There are several reasons why water may be entering the house. Water is getting behind the brick wall and running along the beam to a point where it eventually drips down. It is possible that the water is entering under the soffit or it is entering the wall through poorly sealed window frames or door attachments. Once it has entered, it is either being drawn toward the inside wall by poorly positioned metal ties that hold the brick wall parallel to the inside wall, or the brick wall is touching the inside wall and the water is seeping through. If the windows and doors are tightly sealed, you should add a wood trim to the top of the soffit to stop any water from entering. The air holes found at the bottom of all brick walls may also be blocked. The air holes serve a dual purpose: Firstly, they allow excess water that enters the space between the brick wall and the inside wall to drain outside, and they also force pressure on the inside of the brick wall. If water-or air-is entering through cracks in the wall, the air pressure will push back away water trying to get inside. If none of these solutions work, there are two other possibilities. One is to open the brick wall at the end of that I beam and be sure that it is insulated and watertight. The other option is to install some aluminum siding over the brick wall. The brick wall may no longer be exposed, but if properly installed the siding will eliminate the problem immediately.