Play Bark Calculator

Key Takeaways

• To work out the play bark you need in litres, take the area in m² times the depth in mm, and add 15% for settling. At the recommended 200mm, every square metre takes 200L, so a 1,000L bulk bag covers 5m².
• Play bark and play chip are best laid at 200mm, which holds a safe depth without constant checking. 300mm is the optimal safety depth where the budget allows, and 100mm is the tested minimum.
• Every play bark and play chip Outdoor Aggregates sells holds a BS EN 1177:2018 certificate, and the five tested by Labosport are rated above 3m at 100mm, 200mm and 300mm alike. Extra depth buys margin against wear.
• Play bark settles by 10 to 15% of its depth in the first few weeks, so an order normally carries 15% extra. The calculator offers 10, 15, 20 or 25%, and the higher settings cover the first top-up in the same delivery.
• A mark painted on each equipment leg at the right depth helps to quickly see if there's any problem. Bark covering the mark is fine, a mark showing means rake it back level, and a mark that raking cannot cover means it is time to top up.

The hollow under a swing is bigger than people picture. On public play areas it reaches around 2.4m long and 130mm deep before anyone thinks to look, dug out a heel at a time by children doing exactly what the swing is for. The bark gets kicked backwards, trodden down and rained on, and very often nobody puts any back.

That is the reason this calculator works the way it does. It asks for a depth, adds the settlement allowance, and then finds the closest bag order and the cheapest one from our live shop prices. Choose your product first, because bag sizes differ between them. Choose from the three depth buttons that our play barks were tested at, or type your own figure if you like. Then press "Take me there" and the product page opens with your measurements already filled in.

How Much Play Bark Do I Need?

Play bark quantity is area times depth: a square metre at 100mm needs 100L, at 200mm needs 200L, and at 300mm needs 300L. Here is a 5m by 4m play area in Pine Play Bark, at my usual 200mm:

• Area: 5m x 4m is 20m².
• Bark: 20m² x 200L is 4,000L.
• Settling: add 15%, which makes 4,600L.
• With a bulk bag: one 1,000L bulk bag plus a 60 x 60L pack is exactly 4,600L, for £650.
• Without a bulk bag: a 60 x 60L pack plus a 30 x 60L pack is 5,400L, for £730. Keep the spare 800L for the first top-up.

Measure the whole area the bark will cover, not just the footprint of the frame. Children fall off the sides of things, and they jump off swings at the top of the arc, so the surface has to run well past the equipment. Your equipment manual states the impact area it needs, and that figure is the one to measure. If you came here for bark on a flower bed, use the wood chip and bark calculator instead.

Play Bark Coverage Per Bag and Bulk Bag

How Deep Should Play Bark Be?

Play bark should be laid at 200mm in a garden play area, and 300mm gives the optimal safety margin if the budget allows. Each of our products was tested to BS EN 1177:2018 at 100mm, 200mm and 300mm, and every result at every depth came back the same: a critical fall height (the highest fall the surface is rated to absorb) above 3m. Identical results look odd until you know why. Testing stops at a 3m drop because 3m is the highest free fall that BS EN 1176-1 allows on compliant play equipment. So "above 3m" means the material is rated beyond the tallest fall the equipment standard allows, at every tested depth.

So why did I always lay 200mm when 100mm passes? Because 100mm does not stay 100mm. The lab tested fresh bark, spread evenly on a hard floor. A garden surface gets trodden down, kicked thin under the swing, soaked all winter and slowly rotted from below. The depth that protects a child is the depth under them on the day they fall.

If you are still deciding whether ordinary bark will do, play bark vs garden bark covers what separates the two, and the play bark range and play chip range put our grades side by side.

What Goes Under Play Bark?

A heavy duty membrane goes under play bark, laid straight onto the soil once the turf has been lifted, to keep the bark and the soil apart. Lift the turf first. Grass left underneath carries on growing for a while, then rots into a soft, uneven layer that the bark sinks into. Once the soil is bare and roughly level, the membrane goes down and the bark goes on top.

Some people are firmly against weed fabric, and I understand why. Under a flower border it stops weeds for a season or two and then the weeds come back anyway. Under a play area the membrane has a different job. Without it, 200mm of bark slowly works down into the soil while the soil works up into the bark, and after a few seasons you have a thinner, muddier surface than the one you paid for. With it, the bark stays bark, and every top-up goes onto a clean layer.

Check the drainage before you dig. On heavy clay or ground that holds water after rain, build the play area up rather than digging it down, because a pit fills with water and wet bark rots from the bottom. A strong edge, such as log roll, keeps the bark in place on a raised area. There is more on both in garden play areas: what to decide before you build, and the membrane itself is our heavy duty weed membrane.

Also, leave a 5 to 10cm gap round any tree trunk inside the play area, so the bark is not piled against the bark of the tree.

Why Play Bark Is Sold in Litres, Not Tonnes

Play bark is sold by volume because bark and compost are measured loose, in litres, under BS EN 12580, the standard for measuring soil improvers and growing media. Weight would tell you very little anyway. The same bag could gain 30% in weight after a wet week, and none of that water cushions a fall. Bark also compacts in the bag. Tip it out and rake it loose and you get your litres. Spread it flat while it is still compressed, and you will swear the bag was short.

