Hi To share my experience. My contractor had just finished installing High-density polyethylene (HDPE) PLASTIC LUMBER on my planter. After checking on some quotation, their price is most reasonable in term of quality and substainbility as comparing to the pro/cons of WPC and woods. Infact, it was the same contractor introduced by one forumer bunnymummy. You can find more info in their website http://www.wagonequipment.com.sg See photos of my planters in below link. My planter