Our firm did the masonry work for a new school. Ever since the building was completed, there has been a leak just below the point where the school roof intersects the gymnasium wall. The roofer claims the roof is not the source of the leak. The architect thought the leak was occurring because we forgot to put weep holes in this area. However, we feel the real cause was the architect's requiring us to hold the flashing back 1/2 inch from the face of the wall. We agreed to install weep holes in the masonry to see if it would help, and did so by removing brick units and replacing them with an open head joint on one side. Before reinstalling the brick, we inspected the flashing to make sure it was not damaged. We found that in all cases the flashing was held back no farther than 1/2 inch from the face of the wall. Yet after the repairs, the leaks were worse than they were before. What should we do?
The situation you describe is fairly common. The source of the leak is related either to the roof, the wall, or the through-wall flashing. Although the roofer says he inspected the roof, some leakage may be occurring at the horizontal termination at the top edge of the roof base flashing. Because the flashing is held back from the face of the wall, some water may be running around the end of the flashing and continuing down the wall, causing the leakage. There also may be defects, such as poorly sealed lap joints or cuts in the flashing. Adding weep holes along a flashing that is improperly designed or installed actually can create a leakage problem. The weep holes allow water running down the face of the wall to enter the wall easily at the flashing level. This water can flow onto the flashing and leak through any flashing defects or simply travel down to the wall below because the flashing was held short. The best way to resolve the problem would be to conduct a water test of the roof, the top termination of the roof, the masonry wall, and even the roof and coping at the top of the gymnasium. If the flashing is the cause of the problem, it may need to be replaced. The new flashing should extend through the wall and cover the top edge of the roof flashing.