When flashing is used below parapet coping, steps must be taken to maintain the masonry bond with the wall below. It is a mistake to employ metal flashing fully between the coping and the wall. This type of moisture barrier creates a ponding effect which may allow the stone to deteriorate when the parapet is subject to freezing and thawing. Through-wall type flashing should be used as shown on the detail below. This allows the coping to wick and drain to the weep holes below while maintaining the masonry bond with the walls.
Where non-masonry backup wall systems are used, metal lathe should be attached to the backup to span the wall continuously so that mortar may be used to bond the coping to the wall.
Flashing groves can be cast into the tops of stones. Where dovetail reglets are required, galvanized metal units can be cast into a formed side of the stone, kept sufficiently away from the edge.
Cramp anchors or end dowels may be used for anchoring coping together and are less costly to install than bottom dowels which must be tediously located and sealed or capped when used in conjunction with flashing.
Copyright © 1997-2003 by Cast Stone Institute, Inc. Reproduced with permission by Cast Stone Institute, Inc.