Mike and my fellow beekeepers: When I seal the joints in an inner cover for ant control, I seal the joint between the plywood (or Masonite) and the inner cover's outer rim. That's where the ants live. I most definitely do not block the ventilation out of the top of the hive. In fact the rims of all my inner covers have about a 1" notch to provide increased ventilation and an upper entrance. W. G. Miller Gaithersburg, MD