What specific load must a deck ledger attachment to a house resist?

The correct answer highlights the fact that a deck ledger attachment to a house must primarily resist lateral loads. In this context, lateral loads refer to the forces acting horizontally against the beam or ledger board due to factors like wind, weight distribution, and the dynamics of movement on the deck.

When a deck is constructed, it is essential for the ledger board to have a solid attachment to the house in order to provide stability—not only vertically but especially laterally. This lateral movement tends to exert significant forces, requiring the ledger to withstand high levels of stress.

While vertical loads such as the weight of the deck, furniture, and occupants must also be accounted for, they are generally not as critical for the ledger's attachment compared to lateral forces, especially concerning safety and structural integrity in high winds or dynamic loading situations. Hence, ensuring that the ledger can handle a lateral load of 3,000 lb is crucial for the overall safety of the structure.