Wet Pour Rubber Outdoor Surfaces- How To Lay

Wet pour rubber is a soft colourful surface found commonly in playgrounds for children’s play. The benefits of a wet pour system are.

  • Shock absorbency
  • Slip resistance
  • Uniform and seamless
  • Protection for critical fall height
  • Minimise injury risk
  • Creative design freedom
  • Expert installation guidance
  • All the colours of the rainbow

It is  a two layer system of rubber crumb which is bonded together with a resin. The rubber and resin is mixed insitu and so is poured when ‘wet’ into place so getting it’s name wet pour rubber. The amount of rubber to resin has to be carefully controlled and the type of resin used selected for the prevailing conditions.  A base layer is laid first , this binds to the aggregate/ tarmac below and provides a cushion. Base wet pour rubber has larger granules than topping material and may be a recycled rubber. The second wearing course is a finer virgin rubber which is available in a wide range of colours. This is floated  level to the required thickness.

What can go wrong?

Wet pour is always better installed by a experienced installer. The cost of the materials is large part of the cost of any surface  although it looks relatively simple to lay it can encounter a number of problems. Below are just a few of the problems which can be commonly experienced by schools using less experienced  companies.

Weather too warm – if the weather is too warn the resin can become very runny. This can be a problem on roof playground and courtyards in particular. Before the resin can set it can run from the top rubber crumb and settle into the bottom crumb layer. This makes the top crumb layer crumble . Although some loose rubber is normal onto of the surface and doesn’t detract from the longevity of the surface or the CFH the rubber crumb should continually have a layer of loose crumb on the top.

Weather to wet or humid- some moisture is required for the resin to cure fully. If the underlying surface contain too much moisture or it rains after the surface has been laid, this causes an accelerated reaction in the resin which forms bubbles on top of the surface.

Weather too cold-the resin binder requires a minimum temperature to cure. In colder weather the resin will take longer to cure, and may not cure fully.

Old Rubber- Rubber which has been stored for a long period of time may have been contaminated with condensation. Often when a bag is left the difference between night and day temperatures can cause sweating in the bag, this additional moisture is able to permeate the rubber . Visually the rubber wont look any different , however when laid area’s of bubbly will become evident over the curing time.

Cheap Rubber – although a wet pour surface seems relatively expensive , correctly installed it lasts for many years and provides a good value over it lifetime.

Non-Virgin rubber- made from vehicle tyres is only suitable as a base material after careful processing. Recycled sbr rubber can be dyed different colours and used by some companies as a cheaper alternative. Once laid the difference isn’t noticeable until the surface is played on. As the sun heats the surface the contaminants which have been absorbed from roads such as oil leach out of the rubber. This leads to staining on clothes, shoes and hands. Many of these contaminants are not safe for children to be in contact with. All surface materials should be from a reputable supplier and the top layer should only be virgin rubber.

Laid well with the correct material a wet pour rubber surface can provide a soft safe outdoor surface for many years. It doesn’t lend itself to being a easy DIY product. Although small patches of damage can be repaired with a DIY repair kit, this contains carefully measured amount of products and care must be taken in installation of even small areas.