It is important to recognize, though, that the moisture exchange performance of the two products has not been a factor in such evaluations by the code authorities or by local building departments. These entities must assume that the sheathing will be installed under roofing, cladding, and weather barrier systems designed and installed to minimize moisture infiltration of the underlying structural panels; however, out in the workplace, construction professionals see numerous instances of design and/or construction failures resulting in extended periods of moisture entry and ensuing severe deterioration of the underlying plywood and OSB sheathing.