Effects of pressure equalization on the performance of residential wall systems under extreme wind loads

During strong windstorms, sheathing and siding on residential, wood-framed, wall systems have commonly failed. In the current study, a clear difference is observed in the rate of failure occurrence for wall sheathing above or below the eaves. This observation can be explained from tests examining ultimate capacities and pressure equalization of both single- and multilayer residential, wood-framed, wall systems using realistic fluctuating loads. The results indicate that pressure equalization is a critical parameter in the performance of both the cladding and exterior sheathing. With interior sheathing included, significant pressure equalization was observed to occur across the exterior sheathing, because pressure equalization is observed to increase with load (and damage) levels. This substantially increases the ultimate capacity of these wall systems; however, the construction details of the various exterior layers play an important role in the levels of pressure equalization across each layer.