Many of you in the playground profession must scratch you head at why surfacing is 4”-10” lower than when it was installed in the play area. This goes for all surfacing material wood chips, pea gravel, sand, except rubber nuggets and hard surfacing. The three mentioned surfaces all settle and erode.
Wood chips decompose creating bacterial activity that promotes a peat material at its base giving it the cushion. As it decomposes and settles the maintenance staff needs to reapply material around the play equipment to maintain acceptable safety levels.
Pea Gravel while it will act like marble when first placed in a play area will erode significantly. This constant grinding of stones and water will pulverize the gravel creating hard cement like material under the pea gravel. The impact attenuation will perform admirably when first placed in service. Not for long the activity placed on the surface will cause erosion and settling creating a very hard surface just under the surface. The safety risk to the children is considerably increased. My suggestion is for the staff to use equipment to break up these solids or replace the surfacing with a more acceptable product. I find that pea gravel is an adult’s reaction to cost concerns as opposed to overwhelming negative characteristics of the product and higher risk factors than any of the alternative surfacing products.
Sand has different properties. Sand will mainly compact, while it will erode and settle providing less impact attenuation than when initially installed it will not get rock hard and will always provide some level of safety. Because there is erosion and settling occurring such as wind storms, rain, and people playing on the surface it will get compacted and provide less volume. To resolve these issues your staff needs to fluff the sand with a machine or by hand, and add more sand around play equipment. Children love sand. It squishes, builds, has texture and is cool in the summertime, all aspects that make it interesting to children. I have found they enjoy this material better than all the other surfacing materials. Yes it is dirty, yes cats think of it as a large litter box and older un-American deviants will break bottles and the debris will remain in the sand. However, all these issues can be attended to by good maintenance practices. If you have ever watched a child fall on their head from 5’-6’ you will agree sand is a high performing safety surface after that child walks away with only a tear in their eye.
I will address rubber surfacing products in the future.
Thank you