Updated 5/31/2023
A backyard playground gets the kids outside and active in all kinds of weather, and it keeps them out of your hair when you’ve had it up to here. It also comes with risks—and that’s a good thing.
A large body of research identifies numerous benefits of allowing children to engage in “risky outdoor play,” which is defined as exciting—nay, “thrilling”—activities that may involve challenges, heights, speed, tools, and testing limits, all couched in the possibility of physical injury.
Through risky play, children become more confident, resilient, and independent—and you can probably attest to that if you’re a Gen-X or early Millennial, because you’ve probably done your fair share of trying to parachute off a garage with an umbrella or jump a row of bikes on a rickety homemade skateboard ramp without a helmet. And look at you now!
It’s easy enough for a bunch of experts to say risky play is good for your kid—but it’s another thing entirely when it’s you sending your kid out to risk life and limb in pursuit of confidence and resilience. And that brings us to the matter of the best surface material for the backyard playground. Which playground surfaces are best for preventing injury? And how much of it do you need? And how much does it cost?
I’ve done a deep dive into all things loose-fill playground surface materials, and I’m here with an epic comparison of the five most popular: rubber playground mulch, wood playground mulch, plain old mulch, pea gravel, and sand. Here, you’ll learn how safe each is, how much you’ll need, and roughly how much you can expect to pay for it. If you purchase something I’ve linked to, I may earn a small commission to help keep The Backyard Kid running—so thanks!
What’s the best backyard playground flooring?
The best surface for a home playground depends on a bunch of factors—but first, there’s something important you need to know about all playground surface materials: According to the Consumer Public Safety Commission (CPSC), they’re really only there to protect against life-threatening head injuries—not necessarily cuts ‘n’ scrapes, bumps ‘n’ bruises, broken bones, and other non life-threatening trauma.
To test a playground surface material, ASTM International drops an “instrumental headform” onto a sample of the material to record the “acceleration/time pulse” upon impact. From this data, ASTM calculates the “critical height” rating of the material. Critical height is an estimate of the height below which a fall is unlikely to cause a life-threatening head injury when a child lands head-first on a particular surface.
The following chart lists the critical height and depth for the five most commonly used loose-fill playground surfaces. With the exception of rubber, the depth includes an added three inches recommended by ASTM to account for compaction and settling.
Now, the best surface for your backyard playground isn’t necessarily the “safest” (i.e., six inches of rubber mulch). The best one for you depends on the type of play equipment you have, the age and abilities of your kids, your budget, your personal aesthetic, and how tall the equipment is.
Here are a few things to keep in mind as you decide what material—and how much of it—to put in your play area:
If the critical height for six inches of rubber mulch is 10 feet, but nothing in your play area is taller than five feet, you may not need the full six inches—just sayin’.
The ASTM’s critical height number is only an estimation, based on controlled studies.
Many experts from various disciplines believe that the best safety strategies for risky play are those that keep children “as safe as necessary,” not “as safe as possible.”
Remember, I’m a researcher and writer, not a mathematician or physicist, so I have no idea whether half the critical height only requires half the recommended depth—and I couldn’t find that information on the Internet. So use your own math skills, logic, or gut instinct when you’re deciding how deep your playground surface should be.
If you aren’t a mathematician either, use this handy yardage calculator to figure out how much material you’ll need.
So without further ado, here is everything you need to know about the pros and cons, coverage, and pricing of the various playground materials.
1. Rubber Playground Mulch
If we’re talking purely safety, rubber mulch is the “best” playground flooring, with a critical height of 10 feet at a depth of 6 inches. Rubber playground mulch is made from recycled rubber, and it’s recyclable.
Pros and cons of rubber mulch for playgrounds
Although rubber mulch is the most expensive playground option, it’s one of the most economical—it doesn’t compress, compact, or decompose like other loose-fill surface materials, so you need less of it to begin with—and once you lay it down, you won’t need to replenish it as long as it stays in the playground boundary.
Here are a few other benefits of rubber mulch over other playground surfaces:
It doesn’t contain added chemicals.
It doesn’t attract or harbor pests.
It dries fast and doesn’t freeze.
It comes in lots of fun colors.
