I plan on finishing my basement ceiling using the ceiling max grid/tile system. I need to lower the ceiling about 1 1/2" to clear all obstructions. In order to do this I was planning on using 2 x 4's. I planned on installing several rows perpendicular to the ceiling joists. I was then going to mount the various top hangers of the ceiling max system to the 2 x 4's. This would bring mt ceiling down 1 1/2'' below the joists clearing all obstructions. My concern is as follows: I would be screwing the 2 x 4's into the "short" dimension of the joist (The 1 1/2" edge). I would think that I run the risk of splitting the joist &/or perhaps compromising its structural integrity. In all I'd need to run aprroximately 6-7 rows of 2 x 4's, and the each joist would be getting drilled into numerous times by the different rows of 2 x 4's. Any thoughts on this? I suppose an alternative to drop my ceiling might be to install would parallel to the ceiling joists like sister joists & then install the 2 x 4's into these sister joists. Would this be better interms of preserving the joists?

On several walls in my home it looks as if someone threw water on them and let it run down the wall. The stains are underneath windows mainly and one is on the other side of the bathroom. What causes this?