A flexible seal system for provision of a substantially watertight seal between adjacent concrete panels; said system comprising a first flexible seal member proximate a first end of one said concrete panel; said first flexible seal member including a surface component extending over a portion of an outer surface of said concrete panel; said surface component extending from at least one anchor component projecting from said surface component and embedded within said concrete panel; said first flexible seal member further including an overlap component extending from said surface component beyond said first end of said concrete panel; and a second flexible seal member proximate a second opposite end of an abutting said concrete panel; said second flexible seal member including a surface component extending over a portion of a surface of said abutting concrete panel; said surface component of said second flexible seal member extending from at least one anchor component projecting from said surface component and embedded within said abutting concrete panel; and wherein the overlap component of the first flexible seal member is structured and selected in use to overlap the surface component of the second flexible seal member sufficient to permit welding of at least a portion of said overlap component of said first flexible seal member to at least a portion of said surface component of said second flexible seal member so as to form a continuous welded seal between and along the length of said first flexible seal member and said second flexible seal member.