In a 100-square-foot wall, how much water can diffuse through drywall without a vapor diffusion retarder?

In a typical scenario, a standard drywall system without a vapor diffusion retarder allows water vapor to diffuse through it at a certain rate. For a 100-square-foot wall, the amount of water that can diffuse through the drywall is measured in cups, and it is generally accepted that approximately 1 cup of water can permeate through a wall of this size under normal conditions.

This diffusion process is key in understanding moisture management in homes and ensuring that walls don’t experience excessive moisture buildup, which can lead to mold growth and structural damage. Therefore, the answer indicating 1 cup reflects a realistic expectation of moisture movement through the drywall and aligns with common building science principles regarding vapor diffusion.