What to Put Under a Swing Set

The decision to use a safe material under your swing set is a great one, as it significantly increases the safety level of your kid's play area. Gorilla's playsets always come with a range of safety features, but what you put under a swing set is just as important as the materials you use to build it. While manufacturers do what they can to make playsets safe for children, adding a surfacing material to the ground gives your playset an extra level of protection.

Below are some of the recommendations that the U.S. Consumer Product Safety Commission (CPSC) offers from its Handbook for Public Playground Safety. The guide can be downloaded in full here.

Fall Zones

A fall zone, covered with a protective surfacing material, is essential under and around equipment where kids might fall. This area should be free of other equipment and obstacles onto which a child might fall. Stationary climbing equipment and slides should have a fall zone extending a minimum of 6’ in all directions from the perimeter of the equipment.

Swings should have a fall zone extending a minimum of 6’ from the outer edge of the support structure on each side. The fall zone in front and back of the swing should extend out a minimum distance of twice the height of the swing as measured from the ground to the top of the swing support structure.

Choosing What Material to Put Under Your Swing Set

The best material to use under a swing set will vary based on your preferences and swing set height. Learn about your surfacing material choices below.

Loose-Fill Materials

Loose-fill materials are traditionally used in residential backyards. Some of the most common loose-fill materials include rubber mulch, wood mulch, sand, and pea gravel. Be aware that loose-fill materials can be choking hazards and may not be ideal for playsets for toddlers.

  • Rubber Mulch

    The best loose-fill surfacing material for taller swing sets is rubber mulch. It's great for shock absorption, substantially reducing the chances of serious injuries during play. Rubber mulch is approved for decks up to 8’ tall. While the initial cost of rubber mulch is higher than other loose-fill materials, it lasts a long time: it does not require the same degree of maintenance because it is made out of synthetic materials.

  • Wood Mulch

    Wood mulch is almost as shock absorbant as rubber mulch, and it has a nice, natural appearance. It does not cost as much as rubber playground mulch, and it is easier to find since it has many uses. On the other hand, wood mulch easily spreads to other parts of the yard (so you may have to deal with clean-up). It is also susceptible to mold and insects because it is made of organic materials.

  • Sand

    Sand can be a fun option for children - it turns their playset into a giant sandbox! It absorbs shock from a 5' fall height at most depths. Like wood mulch, it is not prohibitively expensive, and it's readily available. But also like wood mulch, it tends to get kicked out of the swing set area and end up in other places in your yard. It also requires regular inspection, as objects can easily get lost or hide in the sand.

  • Pea Gravel

    Pea gravel is often used in gardens, dog parks, and other public spaces. You may remember it as the surface material below some of your favorite swing sets in public parks when you were younger. Pea gravel is surprisingly soft to the touch and provides adequate shock absorption under your play structure. But, this loose-fill material is potentially more of a choking hazard than others - small rocks can be appealing to toddlers who like to put objects in their mouths.

Poured-in-Place Surfaces and Rubber Tiles

If loose-fill materials are not your speed, poured-in-place surfaces or rubber tiles may offer the protection you need for your playset.

  • Poured-in-Place Surfaces

    As the name suggests, a poured-in-place surface is playset flooring that is poured into place and left to set. The appeal of this type of material is that it’s customizable, visually appealing, and protective. But keep in mind that pour-in-material is not a DIY option - it requires professional installation.

  • Rubber Tiles

    Rubber tiles are another option to consider. They provide both shock absorption and traction to minimize injury during play. You can install rubber tiles on your own or enlist the help of a professional.

How Much Material to Use

You will need to maintain a minimum depth of at least 9 inches of loose-fill materials (wood mulch/chips, shredded/recycled rubber mulch, or sand/pea gravel) for playset decks up to 8 feet high. Keep in mind that the surfacing will compress over time and will need to be refilled occasionally to maintain the 9-inch depth. Typically an initial fill level of 12 inches will compress to a 9-inch depth over time.

Protective Surfacing Fall Height Guides

Since almost 60% of all injuries are caused by falls to the ground, protective surfacing under and around all playground equipment is the most critical safety factor on playgrounds. Certain manufactured synthetic surfaces also are acceptable; however, test data on shock absorbing performance should be requested from the manufacturer.

Asphalt and concrete do not have any shock-absorbing properties. Similarly, natural and artificial grass should not be used. Their ability to absorb shock during a fall can be reduced considerably through wear and environmental conditions.

Fall Height in Feet From Which a Life-Threatening Head Injury Would Be Greatly Reduced

Type of material 6” Depth 9” Depth 12” Depth
Rubber Mulch 12' Fall Height N/A N/A
Double shredded bark mulch 6' Fall Height 10' Fall Height 11' Fall Height
Wood chips 6' Fall Height 7' Fall Height 12' Fall Height
Fine sand 5' Fall Height 5' Fall Height 9' Fall Height
Shredded Tires* 10-12' Fall Height N/A N/A
Fine gravel 6' Fall Height 7' Fall Height 10' Fall Height

* 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 tests 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 height of the material when it was tested in accordance with ASTM F1292.

It should be recognized that all injuries due to falls cannot be prevented no matter what surfacing material is used.