Play Bark Calculator: How Much Do You Need For Safe Play Area?

Key Takeaways

• Play bark is sold by volume, not weight, so accurate calculators work in litres. At 100mm deep you need 100L per square metre, at 200mm you need 200L, and at 300mm you need 300L.
• A 1,000L bulk bag of play bark covers 10m² at 100mm deep, 5m² at 200mm and 3.3m² at 300mm. A 2,000L jumbo bag doubles each of those figures.
• With certified play bark, laying deeper than 100mm does not buy a higher safety rating. Extra depth buys margin against compaction, loss and rot that thins a play surface over the years, which is why I lay at 200mm and top up less often.
• Play bark does not thin evenly. It gets kicked out of the landing zones first, and the hollow under a swing can reach 2.4m long and 130mm deep, so the depth protecting a child is whatever is left under that swing.
• Play bark loses 10 to 15% of its depth to settling in the first few weeks, so order 15% over as standard and 20% on a deep play surface. The allowance selector in our calculator runs from 10% to 35%, to also allow for top-ups.
• A private garden is not legally bound by BS EN 1176 and 1177, which govern public and commercial play provision. It’s still best to work to certified depths anyway, because a big fall does not care where it happens.

The hollow under a swing is bigger than people picture. On public play areas it often reaches around 2.4m long and 130mm deep before anyone thinks to look, dug out a heel at a time by children playing. The bark gets kicked backwards, trodden down and rained on, and often not replenished.

Our calculator does two jobs. It works out the volume, and calculates the closest number of bags required for the area you give it. It also allows you to toggle between different options that allow for the expected settlement and for future top ups. It is designed for our certified play barks and chips only. So, just put in your measurements, set the depth, and then pick the product - it returns litres plus the combination of bags to order. The depth toggle offers 100mm, 200mm and 300mm because those are the three tested depths on our test certificates.

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, at 300mm needs 300L. So a 5m x 4m area at my usual 200mm is 20m² x 200L, which is 4,000L before the settlement allowance, or five 1,000L bulk bags once you add 15% and round up.

Measure the whole area the bark will cover, not just the footprint of the equipment. Children fall off the sides of things, not neatly underneath them, so the surface has to run well past the frame. Your equipment manual states the impact area it needs; work from that rather than from a blanket figure, because a 2.4m swing and a toddler slide do not need the same apron.

If you ended up here for the non-play safety stuff, use the bark and wood chip calculator instead.

Play Bark Coverage Per Bag and Bulk Bag

How Deep Should Play Bark Be?

Play bark should be laid deep enough to still hold a certified depth after it settles. Each of our products was tested by Labosport to BS EN 1177:2018 at 100mm, 200mm and 300mm, and every result at every depth came back the same, a critical fall height greater than 3m.

Identical results at three depths look odd until you know why. Testing stops at a 3m drop because 3m is the highest free fall that BS EN 1176-1 permits on compliant play equipment. Greater than 3m means the material is rated beyond the tallest fall the equipment standard allows, at every tested depth.

So why do I lay 200mm when 100mm passes the test? Because 100mm does not stay 100mm. The lab tested fresh bark, evenly spread on a hard floor. Your 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, not the depth you ordered. 200mm is what keeps you above the minimum once the garden has had its go.

If you are still deciding whether normal bark will do, play bark vs garden bark covers what separates play grade from ordinary garden bark and what the certificates actually say.

Why Play Bark Is Sold in Litres, Not Tonnes

Play bark sells by volume because the measuring standard for barks and composts, BS EN 12580, measures the material loose and fluffed up. Weight would be useless anyway, since the same bag gains a third after a wet week and none of that water cushions anything. The thing is, bark compacts in the bag, so tip it out and rake it loose and you get your litres. Spread it flat and 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, and 20% for deep surface, because it loses 10 to 15% of its depth 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 will be paying a second delivery charge within months. Anything above 20% on the selector buys that top-up now instead.

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 1177. Those standards cover public and commercial play provision, playgrounds, schools and nurseries. I work to the certified depths anyway, and I would not build a garden play area to anything less. But, a child falling in your garden lands just as hard as one falling in a park - you just don’t get the monthly inspections.

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 not neglect. 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. Your garden has nobody, which is why I would put the extra depth in at the start, while it costs one more bag rather than a second delivery.

Image courtesy of Lisa Burch from Pixabay

Keeping the Depth You Paid For

PRO TIP: A trick I have picked up from commercial playgrounds, mark your chosen depth on every equipment leg that stands in the bark. Paint, tape or a scratch, at 200mm or whatever you laid. Bark covering the mark is fine. 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.

Rake the high-traffic spots back level every few weeks through summer, and expect a proper top-up every 12 to 24 months. The bark is not failing when it thins. It 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 does not graze knees.

Next Steps

We stock all five certified products, Softwood Play Grade Chips, Hardwood Play Grade Chips, Pine Play Bark, Pine Play Nuggets and Deluxe Pine Play Area Bark, in bulk bags, jumbos and multipacks, with test reports available on request for every one. Run your numbers through the calculator above, add your settlement allowance, and get the whole job delivered in one drop. Enjoy the soft landings!

Got a play area depth question we haven't covered, or a tip from your own garden build? Drop it in the comments below — I read and reply to every one.

FAQs

How much will 100 litres of bark chippings cover?

A 100L bag of bark chippings covers 1m² at 100mm deep, half a square metre at 200mm, and a third of a square metre at 300mm. On play depths, small bags are for top-ups, not for filling the area.

How big is a 100L bag of bark?

A 100L bag of bark holds 0.1 cubic metres, a tenth of a standard bulk bag. Our play products come in 60L and 70L packs rather than 100L, which is worth checking before you compare prices per bag.

Is 10cm of play bark enough?

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

How often should play bark be topped up?

Play bark needs a proper top-up every 12 to 24 months in a garden, plus a rake back into the landing zones every few weeks through summer. Thinning is bark behaving like a natural material, not failing.

What is the difference between bark chippings and play bark?

Play bark is screened for particle 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 bark chippings?

A membrane under play bark is worth having to keep the bark and the soil apart, and it must be a permeable one so the surface still drains. Fit it before the equipment goes in, not after.