It inhibits the growth of mold and fungi.
How much does rubber playground flooring cost?
You can buy rubber mulch in ~1.5 cubic-yard bags at your local home improvement store, but you may be limited to black or brown. In-store and online, a bag will cost you somewhere in the general vicinity of 50 bucks—which isn’t at all economical if you’ve got a big space to fill.
For a larger playground, rubber mulch by the pallet is the most economical way to go. Playsafer on Amazon offers bulk rubber mulch in blue, red, green, brown, and black. You can purchase it in quantities of 16 cubic feet, 39 cubic feet, and 77 cubic feet.
Here’s a breakdown of how rubber much you’ll need, along with a very rough estimate of the cost (including delivery to your curb):
Wood playground mulch, more officially known as engineered wood fiber, or EWF, is one of the most commonly used materials for playground flooring in both public and backyard playgrounds. It’s got a critical height of 10 feet at a depth of 9 inches (plus 3” for compaction = 12”.)
EWF is made from hard and soft woods, which are ground into bark-less chips around one or two inches long. It’s similar to landscaping mulch, but it’s far superior for preventing injury on the playground.
Pros & cons of wood playground mulch
Like rubber mulch, wood playground mulch doesn’t have many down sides, but it’s got lots of benefits over regular mulch, pea gravel, and sand:
EWF is free of CCA, dyes, and other harmful chemicals.
It’s certified by the International Playground Equipment Manufacturers Association (IPEMA) for the absence of foreign metals and hazardous chemicals.
It’s free of twigs and leaves and won’t harbor insects.
It has about 15% fibrous content, which enables it to knit itself together to create a mat-like, wheelchair-accessible surface.
Debris tends to “float” on this matted surface, so it’s easier to keep the playground free from hazardous objects.
EWF doesn’t decompose as fast as regular mulch, so once you fill up the space, you should be good to go for at least a few years, as long as the mulch stays within the playground boundaries.
How Much Does Wood Playground Mulch Cost?
EWF playground mulch is available in bulk from The Home Depot. The smallest order is 5 cubic yards, which covers around 270 square feet (an area roughly 16’ by 16’) at a depth of 12”. The mulch is delivered by dump truck and spilled onto your driveway, alley, or—if there’s access—right into your playground area.
Here’s a ballpark estimate of the quantity you’ll need and the rough cost of wood playground mulch:
In addition to beautifying your flower beds, regular old wood mulch can provide ample cushioning for the backyard playground. The critical height for 12 inches (9” + 3” for compaction) of regular wood mulch is 7 feet.
Pros and cons of regular wood mulch for the playground
The main benefit of regular wood mulch for the playground surface is that it’s fairly inexpensive and easy to come by. But it’s not the ideal surface material (unless you’re specifically looking for cohesion from playground to garden beds!) and here’s why:
It’s dirty, especially when it’s new, so your kids may come in filthy from outside.
It’s often treated with chromated copper arsenate, or CCA, which is no bueno for kids.
It’s often treated with chemical pesticides or herbicides.
It’s rife with splinters if you land the wrong way.
It may harbor bugs, including termites.
It needs to be replenished every year, since it compacts and decomposes quickly.
How much does regular wood mulch cost?
Wood mulch is available in large bags at your local home improvement or garden center, but you’d need quite a few bags—around 60 of them for a 10’ x 10’ play area—and at a cost of roughly $5 per bag, that’s not the best way to go.
You can buy non-toxic, CCA-free landscaping mulch in bulk from The Home Depot. It’s safe for kids and pets, and delivery is free—but if there’s no truck access to the playground, they’ll have to dump it in a big pile in your driveway or alley.
Here’s an estimate of what you can expect to pay for regular landscaping mulch in bulk:
Once upon a time in third grade, I fell off the jungle gym and landed face-first in the pea gravel, resulting in a big, fat, bloody, rock-filled split lip that hurt like hell and took forever to heal. But the pea gravel undoubtedly saved me from some broken facial bones and maybe a couple of lost teeth. The critical height for 12 inches (9” + 3” for compaction) of pea gravel is 5 feet.
