no protective playground surface of any type or depth can prevent all injuries. Nonetheless, installing a protective playground surface as the foundation for your home playground equipment is vital for improving playground safety. The most suitable playground surface for your needs is up to you, but whatever option you choose will be a significant step toward protecting children from serious injuries due to falls to the surface.
CPSC Document #323. “Home Playground Safety Tips.”
CPSC Document #324 “Outdoor Home Playground Safety Handbook.” 2005.
CPSC Document #1005. “Playground Surfacing Materials.”
CPSC Report. “Home Playground Equipment-Related Deaths and Injuries.” July 2001.
CPSC Report. “Special Study: Injuries and Deaths Associated with Children’s
Playground Equipment.” April 2001.