What is the required horizontal lapping for a water-resistant barrier?

The correct answer reflects the common construction standard for horizontal lapping of water-resistant barriers, which is typically 2 inches. This specification ensures that there is sufficient overlap between the layers of the barrier, preventing water intrusion and protecting the building's envelope. Proper lapping is critical in managing water drainage and protecting structural components from moisture damage.

By requiring a 2-inch overlap, it provides a balance that allows for effective sealing while accommodating potential expansion and contraction of building materials due to temperature fluctuations. Ensuring this overlap helps maintain the integrity of the barrier in resisting wind-driven rain and other forms of moisture penetration, which could compromise the building's structure and lead to mold growth or deterioration over time.