What is play grade timber?
To start with, you need to select the right species of timber for your playground.
There are lots of species that are suitable, from many countries around the world.
The following list contains some examples, but is not exhaustive: Radiata Pine, Yellow Pine, Cedar, Oak, Spruce, Robinia and many others.
Some of these timber species, especially the softwood types, will require some kind of timber preservative treatment to enhance their resistance to rot or mould, and also to repel insect attacks. One of the most common methods used for play-grade timber preservation is Pressure Treatment. This process involves impregnating the timber with a preservative chemical, which will act as a fungicide, and extend the useful life of the timber. This process uses high pressure to force the preservative chemical deep into the timber before being allowed to dry out again. Preservatives should be to BS EN 351-1 and EN 351-2, and the Treatment process should be to BS 8417. No coal-tar oils (i.e. creosote) should be used for play-grade timber, nor CCA (Copper Chrome Arsenic) as these types of treatment can be poisonous – not what you want in a playground! A more suitable type of preservative is Micronised Copper Azole (MCA) as this is both an effective treatment type and also not harmful in playground environments.
Some hardwood timbers are naturally resistant to rot, and can last for many years without preservative treatment.
In any case, whichever species you select, play-grade timber will not crack excessively. Being a natural material, timber will swell and shrink and can even change shape when subjected to the elements. This can cause cracks to appear along some timber structures, and if these cracks get large enough, they can become a finger-trap hazard. Play-grade timber has been through specially-controlled drying processes which helps to prevent any cracks from becoming too large.
Finally, any timber used for playground environments should be sanded or planed completely smooth, so that no risk of rough edges or splintering can occur.
If you use any metal fastenings in your play structure, check to ensure that they will not be corroded by the timber species used or by any paint or preservative.
To summarise, play-grade timber is:
- The right species
- Treated with a safe Preservative Chemical where required
- Resistant to large cracks and gaps
- Planed or sanded smooth to avoid splintering