Brick Veneers and Leaky Windows

If not properly flashed, all masonry wall openings possess a potential moisture problem. In brick veneer systems there are two distinct methods for properly installing the flashing membrane, as shown in Figures 1 & 2. In Figure 1 the flashing membrane* is turned up at the ends and placed inside the head joint, forming a dam. This acts as a directional aid, guiding water through the weep holes to the exterior surface of the wall.

 In Figure 2 a self adhesive preformed end dam is placed under the flashing membrane. (shown on top of flashing in the drawing for clarity).

Figures 3 & 4 show the complex detail required to properly flash a brick veneer bay window. Preformed end dams are used in a stair-step fashion, culminating with a flashing tray and weep hole to direct collected water out of harms way.

Figure3:

The installation of the flashing for a sill condition is shown in Figure 6. An end dam is used to act as a moisture deterrent.The flashing collects any entrant water, and the end dam ensures that the water will be directed to the exterior. Weep holes are installed to provide an avenue of egress for the moisture. Ideally the end dam would be placed 6" to 8" beyond jamb lines above all wall openings.

Figure 6

The diagnosis of a leaky window usually requires removing some brick to see what is happening inside the wall. I suggest hiring a Masonry Consultant to Determine the cause of your problem:

Items to be checked:

• There should be flashing and weep holes directly above the window line
• Sill should not be constructed from several brick units in cold and/or wet climates - there are just too many mortar joints that can let water in.
• Flashing should be installed directly below the sill and turned up to form end dams