How Much Extra Should I Order for Settlement?

Play bark needs a 15% over-order as standard, because it loses 10 to 15% of its depth to settling in the first few weeks. A play surface loses more than a border does, since it is laid deeper and then gets a summer of feet. Order the exact calculated volume and you can end up paying for a second delivery within months. Set the calculator to 20% for a busy play area, or 25% to buy the first top-up now and keep it bagged for later.

Does a Garden Play Area Have to Meet BS EN 1177?

A private garden play area is not legally required to meet BS EN 1176 and BS EN 1177. Those standards cover public and commercial play, such as playgrounds, schools and nurseries. I worked to the certified depths anyway, and I would not build a garden play area to anything less. A child falling in your garden lands just as hard as one falling in a park.

Why Play Bark Disappears Under Swings and Slides

Play bark thins from the landing zones first. Inspections of wood fibre play surfaces find displaced material under the swings and slides at every site checked, with kick-out hollows at a swing reaching 2.4m long and 130mm deep. That is what a swing does to loose fill.

Test surfaces already in use rather than fresh samples and the results follow: 42 drop points across 19 playgrounds, almost 55% failing the standard they were built to. Those were public playgrounds with someone paid to rake them. Both studies are American. They are the only research I could find on surfaces in use, because no testing of this kind has been published in the UK.

A garden has nobody paid to rake it, which is why I would put the extra depth in at the start, while it costs one more bag rather than a second delivery. Everything that happens before the bark goes down, siting, sizing and what sits underneath, is in garden play areas: what to decide before you build.

Keeping the Depth You Paid For

The simplest way to keep play bark at a safe depth is a mark on every equipment leg that stands in the bark, at the depth you laid.

PRO TIP: I picked this trick up from commercial playgrounds. Paint, tape or scratch a line on each leg at 200mm, or whatever you laid. Bark covering the mark is fine. A mark showing means rake the surface back level. Raking that will not bury the mark means order more. It turns depth checking into a glance on the way past, and it catches the hollow under the swing months before a bare patch does.

Get your kids to help rake the busy spots back level every few weeks through summer, or whenever the equipment markers show. Also, check the depth once a year, and top up to the depth you first laid. The bark is a natural material doing what natural materials do, and the top-up is part of the price of a surface that is soft, free-draining and kind to knees.

Next Steps

We stock all six certified play barks and chips: Softwood Play Grade Chips, Hardwood Play Grade Chips, Pine Play Bark, Pine Play Nuggets, Deluxe Pine Play Area Bark and Deluxe Pine Play Nuggets, in bulk bags, jumbo bags and packs of small bags, with the test reports available on request. Run your measurements through the calculator above, choose your product, and press "Take me there" to order it with your figures filled in. If you would like to talk your play bark quantities through with a person, call Outdoor Aggregates on 0330 043 7585. The office is open 7am to 7pm, seven days a week.

Have you ever laid play bark under a swing or climbing frame? Which product did you go for, and how deep did you lay it? We would love to hear how it has held up. Enjoy the soft landings!

FAQs

How much will 100L of bark chippings cover?

A 100L bag of bark chippings covers 1m² at 100mm deep, 0.5m² at 200mm, and about 0.33m² at 300mm. On play depths, small bags suit top-ups better than filling a whole area.

How much does 1m³ of play bark cover?

A cubic metre of play bark, which is 1,000L or one bulk bag, covers 5m² at the recommended 200mm. The same bag covers 10m² at 100mm and about 3.3m² at 300mm.

Is 10cm of play bark enough?

A 10cm layer of certified play bark is the tested minimum, and our certificates show a critical fall height above 3m at that depth. I still recommend 200mm, because 100mm laid becomes less than 100mm by winter, and the depth that counts is the depth actually under the child.

What is the difference between bark chippings and play bark?

Play bark is screened for size and tested to BS EN 1177 for impact absorption, and ordinary bark chippings are neither. Garden bark on a play area is a guess where a certificate exists, and the two cost close enough that the guess is not worth it.

Do I need a membrane under play bark?

A membrane under play bark keeps the bark and the soil apart, so the depth you laid stays bark. Use a heavy duty, permeable membrane so the surface still drains, and fit it before the equipment goes in.

Is bulk play bark cheaper than buying bags?

Bulk play bark is usually cheaper per litre than packs of small bags, but compare the delivered price for the whole order. The prices in our calculator leave out delivery, so check the delivery charge at checkout before you choose between the two boxes.

Can I mix two sizes of play bark or chip?

Mixing two grades of play bark or chip will not harm anyone, but each certificate covers its product as it was tested, so a mix is no longer the certified material. For a top-up, use the same product you laid first.

How often should play bark be topped up?

Play bark needs checking once a year and topping up to the depth you first laid, with a rake back into the busy spots every few weeks through summer. The marks on the equipment legs tell you when it is due.