About half of my attic has plywood sheeting installed on the attic floor. In the cavities there are R-19 batts. This allows for good storage areas, but not so good insulation. I have been slowly adding R-30 unfaced batts on top of the plywood sheeting. I have come to an area where the master bath is located just below the attic floor. Here I noticed there is about a 1" gap in the sheeting along the exterior wall side of the attic just above the shower and tub of the bath below. My first thought was whomever installed this sheeting did a lousy job here leaving this gap . The rest of the attic floor sheeting is laid carefully with no spaces or gaps anywhere ~except~ right here above the master bath. There are other mistakes in the insulation of the home so I figured this was just one more goof up. At first I thought it was a mistake, I now think maybe it was on purpose to allow for escaping moisture. I am on the fence as to whether I should cover this gap with 9 inches of unfaced fiberglass or stop just short of the gap with my insulation project. What's your opinion?