Twice lately, during fairly hard storms with driving rain, I’ve found water dripping into the basement from the subflooring above. There is a distinct hole, where I guess it has rotted through, that is right along the rim joist, (which coincidentally, but totally unrelated I think) I’ve just been insulating. On the floor above, right above the leak spot, the hardwood flooring right along the wall is discolored. This area is pretty much in line with the side of a window in the brick face of the house. And this spot is about a foot or so above the outside grade. So it seems that from somewhere, a decent amount of water is getting behind the brick, and then into the wall, under the wood flooring, and then leaking down into the basement. I know windows are a common source of such water incursions, and just this past fall, I went around caulking any gaps I could find around all the windows on the front of the house. The roof was just replaced a year ago, so I don’t think anything up there is a problem, especially since it has only done this during heavy rain with wind – if it was a roof issue, I would expect leaks every time it just rained a good amount. I know the brick/mortar itself is porous, but there are weep holes in the brick that are open – I can see the housewrap membrane through the holes. So I’m stumped as to how the water is actually getting into the house. Shouldn’t the membrane protect from that?

I’ve read that even if the membrane has some punctures, it is pretty unlikely for water to come in, because apparently, the moisture pretty much clings to the back of the bricks and doesn’t cross the 1-inch air gap to the sheathing. I’ve also thought about the bricks wicking water UP from the ground/mulch in front of the house, but again, even so, wouldn’t the membrane protect from it actually getting into the house?