Abstract: Gaps between adjacent members in a building construction are sealed by applying a self-adhering barrier sheet to the adjacent members to span the gap. The self-adhering barrier sheet includes a flexible sheet of a barrier material. The flexible sheet has opposing edges, of which at least one is tapered. A pressure sensitive adhesive is applied to at least a portion of at least one major surface of the flexible sheet. The edges of the self-adhering barrier sheet are adhered to the adjacent structural elements by means of the pressure sensitive adhesive. The pressure sensitive adhesive has a thickness equal to or less than the maximum thickness of the flexible sheet. Where two self adhering barrier sheets overlap at an angle on a substrate, the tapered edge of the underlying sheet allows a smooth transition for the overlapping sheet, preventing the formation of an open gap between the barrier sheets and the substrate where air and moisture can penetrate.