A flexible seal system for provision of a substantially watertight seal between adjacent concrete panels (11, 12); said system comprising a first flexible seal member locatable proximate a first end of one said concrete panel; said first flexible seal member including: at least one anchor component; a surface component suitable for overlaying a portion of an outer surface of said concrete panel; said surface component extending from said at least one anchor component which is projecting from said surface component and which is suitable to be embedded within said concrete panel; a second flexible seal member locatable proximate a second opposite end of an abutting said concrete panel; said second flexible seal member including; - at least one anchor component; - a surface component suitable for overlaying a portion of an outer surface of said abutting concrete panel; said surface component of said second flexible seal member extending from said at least one anchor component, which is projecting from said surface component and which is suitable to be embedded within said abutting concrete panel; characterized in that the surface component of said first flexible seal member extends integrally to an overlap component said overlap component suitable for extending beyond said first end of said concrete panel, 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. at least one anchor component; a surface component suitable for overlaying a portion of an outer surface of said concrete panel; said surface component extending from said at least one anchor component which is projecting from said surface component and which is suitable to be embedded within said concrete panel; a second flexible seal member locatable proximate a second opposite end of an abutting said concrete panel; said second flexible seal member including; - at least one anchor component; - a surface component suitable for overlaying a portion of an outer surface of said abutting concrete panel; said surface component of said second flexible seal member extending from said at least one anchor component, which is projecting from said surface component and which is suitable to be embedded within said abutting concrete panel; characterized in that the surface component of said first flexible seal member extends integrally to an overlap component said overlap component suitable for extending beyond said first end of said concrete panel, - at least one anchor component; - a surface component suitable for overlaying a portion of an outer surface of said abutting concrete panel; said surface component of said second flexible seal member extending from said at least one anchor component, which is projecting from said surface component and which is suitable to be embedded within said abutting concrete panel; characterized in that the surface component of said first flexible seal member extends integrally to an overlap component said overlap component suitable for extending beyond said first end of said concrete panel, 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.