The most attractive aspect of composite decking over existing decks is that it saves more time. But can you do this? Simply put, yes you can. Laying a new composite deck over an existing deck can save more time and money. This seems like a logical choice, but there are many drawbacks.
Before you start your build, you need to consider the weight of the existing wood deck, how much does it weigh? Is it new enough? Is the deck rotting and cracking? These questions are very important because when you need to install composite decks over the existing ones, the former will directly affect the latter. If your wood decking is rotting and cracking, the life of the composite deck on which it is laid will be shortened as well. Although composite material is highly resistant to rot, moisture can be trapped underneath because of the substructure. This can lead to damage to the substructure and decay of the composite decks.
If your pressure-treated decks are relatively new, then it will not affect the overall use and life of the composite deck boards. Even if it does, there will not be as much damage as with older decks. But if your wood deck is new, why would you want to convert the wood deck to composite? You need to take into account the price of composite materials because composite decking is really very expensive.
