What is a problem with many wall claddings installed against the WRB?

The identified problem with many wall claddings installed against the Weather Resistant Barrier (WRB) is that they leave no air space to drain water and no air space to help reduce vapor diffusion. This is significant because effective moisture management is crucial in building construction to prevent water accumulation that can lead to mold growth and structural damage.

When cladding is installed directly against the WRB without an air gap, any moisture that penetrates the cladding does not have a drainage path. This can lead to moisture being trapped against the WRB, which may compromise the barrier's effectiveness and create conditions that foster mold and decay. Additionally, without an air space, vapor diffusion cannot be adequately managed. Moisture that vaporizes can become trapped, potentially leading to condensation issues within the wall assembly.

Creating an air gap allows for the movement of air, which aids in both drying out any moisture that may have entered and minimizing the potential for vapor-driven moisture issues. Therefore, ensuring adequate air space when installing wall cladding is essential for the longevity of the building envelope and overall durability.