It depends on the size of the deck project - the larger the project, the more piles will be required. Also, whether the deck is attached to an existing structure or is free-standing also makes a difference. A deck attached to an existing structure requires fewer smaller diameter piles since the existing structure stabilizes the lateral load. A free-standing deck requires more and larger diameter piles to support and control the lateral load. The number of piles and their location are provided by the deck designer and validated by our Engineering Department. The rule of thumb is a spacing of 8 to 10 feet (2.4 to 3 m) between the piles.