We have been using Composite Decking (WPC) since last 7-8 years and each area on an average is 300 Sq. Mtr. Around Swimming Pool in most cases but we have also done around a large artificial pond in a Garden house of a tycoon area 2200 sq. mtr. around 2 years ago.
We use Joist made of same material with choice of 3 different profiles. span of joist 280~330mm, Clips and screws made of Stainless Steel. decking profiles used are 25 to 35mm hollow or 25mm solid. Joist 30×51 hollow or 30-60 hollow or 25-40 solid.
We find WPC is much easier and complaint free so far compare to Wooden Decking we have been doing since 1984 till we introduced WPC 8 years ago. the Summer temp. in our region is 49-51 deg. C. so, you can imagine what am I talking about. 😀