How should lag screws or bolts be installed on a deck ledger?

Installing lag screws or bolts in a staggered pattern is recommended for securing a deck ledger because this arrangement reduces the risk of potential weaknesses in the structural connection. When lag screws are installed in a straight line, the load bearing points can create a point of failure as they concentrate stress in one area of the ledger board. This can lead to increased risk of splitting the wood or failing to provide adequate support.

In contrast, a staggered pattern distributes the load more evenly across the ledger board and the underlying framing, enhancing the overall strength and stability of the connection. This approach helps to manage the tension and shear forces more effectively, providing a better structural integrity for the deck over time. It is essential for maintaining the safety and longevity of the deck structure.

The other options typically do not provide the same level of structural benefit, leading to potential issues with stability or load distribution. A diagonal pattern or grouping screws in threes may not adequately address the forces involved and could lead to diminished effectiveness in securing the ledger to the framing.