Pros and cons of pea gravel in the backyard play area
At the appropriate depth, pea gravel is an economical choice for backyard playground safety. Its edges are rounded for comfort, and it’s uninviting to insects, mold, and microbial organisms. On the down side:
Pea gravel likes to get into your kid’s shoes, which is no fun for anyone.
Pieces of gravel that end up lodged in the kids’ shoe soles can do some serious damage to your hardwood floors.
Gravel may pose a choking hazard to young’uns—supervise your little rock-eater closely.
How Much Does Pea Gravel Cost?
Pea gravel is available in bags at your local home improvement center, but if you’re covering a lot of ground, it’s way more economical to get it in bulk from your local landscaping center or construction material place. In my neck of the woods, bulk pea gravel goes for $81 per ton, plus $60 to $100 for delivery, depending on distance. Based on that price, here’s an estimate of what you’ll pay for pea gravel:
5. Sand
Sand is the cheapest option for the backyard playground, but its critical height is just 4 feet at a depth of 12 inches (9” plus 3” for compaction.) Choose between play sand, AKA washed sand, which is manufactured specifically for sandboxes, and construction sand, which is used in concrete and cement mixes and the like. Here’s the diff:
Play sand has small, evenly sized particles that make it ideal for building sand castles and such. It’s also washed and sieved to remove dirt and debris, which helps keep your kids’ clothes clean.
Construction sand is dirtier, has bigger particles, and won’t stick together as well as play sand. It’s cheaper than play sand, but not by much.
Pros & cons of sand for the backyard playground
Although a large expanse of sand is pretty fun on its own, it has a few distinct downsides when used as playground flooring:
Your kids may not be the only critters drawn to the playground sand—the neighborhood foxes, raccoons, and late-night kitties may mistake your large sandbox for a litter box.
Kids are always getting sprayed in the eyeballs with sand—it’s not particularly dangerous, but it’s very unpleasant for everyone in the vicinity.
Deep playground sand can easily hide sharp things below the surface—so definitely ban all glass and other potential hazards from the play area.
How Much Does Sand Cost?
Play sand is available in bags from your big-box home improvement store, but to fill a 100 square-foot space (10’ x 10’), you’d need around 162 bags, which is a bit unwieldy and not very cost-effective at roughly $5 per bag.
Instead, hit up your local landscaping supply spot and order up your playground sand in bulk. Here’s some ballpark pricing, based on my local landscaping center’s prices (not including $60 to $100 for delivery, depending on distance.)
Install playground borders to keep the loose-fill contained
Whichever surface option you choose, you’ll need to create a border to keep it contained to the playground. The playground border should be at least as high as the recommended depth of the material you’re using.
You can use lumber, bricks, tree stumps, or pre-made borders, like Creative Playthings’ molded plastic playground border, which comes in heights of 6 inches (perfect for rubber mulch) and 12 inches (ideal for other flooring materials.) Sections are 4’ long and 4” wide and connect together with spikes.
How to maintain the playground surface
Keep the playground surface tidy and free of flotsam and jetsam on a regular basis. Periodically, rake the loose-fill to fluff it up, uncover foreign objects, and keep it looking fresh. If the kids tend to kick a lot of the material out of the area, rake it back in often, before it becomes embedded in the lawn.
If you’re using regular old wood mulch, replenish it each season back up to the desired depth. After it rains and the mulch on top has dried, give it a good stirring to help prevent the growth of mold, mildew, and mushrooms. For the other surface materials, check the depth each season, and refill as needed.
Consider the backyard playground “field work” for your kids
You can’t—and apparently shouldn’t!—protect your kids from ever getting hurt out on the playground. One way or another, someone’s eventually going to tumble off the slide, get smacked in the face with a swing, or get an eyeball full of gravel. When the inevitable happens—and it’s not a medical emergency—stay calm, patch ‘em up with what you have on hand, and send them back outside with popsicles all around.
Because according to Those Who Know, kids view injuries as a badge of honor to show they’re fearsome and brave. But at the same time, they’re well aware that too many injuries indicate clumsiness or carelessness—and that’s viewed negatively by their peers. So you can rest a little easier knowing your kid has social incentive to take only calculated risks and proceed with caution, lest they lose their Alpha reputation in the ‘hood.
