I have an exterior brick wall on my home, and had a window leaking into the wall for some time until I discovered it. In remediating the mold and rot, I had to rip out the drywall, OSB, and insulation from the inside of the dwelling. After I fixed the windows, and while the brick wall was still exposed from inside the home, I tested the window repairs by setting a sprinkler spraying directly onto the exterior brick faÃ§ade, and watched for drips from inside. Well, to my dismay, although the windows no longer leaked, water was dripping everywhere and was not migrating though cracks in mortar, but directly through my intact bricks! I subsequently selected a silane-siloxane sealer and applied it to several hundred square feet of the exterior brick and mortar with just a garden sprayer. After drying, I did the test again, an NO WATER came through the bricks at all!