Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: March 1, 2001
On the inside face of a parapet or wherever a masonry wall intersects a lower roof, I have seen cases where the masonry flashing exits the wall one or more courses above the top of the retaining bar for the roof base flashing. Will this cause any problems? There can be problems whenever the roof base flashing and the masonry through-wall flashing are not properly integrated. This is especially true if the masonry flashing stops or is held back slightly at the face of the masonry. If the flashing does not extend beyond the face of the wall, there is a chance the water may run around the end of the flashing and re-enter the wall below. Another good reason for projecting the through-wall flashing beyond the face of the wall is to prevent the outlet edge of the masonry flashing from being inadvertently covered when the roof membrane and roof base flashing are replaced. This would seal off the masonry flashing and route the water under the roofing. (DonÆt laugh; IÆve seen it happen.)
But there can be problems even when the masonry flashing does project beyond the face of the wall if it exits more than one or two courses above the roof base flashing. When water flows across the face of the wall or out from the weep holes, it will flow over the masonry between the bottom of the masonry flashing and the top of the roof base flashing.
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