hi im new here an im just starting to build my own viv from a old wardrobe the wood is already melamind but do i need to add extra coating of some type of waterproofing as i want to put expanding foam on top of the wood as a background any ideas or help would be ace as i really want to make this right and last as long as possible as my other viv is fallin apart as i only used gloss as a water proofing lol thanks